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TPS40210DRCTG4

TPS40210DRCTG4

  • 厂商:

    BURR-BROWN(德州仪器)

  • 封装:

    VFDFN10_EP

  • 描述:

    Boost, Flyback, SEPIC Regulator Positive Output Step-Up, Step-Up/Step-Down DC-DC Controller IC 10-V...

  • 数据手册
  • 价格&库存
TPS40210DRCTG4 数据手册
Order Now Product Folder Technical Documents Support & Community Tools & Software TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 TPS4021x 4.5-V to 52-V Input Current Mode Boost Controller 1 Features 3 Description • The TPS40210 and TPS40211 are wide-input voltage (4.5 V to 52 V), nonsynchronous boost controllers. They are suitable for topologies which require a grounded source N-channel FET including boost, flyback, SEPIC, and various LED Driver applications. The device features include programmable soft start, overcurrent protection with automatic retry, and programmable oscillator frequency. Current mode control provides improved transient response and simplified loop compensation. The main difference between the two parts is the reference voltage to which the error amplifier regulates the FB pin. 1 • • • • • • • • • • • • Functional Safety-Capable – Documentation available to aid functional safety system design For boost, flyback, SEPIC, LED drive apps Wide input operating voltage: 4.5 V to 52 V Adjustable oscillator frequency Fixed frequency current mode control Internal slope compensation Integrated low-side driver Programmable closed-loop soft start Overcurrent protection External synchronization capable Reference 700 mV (TPS40210), 260 mV (TPS40211) Low current disable function Create a custom design using the TPS4021x with the WEBENCH Power Designer Device Information(1) PART NUMBER PACKAGE BODY SIZE (NOM) TPS40210 HVSSOP (10) 3.05 mm x 4.98 mm TPS40211 VSON (10) 3.10 mm x 3.10 mm (1) For all available packages, see the orderable addendum at the end of the datasheet. 2 Applications • • • LED lighting Industrial control systems Battery-powered systems Simplified Schematic VIN TPS40210 1 RC 2 SS 3 VOUT VDD 10 BP 9 DIS/EN GDRV 8 4 COMP ISNS 7 5 FB GND 6 RSENSE UDG-07110 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 4 5 6.1 6.2 6.3 6.4 6.5 6.6 5 5 5 5 5 8 Absolute Maximum Ratings ...................................... ESD Ratings ............................................................ Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics........................................... Typical Characteristics .............................................. Detailed Description ............................................ 12 7.1 7.2 7.3 7.4 Overview ................................................................. Functional Block Diagram ....................................... Feature Description................................................. Device Functional Modes........................................ 12 12 13 25 8 Application and Implementation ........................ 26 8.1 Application Information............................................ 26 8.2 Typical Applications ................................................ 26 9 Power Supply Recommendations...................... 37 10 Layout................................................................... 37 10.1 Layout Guidelines ................................................. 37 10.2 Layout Example .................................................... 37 11 Device and Documentation Support ................. 40 11.1 11.2 11.3 11.4 11.5 11.6 11.7 Device Support...................................................... Documentation Support ....................................... Related Links ........................................................ Receiving Notification of Documentation Updates Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 40 40 40 41 41 41 41 12 Mechanical, Packaging, and Orderable Information ........................................................... 41 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision F (March 2015) to Revision G • Page Added functional safety bullet to the Features ...................................................................................................................... 1 Changes from Revision E (October 2011) to Revision F Page • Added Updated Land Pattern ................................................................................................................................................. 1 • Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section ................................................................................................. 1 Changes from Revision D (April 2010) to Revision E Page • Changed the Revision date from D, April 2010 to E, October 2011 ...................................................................................... 1 • Added Q1 and Q3 to Figure 36 by illustrator........................................................................................................................ 35 Changes from Revision C (October 2008) to Revision D Page • Changed CISNS to CIFLT ......................................................................................................................................................... 21 • Changed CISNS to CIFLT ......................................................................................................................................................... 21 • Changed equations 22 and 23 ............................................................................................................................................. 22 • Changed corrected equation 25 ........................................................................................................................................... 23 • Added "R1 is the high side feedback resistor in Ω" and " fL is the desired loop crossover frequency, in Hz" ..................... 23 • Changed paragraph with new input...................................................................................................................................... 23 • Changed capacitor value from µF to F ................................................................................................................................. 23 • Changed 0.2 with 0.1 in MIN col in Design Example Specifications table ........................................................................... 27 • Deleted text from Peak efficiency row .................................................................................................................................. 27 • Changed 10 V with 8 V in TOP conditions column ................................................................................................................ 27 • Changed 42.8% to 42.9% in eq 32....................................................................................................................................... 28 2 Submit Documentation Feedback Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 • Added (VFD) and changed approximate duty cycle from 42.8% to 42.9% ........................................................................... 28 • Changed equations 32, 34, 35, 36, 37, 38 and 39 ............................................................................................................... 28 • Changed equations 47, 48, 49, 50, 51 and 53 ..................................................................................................................... 30 • Changed equations 58, 60, 61, 62 ....................................................................................................................................... 31 Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 3 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com 5 Pin Configuration and Functions DGQ 10-Pin Top View DRC 10-Pin Top View RC 1 10 VDD SS 2 9 BP 1 10 RC 1 SS 2 9 VDD BP DIS/EN 3 8 GDRV DIS/EN 3 8 GDRV COMP 4 7 ISNS COMP 4 7 ISNS FB 5 6 GND FB 5 6 GND Pin Functions PIN NAME NO. I/O DESCRIPTION BP 9 O Regulator output pin. Connect a 1.0-μF bypass capacitor from this pin to GND. COMP 4 O Error amplifier output. Connect control loop compensation network between COMP pin and FB pin. DIS/EN 3 I Disable pin. Pulling this pin high places the part into a shutdown mode. Shutdown mode is characterized by a very low quiescent current. While in shutdown mode, the functionality of all blocks is disabled and the BP regulator is shut down. This pin has an internal 1 MΩ pulldown resistor to GND. Leaving this pin unconnected enables the device. FB 5 I Error amplifier inverting input. Connect a voltage divider from the output to this pin to set output voltage. Compensation network is connected between this pin and COMP. GDRV 8 O Connect the gate of the power N channel MOSFET to this pin. GND 6 - Device ground. ISNS 7 I Current sense pin. Connect an external current sensing resistor between this pin and GND. The voltage on this pin is used to provide current feedback in the control loop and detect an overcurrent condition. An overcurrent condition is declared when ISNS pin voltage exceeds the overcurrent threshold voltage, 150 mV typical. RC 1 I Switching frequency setting pin. Connect a resistor from RC pin to VDD of the IC power supply and a capacitor from RC to GND. SS 2 I Soft-start time programming pin. Connect capacitor from SS pin to GND to program converter soft-start time. This pin also functions as a timeout timer when the power supply is in an overcurrent condition. VDD 10 I System input voltage. Connect a local bypass capacitor from this pin to GND. Depending on the amount of required slope compensation, this pin can be connected to the converter output. See Application Information section for additional details. 4 Submit Documentation Feedback Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 6 Specifications 6.1 Absolute Maximum Ratings over operating free-air temperature range unless otherwise noted (1) Input voltage Output voltage MIN MAX VDD –0.3 52 RC, SS, FB, DIS/EN –0.3 10 ISNS –0.3 8 COMP, BP, GDRV –0.3 9 UNIT V TJ Operating junction temperature –40 150 °C Tstg Storage temperature –55 150 °C (1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 6.2 ESD Ratings VALUE V(ESD) (1) (2) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) ±1500 Charged-device model (CDM), per JEDEC specification JESD22C101 (2) ±1500 UNIT V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 6.3 Recommended Operating Conditions MIN MAX VDD Input voltage 4.5 52 UNIT V TJ Operating Junction temperature -40 125 °C 6.4 Thermal Information TPS40210 THERMAL METRIC (1) TPS40211 HVSSOP VSON 10 PINS 10 PINS RθJA Junction-to-ambient thermal resistance 67.2 47.2 RθJC(top) Junction-to-case (top) thermal resistance 50.5 74.6 RθJB Junction-to-board thermal resistance 41.0 22.2 ψJT Junction-to-top characterization parameter 2.4 2.9 ψJB Junction-to-board characterization parameter 40.7 22.4 RθJC(bot) Junction-to-case (bottom) thermal resistance 15.6 8.8 (1) UNIT °C/W For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953. 6.5 Electrical Characteristics TJ = –40°C to 125°C, VDD= 12Vdc, all parameters at zero power dissipation (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX TPS40210 COMP = FB, 4.5 ≤ VDD ≤ 52 V, TJ = 25°C 693 700 707 TPS40211 COMP=FB, 4.5 ≤ VDD ≤ 52 V, TJ = 25°C 254 260 266 COMP = FB, 4.5 ≤ VDD ≤ 52 V, -40°C ≤ TJ ≤ TPS40210 125°C 686 700 714 COMP = FB, 4.5 ≤ VDD ≤ 52 V, -40°C ≤ TJ ≤ 125°C 250 260 270 UNIT VOLTAGE REFERENCE Feedback voltage range VFB TPS40211 mV INPUT SUPPLY Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 5 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com Electrical Characteristics (continued) TJ = –40°C to 125°C, VDD= 12Vdc, all parameters at zero power dissipation (unless otherwise noted) PARAMETER VDD TEST CONDITIONS MIN TYP MAX 52 V 4.5 ≤ VDD ≤ 52 V, no switching, VDIS < 0.8 1.5 2.5 mA 2.5 ≤ VDIS ≤ 7 V 10 20 μA 530 μA Input voltage range IDD Operating current 4.5 VDD < VUVLO(on), VDIS < 0.8 UNIT UNDERVOLTAGE LOCKOUT VUVLO(on) Turn on threshold voltage 4.00 4.25 4.50 V VUVLO(hyst) UVLO hysteresis 140 195 240 mV OSCILLATOR fOSC VSLP (1) 6 Oscillator frequency range (1) 35 Oscillator frequency RRC = 182 kΩ, CRC = 330 pF Frequency line regulation 4.5 ≤ VDD ≤ 52 V 260 1000 300 340 620 720 -20% Slope compensation ramp 520 kHz 7% mV Ensured by design. Not production tested. Submit Documentation Feedback Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 Electrical Characteristics (continued) TJ = –40°C to 125°C, VDD= 12Vdc, all parameters at zero power dissipation (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX 275 400 90 200 200 UNIT PWM VDD = 12 V (1) tON(min) Minimum pulse width tOFF(min) Minimum off time 170 VVLY Valley voltage 1.2 V 700 mV VDD = 30 V ns SOFT-START VSS(ofst) Offset voltage from SS pin to error amplifier input RSS(chg) Soft-start charge resistance 320 430 600 RSS(dchg) Soft-start discharge resistance 840 1200 1600 kΩ ERROR AMPLIFIER GBWP Unity gain bandwidth product (1) 1.5 3.0 MHz AOL Open loop gain (1) 60 80 dB IIB(FB) Input bias current (current out of FB pin) ICOMP(src) Output source current VFB = 0.6 V, VCOMP = 1 V 100 250 μA ICOMP(snk) Output sink current VFB = 1.2 V, VCOMP = 1 V 1.2 2.5 mA 4.5 ≤ VDD < 52 V, -40°C ≤ TJ ≤ 125°C 120 150 100 300 nA OVERCURRENT PROTECTION VISNS(oc) Overcurrent detection threshold (at ISNS pin) DOC Overcurrent duty cycle (1) VSS(rst) Overcurrent reset threshold voltage (at SS pin) TBLNK Leading edge blanking (1) 180 mV 2% 100 150 350 75 mV ns CURRENT SENSE AMPLIFIER ACS Current sense amplifier gain IB(ISNS) Input bias current 4..2 5.6 7.2 V/V 1 3 μA DRIVER IGDRV(src) Gate driver source current VGDRV = 4 V, TJ = 25°C 375 400 IGDRV(snk) Gate driver sink current VGDRV = 4 V, TJ = 25°C 330 400 7 8 mA LINEAR REGULATOR VBP Bypass voltage output 0 mA < IBP < 15 mA 9 V 1.3 V DISABLE/ENABLE VDIS(en) Turn-on voltage 0.7 VDIS(hys) Hysteresis voltage 25 130 220 mV RDIS DIS pin pulldown resistance 0.7 1.1 1.5 MΩ Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 7 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com 6.6 Typical Characteristics 68 pF CT(pF) 33pF 470 220 100 68 33 fSW - Frequency - kHz 1000 800 100pF 600 220 pF 400 1200 1000 fSW - Frequency - kHz 1200 800 600 400 200 200 470 pF 0 100 0 0 200 300 400 500 600 700 800 RT - Timing Resistance - kW 0.2 900 1000 Figure 1. Frequency vs Timing Resistance 0.4 0.6 0.8 D - Duty Cycle 1.0 1.2 Figure 2. Switching Frequency vs Duty Cycle 1.4 6 52 V 4.5 V 5 1.0 12 V 0.8 0.6 0.4 VVDD 12 V 4.5 V 52 V 0.2 IVDD – Shutdown Current – mA IVDD – Quiescent Current – mA 1.2 Figure 4. Shutdown Current vs Junction Temperature 0.5 0.4 0.2 0.0 -0.2 -0.4 4.5 V 12 V VVDD 12 V 4.5 V 52 V -0.8 -40 -25 -10 5 20 35 50 65 80 95 110 125 TJ – Junction Temperature – ° C Figure 5. Reference Voltage Change vs Junction Temperature Submit Documentation Feedback VFB – Reference Voltage Change – % VFB – Reference Voltage Change – % 52 V 8 2 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 TJ – Junction Temperature – ° C 0.4 -0.6 3 1 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 TJ – Junction Temperature – ° C Figure 3. Quiescent Current vs Junction Temperature 4 0.3 0.2 0.1 0.0 -0.1 -0.2 -0.3 -0.4 -0.5 0 10 20 30 40 VVDD – Input Voltage – V 50 60 Figure 6. Reference Voltage Change vs Input Voltage Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 Typical Characteristics (continued) 155 4.30 VUVLO – Undervoltage Lockout Threshold – V UVLO 4.20 VISNS(OC) – Overcurrent Threshold – mV 4.25 UVLO On 4.15 4.10 4.05 Figure 7. Undervoltage Lockout Threshold vs Junction Temperature 153 4.5 V 7.5 V 12 V & 20 V 30 V 7.5 V 152 30 V 151 150 12 V & 20 V 149 148 147 -40 -25 -10 5 20 35 50 65 80 95 110 125 TJ – Junction Temperature – ° C Figure 8. Overcurrent Threshold vs Junction Temperature 5 155 154 fOSC – Switching Frequency Change – % VISNS(OC) – Overcurrent Threshold – mV 154 UVLO Off 4.00 -40 -25 -10 5 20 35 50 65 80 95 110 125 TJ – Junction Temperature – ° C 153 152 151 150 149 148 147 146 145 5 10 15 20 25 30 35 VVDD – Input Voltage – V 40 Figure 9. Overcurrent Threshold vs Input Voltage 4.5 V 4.5 V 1 12 V 0 -1 30 V -2 VVDD (V) 4.5 V 12 V 30 V -3 -4 Figure 10. Switching Frequency Change vs Junction Temperature RSS(DSCH) Discharge 1200 25 1000 23 24 V 12 V 21 19 VVDD (V) 36 V 17 2 1400 29 27 4 3 -5 -40 -25 -10 5 20 35 50 65 80 95 110 125 TJ – Junction Temperature – ° C 45 RSS – Soft Start Charge/Discharge Resistance - kW 0 Slope Compensation Ratio (VVDD/VSLP) 4.5 V VVDD Off On 12 V 24 V 36 V 4.5 V 15 -40 -25 -10 5 20 35 50 65 80 95 110 125 TJ – Junction Temperature – ° C Figure 11. Oscillator Amplitude vs Junction Temperature 800 600 400 200 RSS(CHG) Charge 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 TJ – Junction Temperature – ° C Figure 12. Soft Start Charge/Discharge Resistance vs Junction Temperature Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 9 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com Typical Characteristics (continued) 180 ICOMP(SRC) – Compensation Source Current – mA 300 IIB(FB) – Feedback Bias Current – nA 160 140 120 100 80 60 40 20 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 TJ – Junction Temperature – ° C Figure 13. FB Bias Current vs Junction Temperature 200 150 100 50 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 TJ – Junction Temperature – ° C Figure 14. Compensation Source Current vs Junction Temperature 5 300 4 250 VVLY – Valley Voltage Change – % ICOMP(SNK) – Compensation Sink Current – mA 250 200 150 100 50 3 2 1 0 -1 -2 -3 -4 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 TJ – Junction Temperature – ° C Figure 15. Compensation Sink Current vs Junction Temperature -5 -40 -25 -10 5 20 35 50 65 80 95 110 125 TJ – Junction Temperature – ° C Figure 16. Valley Voltage Change vs Junction Temperature 1.10 8.8 VDIS(EN) – DIS/EN Turn-On Threshold – mV 1.09 VBP – Regulator Voltage – V 8.6 1.08 ILOAD = 0 mA 8.4 1.07 1.06 8.2 1.05 8.0 7.8 1.06 1.03 ILOAD = 5 mA 1.02 7.6 1.01 7.4 -40 -25 -10 5 20 35 50 65 80 95 110 125 TJ – Junction Temperature – ° C Figure 17. Regulator Voltage vs Junction Temperature 10 Submit Documentation Feedback 1.00 -40 -25 -10 5 20 35 50 65 80 95 110 125 TJ – Junction Temperature – ° C Figure 18. DIS/EN Turnon Threshold vs Junction Temperature Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 Typical Characteristics (continued) ACS – Current Sense Amplifier Gain – V/V 7 6 5 4 3 2 1 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 TJ – Junction Temperature – ° C Figure 19. Current Sense Amplifier Gain vs Junction Temperature Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 11 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com 7 Detailed Description 7.1 Overview The TPS4021x is a peak current-mode control low-side controller with a built in 400-mA gate driver designed to drive n- channel MOSFETs at a fixed frequency. The frequency is adjustable from 35 kHz to 1000 kHz. Small size combined with complete functionality makes the part both versatile and easy to use. The controller uses a low-value current-sensing resistor in series with the power MOSFET's source connection to detect switching current. When the voltage drop across this resistor exceeds 150 mV, the part enters an hiccup fault mode with a time period set by the external soft-start capacitor. The TPS40210 uses voltage feedback to an error amplifier that is biased by a precision 700-mV reference. The TPS40211 has a lower 260-mV reference for higher efficiency in LED drive applications. Internal slope compensation eliminates the characteristic sub-harmonic instability of peak current mode control with duty cycles of 50% or greater. The TPS4021x also incorporates a soft-start feature where the output follows a slowly rising soft-start voltage, preventing output-voltage overshoot. The DIS/EN disables the TPS40210 putting it in a low quiescent current shutdown mode. 7.2 Functional Block Diagram DIS/EN 3 COMP 4 FB 5 10 VDD + + SS 2 OC Fault Soft Start and Overcurrent E/A SS Ref 700 mV PWM Logic + Oscillator and Slope Compensation 1 9 BP 8 GDRV 6 GND 7 ISNS Driver Enable E/A RC LDO Gain = 6 OC Fault 150 mV UVLO + LEB UDG-07107 12 Submit Documentation Feedback Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 7.3 Feature Description 7.3.1 Soft Start The soft-start feature of the TPS40210 and TPS40211 is a closed-loop soft start, meaning that the output voltage follows a linear ramp that is proportional to the ramp generated at the SS pin. This ramp is generated by an internal resistor connected from the BP pin to the SS pin and an external capacitor connected from the SS pin to GND. The SS pin voltage (VSS) is level shifted down by approximately VSS(ofst) (approximately 700 mV) and sent to one of the “+” (the “+” input with the lowest voltage dominates) inputs of the error amplifier. When this level shifted voltage (VSSE) starts to rise at time t1 (see Figure 20), the output voltage the controller expects, rises as well. Since VSSE starts at near 0 V, the controller attempts to regulate the output voltage from a starting point of zero volts. It cannot do this due to the converter architecture. The output voltage starts from the input voltage less the drop across the diode (VIN - VD) and rises from there. The point at which the output voltage starts to rise (t2) is the point where the VSSE ramp passes the point where it is commanding more output voltage than (VIN VD). This voltage level is labeled VSSE(1). The time required for the output voltage to ramp from a theoretical zero to the final regulated value (from t1 to t3) is determined by the time it takes for the capacitor connected to the SS pin (CSS) to rise through a 700-mV range, beginning at VSS(ofst) above GND. TPS40210/11 VSS RSS(chg) 700 mV REF SS VSS(ofst)+700 mV RSS(dchg) VSSE(1) t0 + + 2 VSSE VSS(ofst) Error Amplifier t1 VIN - VD VOUT t2 t3 DIS UVLO OC Fault FB 5 COMP 4 UDG-07121 Figure 20. SS Pin Voltage and Output Voltage Figure 21. SS Pin Functional Circuit Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 13 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com Feature Description (continued) The required capacitance for a given soft-start time t3 – t1 in Figure 20 is calculated in Equation 1. CSS = tSS æ VBP - VSS(ofst) RSS ´ ln ç çV - V SS(ofst) + VFB è BP ( ö ÷ ÷ ø ) where • • • • • • tSS is the soft-start time, in seconds RSS(chg) is the SS charging resistance in Ω, typically 500 kΩ CSS is the value of the capacitor on the SS pin, in F VBP is the value of the voltage on the BP pin, in V VSS(ofst) is the approximate level shift from the SS pin to the error amplifier (~700 mV) VFB is the error amplifier reference voltage, 700 mV typical (1) Note that tSS is the time it takes for the output voltage to rise from 0 V to the final output voltage. Also note the tolerance on RSS(chg) given in the Electrical Characteristics. This contributes to some variability in the output voltage rise time and margin must be applied to account for it in design. Also take note of VBP. Its value varies depending on input conditions. For example, a converter operating from a slowly rising input initializes VBP at a fairly low value and increases during the entire startup sequence. If the controller has a voltage above 8 V at the input and the DIS pin is used to stop and then restart the converter, VBP is approximately 8 V for the entire start-up sequence. The higher the voltage on BP, the shorter the start-up time is and conversely, the lower the voltage on BP, the longer the start-up time is. The soft-start time (tSS) must be chosen long enough so that the converter can start up without going into an overcurrent state. Since the over current state is triggered by sensing the peak voltage on the ISNS pin, that voltage must be kept below the overcurrent threshold voltage VISNS(oc). The voltage on the ISNS pin is a function of the load current of the converter, the rate of rise of the output voltage and the output capacitance, and the current sensing resistor. The total output current that must be supported by the converter is the sum of the charging current required by the output capacitor and any external load that must be supplied during start-up. This current must be less than the IOUT(oc) value used in Equation 15 or Equation 16 (depending on the operating mode of the converter) to determine the current sense resistor value. In these equations, the actual input voltage at the time that the controller reaches the final output voltage is the important input voltage to use in the calculations. If the input voltage is slowly rising and is at less than the nominal input voltage when the start-up time ends, the output current limit is less than IOUT(oc) at the nominal input voltage. The output capacitor charging current must be reduced (decrease COUT or increase the tSS) or IOUT(oc) must be increased and a new value for RISNS calculated. IC(chg) = COUT ´ VOUT tSS (2) COUT ´ VOUT (IOUT(oc) - IEXT) tSS > where • • • • • • 14 IC(chg) is the output capacitor charging current in A COUT is the total output capacitance in F VOUT is the output voltage in V tSS is the soft-start time from Equation 1 IOUT(oc) is the desired over current trip point in A IEXT is any external load current in A Submit Documentation Feedback (3) Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 Feature Description (continued) The capacitor on the SS pin (CSS) also plays a role in overcurrent functionality. It is used as the timer between restart attempts. The SS pin is connected to GND through a resistor, RSS(dchg), whenever the controller senses an overcurrent condition. Switching stops and nothing else happens until the SS pin discharges to the soft-start reset threshold, VSS(rst). At this point, the SS pin capacitor is allowed to charge again through the charging resistor RSS(chg), and the controller restarts from that point. The shortest time between restart attempts occurs when the SS pin discharges from VSS(ofst) (approximately 700 mV) to VSS(rst) (150 mV) and then back to VSS(ofst) and switching resumes. In actuality, this is a conservative estimate since switching does not resume until the VSSE ramp rises to a point where it is commanding more output voltage than exists at the output of the controller. This occurs at some SS pin voltage greater than VSS(ofst) and depends on the voltage that remains on the output overvoltage the converter while switching has been halted. The fastest restart time can be calculated by using Equation 4, Equation 5, and Equation 6. æ VSS(ofst) tDCHG = RSS(dchg) ´ CSS ´ ln ç ç VSS(rst) è ( ( ö ÷ ÷ ø (4) ) ö÷ )÷ø æ V -V BP SS(rst) tCHG = RSS(chg) ´ CSS ´ ln ç ç V -V SS(ofst) è BP (5) tRSTRT(min ) = tCHG + tDCHG (6) VBP VSS tRSTR(min) VSS(ofst) VSS(rst) T - Time Figure 22. Soft Start during Overcurrent 7.3.2 BP Regulator The TPS40210 and TPS40211 have an on-board linear regulator that supplies power to the internal circuitry of the controller, including the gate driver. This regulator has a nominal output voltage of 8 V and must be bypassed with a 1-μF capacitor. If the voltage at the VDD pin is less than 8 V, the voltage on the BP pin will also be less and the gate drive voltage to the external FET is reduced from the nominal 8 V. This should be considered when choosing a FET for the converter. Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 15 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com Feature Description (continued) Connecting external loads to this regulator can be done, but care must be taken to ensure that the thermal rating of the device is observed since there is no thermal shutdown feature in this controller. Exceeding the thermal ratings causes out of specification behavior and can lead to reduced reliability. The controller dissipates more power when there is an external load on the BP pin and is tested for dropout voltage for up to 5-mA load. When the controller is in the disabled state, the BP pin regulator also shuts off so loads connected there power down as well. When the controller is disabled with the DIS/EN pin, this regulator is turned off. The total power dissipation in the controller can be calculated as follows. The total power is the sum of PQ, PG, and PE. PQ = VVDD ´ IVDD(en) (7) PG = VVDD ´ Qg ´ fSW (8) PE = VVDD ´ IEXT where • • • • • • • • PQ is the quiescent power of the device in W VDD is the VDD pin voltage in V IDD(en) is the quiescent current of the controller when enabled but not switching in A PG is the power dissipated by driving the gate of the FET in W Qg is the total gate charge of the FET at the voltage on the BP pin in C f SW is the switching frequency in Hz PE is the dissipation caused be external loading of the BP pin in W IEXT is the external load current in A (9) 7.3.3 Shutdown (DIS/EN Pin) The DIS/EN pin is an active high shutdown command for the controller. Pulling this pin above 1.2 V causes the controller to completely shut down and enter a low current consumption state. In this state, the regulator connected to the BP pin is turned off. There is an internal 1.1-MΩ pulldown resistor connected to this pin that keeps the pin at GND level when left floating. If this function is not used in an application, it is best to connect this pin to GND. 7.3.4 Minimum On-Time and Off-Time Considerations The TPS40210 has a minimum off-time of approximately 200 ns and a minimum on-time of 300 ns. These two constraints place limitations on the operating frequency that can be used for a given input-to-output conversion ratio. See Figure 2 for the maximum frequency that can be used for a given duty cycle. The duty cycle at which the converter operates is dependent on the mode in which the converter is running. If the converter is running in discontinuous conduction mode, the duty cycle varies with changes to the load much more than it does when running in continuous conduction mode. In continuous conduction mode, the duty cycle is related primarily to the input and output voltages. VOUT + VD 1 = VIN 1- D æ æ VIN D = ç1 - ç ç V è è OUT + VD (10) öö ÷ ÷÷ øø (11) In discontinuous mode, the duty cycle is a function of the load, input and output voltages, inductance, and switching frequency. D= 16 2 ´ (VOUT + VD )´ IOUT ´ L ´ fSW (VIN )2 Submit Documentation Feedback (12) Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 Feature Description (continued) All converters using a diode as the freewheeling or catch component have a load current level at which they transition from discontinuous conduction to continuous conduction. This is the point where the inductor current just falls to zero. At higher load currents, the inductor current does not fall to zero but remains flowing in a positive direction and assumes a trapezoidal wave shape as opposed to a triangular wave shape. This load boundary between discontinuous conduction and continuous conduction can be found for a set of converter parameters as follows. 2 VOUT + VD - VIN )´ (VIN ) ( IOUT(crit) = 2 2 ´ (VOUT + VD ) ´ fSW ´ L (13) For loads higher than the result of Equation 13, the duty cycle is given by Equation 11 and for loads less that the results of Equation 13, the duty cycle is given Equation 12. For Equations 1 through 4, the variable definitions are as follows. • VOUT is the output voltage of the converter in V • VD is the forward conduction voltage drop across the rectifier or catch diode in V • VIN is the input voltage to the converter in V • IOUT is the output current of the converter in A • L is the inductor value in H • f SW is the switching frequency in Hz 7.3.5 Setting the Oscillator Frequency The oscillator frequency is determined by a resistor and capacitor connected to the RC pin of the TPS40210. The capacitor is charged to a level of approximately VDD/20 by current flowing through the resistor and is then discharged by a transistor internal to the TPS40210. The required resistor for a given oscillator frequency is found from either Figure 1 or Equation 14. RT = 1 5.8 ´ 10 -8 ´ fSW ´ C T + 8 ´ 10 - 10 2 ´ fSW + 1.4 ´ 10 -7 ´ fSW - 1.5 ´ 10 - 4 + 1.7 ´ 10 - 6 ´ C T - 4 ´ 10 - 9 ´ C T 2 where • • • RT is the timing resistance in kΩ f SW is the switching frequency in kHz CT is the timing capacitance in pF (14) For most applications, a capacitor in the range of 68 pF to 120 pF gives the best results. Resistor values should be limited to between 100 kΩ and 1 MΩ as well. If the resistor value falls below 100 kΩ, decrease the capacitor size and recalculate the resistor value for the desired frequency. As the capacitor size decreases below 47 pF, the accuracy of Equation 14 degrades and empirical means can be needed to fine tune the timing component values to achieve the desired switching frequency. 7.3.6 Synchronizing the Oscillator The TPS40210 and TPS40211 can be synchronized to an external clock source. Figure 23 shows the functional diagram of the oscillator. When synchronizing the oscillator to an external clock, the RC pin must be pulled below 150 mV for 20 ns or more. The external clock frequency must be higher than the free running frequency of the converter as well. When synchronizing the controller, if the RC pin is held low for an excessive amount of time, erratic operation can occur. The maximum amount of time that the RC pin should be held low is 50% of a nominal output pulse, or 10% of the period of the synchronization frequency. If the external clock signal cannot operate with a low enough duty cycle to limit the amount of time the RC pin is held low, a resistor and capacitor can be added at the gate of the synchronization MOSFET. The capacitor should be added in series with the gate of the MOSFET to AC couple the rising edge of the synchronization signal. The resistor should be added from the gate of the MOSFET to ground to turn off the MOSFET. Typical values for the resistor and capacitor are 220 pF and 1 kΩ. Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 17 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com Feature Description (continued) Under circumstances where the duty cycle is less than 50%, a Schottky diode connected from the RC pin to an external clock can be used to synchronize the oscillator. The cathode of the diode is connected to the RC pin. The trip point of the oscillator is set by an internal voltage divider to be 1/20 of the input voltage. The clock signal must have an amplitude higher than this trip point. When the clock goes low, it allows the reset current to restart the RC ramp, synchronizing the oscillator to the external clock. This provides a simple, single-component method for clock synchronization. VDD 8 VIN + RRC External Frequency Synchronization (optional) RC Q R Q CLK + 1 + CRC S 150 mV GND 5 TPS40210/11 UDG-08063 Figure 23. Oscillator Functional Diagram VDD Amplitude > VIN 8 VIN + 20 RRC Duty Cycle < 50% RC + CRC Q R Q CLK + 1 Frequency > Controller Frequency S 150 mV GND 5 TPS40210/11 UDG-08064 Figure 24. Diode Connected Synchronization 18 Submit Documentation Feedback Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 Feature Description (continued) 7.3.7 Current Sense and Overcurrent The TPS4021x is a current mode controller that uses a resistor in series with the source terminal power FET to sense current for both the current mode control and overcurrent protection. The device enters a current limit state if the voltage on the ISNS pin exceeds the current limit threshold voltage VISNS(oc) from the Electrical Characteristics. When this happens, the controller discharges the SS capacitor through a relatively high impedance and then attempts to restart. The amount of output current that causes this to happen is dependent on several variables in the converter. TPS40210/11 VIN 10 VDD TPS40210/11 RT L 1 RC 6 GND VOUT VDD 10 CT GDRV 8 ISNS 7 RIFLT UDG-07119 CIFLT GND RISNS 6 UDG-07120 Figure 25. Oscillator Components Figure 26. Current Sense Components The load current overcurrent threshold is set by proper choice of RISNS. If the converter is operating in discontinuous mode, the current sense resistor is found in Equation 15. RISNS = fSW ´ L ´ VISNS(oc) 2 ´ L ´ fSW ´ IOUT(oc) ´ (VOUT + VD - VIN ) (15) If the converter is operating in continuous conduction mode, RISNS can be found in Equation 16. RISNS = VISNS VISNS = æ IOUT ö æ IRIPPLE ö æ IOUT ö æ D ´ VIN ö + ç 1- D ÷ + ç 2 ÷ø çç (1 - D ) ÷÷ ç 2 ´ fSW ´ L ÷ è ø è ø è ø è where • • • • • • • • RISNS is the value of the current sense resistor in Ω VISNS(oc) is the overcurrent threshold voltage at the ISNS pin (from electrical specifications) D is the duty cycle (from Equation 11) fSW is the switching frequency in Hz VIN is the input voltage to the power stage in V (see text) L is the value of the inductor in H IOUT(oc) is the desired overcurrent trip point in A VD is the drop across the diode in Figure 26 Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback (16) 19 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com Feature Description (continued) The TPS40210 and TPS40211 have a fixed undervoltage lockout (UVLO) that allows the controller to start at a typical input voltage of 4.25 V. If the input voltage is slowly rising, the converter might have less than its designed nominal input voltage available when it has reached regulation. As a result, this can decrease the apparent current limit load current value and must be taken into consideration when selecting RISNS. The value of VIN used to calculate RISNS must be the value at which the converter finishes start-up. The total converter output current at start-up is the sum of the external load current and the current required to charge the output capacitor or capacitors. See the Soft Start section of this data sheet for information on calculating the required output capacitor charging current. The topology of the standard boost converter has no method to limit current from the input to the output in the event of a short circuit fault on the output of the converter. If protection from this type of event is desired, it is necessary to use some secondary protection scheme, such as a fuse, or rely on the current limit of the upstream power source. 7.3.8 Current Sense and Subharmonic Instability A characteristic of peak current mode control results in a condition where the current control loop can exhibit instability. This results in alternating long and short pulses from the pulse width modulator. The voltage loop maintains regulation and does not oscillate, but the output ripple voltage increases. The condition occurs only when the converter is operating in continuous conduction mode and the duty cycle is 50% or greater. The cause of this condition is described in the Modeling, Analysis and Compensation of the Current-Mode Converter Application Report. The remedy for this condition is to apply a compensating ramp from the oscillator to the signal going to the pulse width modulator. In the TPS40210 and TPS40211, the oscillator ramp is applied in a fixed amount to the pulse width modulator. The slope of the ramp is given in Equation 17. æV ö s e = fSW ´ ç VDD ÷ 20 è ø (17) To ensure that the converter does not enter into subharmonic instability, the slope of the compensating ramp signal must be at least half of the down slope of the current ramp signal. Since the compensating ramp is fixed in the TPS40210 and TPS40211, this places a constraint on the selection of the current sense resistor. The down slope of the current sense wave form at the pulse width modulator is described in Equation 18. m2 = A CS ´ RISNS ´ (VOUT + VD - VIN ) L (18) Since the slope compensation ramp must be at least half, and preferably equal to the down slope of the current sense waveform seen at the pulse width modulator, a maximum value is placed on the current sense resistor when operating in continuous mode at 50% duty cycle or greater. For design purposes, some margin should be applied to the actual value of the current sense resistor. As a starting point, the actual resistor chosen should be 80% or less that the value calculated in Equation 19. This equation calculates the resistor value that makes the slope compensation ramp equal to one half of the current ramp downslope. Values no more than 80% of this result would be acceptable. RISNS(max) = VVDD ´ L ´ fSW 60 ´ (VOUT + VD - VIN ) where • • • • • • • 20 Se is the slope of the voltage compensating ramp applied to the pulse width modulator in V/s f SW is the switching frequency in Hz VDD is the voltage at the VDD pin in V m2 is the down slope of the current sense waveform seen at the pulse width modulator in V/s RISNS is the value of the current sense resistor in Ω VOUT is the converter output voltage VIN is the converter power stage input voltage VD is the drop across the diode in Figure 26 Submit Documentation Feedback (19) Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 Feature Description (continued) It is possible to increase the voltage compensation ramp slope by connecting the VDD pin to the output voltage of the converter instead of the input voltage as shown in Figure 26. This can help in situations where the converter design calls for a large ripple current value in relation to the desired output current limit setting. NOTE Connecting the VDD pin to the output voltage of the converter affects the start-up voltage of the converter since the controller undervoltage lockout (UVLO) circuit monitors the VDD pin and senses the input voltage less the diode drop before start-up. The effect is to increase the start-up voltage by the value of the diode voltage drop. If an acceptable RISNS value is not available, the next higher value can be used and the signal from the resistor divided down to an acceptable level by placing another resistor in parallel with CIFLT. 7.3.9 Current Sense Filtering In most cases, a small filter placed on the ISNS pin improves performance of the converter. These are the components RIFLT and CIFLT in Figure 26. The time constant of this filter should be approximately 10% of the nominal pulse width of the converter. The pulse width can be found using Equation 20. tON = D fSW (20) The suggested time constant is then RIFLT ´ CIFLT = 0.1´ tON (21) The range of RIFLT should be from about 1 kΩ to 5 kΩ for best results. Higher values can be used but this raises the impedance of the ISNS pin connection more than necessary and can lead to noise pickup issues in some layouts. CIFLT should be located as close as possible to the ISNS pin as well to provide noise immunity. 7.3.10 Control Loop Considerations There are two methods to design a suitable control loop for the TPS4021x. The first and preferred if equipment is available is to use a frequency response analyzer to measure the open loop modulator and power stage gain and to then design compensation to fit that. The usage of these tools for this purpose is well documented with the literature that accompanies the tool and is not be discussed here. The second option is to make an initial guess at compensation, and then evaluate the transient response of the system to see if the compensation is acceptable to the application or not. For most systems, an adequate response can be obtained by simply placing a series resistor and capacitor (RFB and CFB) from the COMP pin to the FB pin as shown in Figure 27. The initial compensation selection can be done more accurately with aid of WEBENCH® to select the components or the average Spice model to simulate the open loop modulator and power stage gain. Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 21 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com Feature Description (continued) VIN TPS40210 1 RC 2 SS 3 DIS/EN L VOUT VDD 10 BP 9 GDRV 8 CHF CFB RFB COUT RIFLT 4 COMP 5 FB ISNS 7 GND 6 CIFLT ROUT RSENSE R1 R2 UDG-07177 Figure 27. Basic Compensation Network The natural phase characteristics of most capacitors used for boost outputs combined with the current mode control provide adequate phase margin when using this type of compensation. To determine an initial starting point for the compensation, the desired crossover frequency must be considered when estimating the control to output gain. The model used is a current source into the output capacitor and load. When using these equations, the loop bandwidth should be no more than 20% of the switching frequency, fSW. A more reasonable loop bandwidth would be 10% of the switching frequency. Be sure to evaluate the transient response of the converter over the expected load range to ensure acceptable operation. K CO = gM ´ ZOUT (fCO ) 0.13 ´ L ´ gM = (22) fSW ROUT (RISNS )2 ´ (120 ´ RISNS + L ´ fSW ) (23) (1+ (2p ´ f ´ R L ZOUT = ROUT ´ ( 2 ESR 2 ´ COUT ) 2 ) ) 2 1 + (ROUT ) + 2 ´ ROUT ´ RESR + (RESR ) ´ (2p ´ fL ´ COUT ) where • • • • • • 22 KCO is the control to output gain of the converter, in V/V gM is the transconductance of the power stage and modulator, in S ROUT is the output load equivalent resistance, in Ω ZOUT is the output impedance, including the output capacitor, in Ω RISNS is the value of the current sense resistor, in Ω L is the value of the inductor, in H Submit Documentation Feedback Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 Feature Description (continued) • • • • COUT is the value of the output capacitance, in F RESR is the equivalent series resistance of COUT, in Ω f SW is the switching frequency, in Hz f L is the desired crossover frequency for the control loop, in Hz (24) These equations assume that the operation is discontinuous and that the load is purely resistive. The gain in continuous conduction can be found by evaluating Equation 23 at the resistance that gives the critical conduction current for the converter. Loads that are more like current sources give slightly higher gains than predicted here. To find the gain of the compensation network required for a control loop of bandwidth fL, take the reciprocal of Equation 22. K COMP = 1 K CO (25) The GBWP of the error amplifier is only guaranteed to be at least 1.5MHz. If KCOMP multiplied by fL is greater than 750 kHz, reduce the desired loop crossover frequency until this condition is satisfied. This ensures that the high-frequency pole from the error amplifier response with the compensation network in place does not cause excessive phase lag at fL and decreased phase margin in the loop. The RC network connected from COMP to FB places a zero in the compensation response. That zero should be approximately 1/10th of the desired crossover frequency, fL. With that being the case, RFB and CFB can be found from Equation 26 and Equation 27. RFB = CFB = R1 = R1´ K COMP K CO (26) 10 2p ´ fL ´ RFB where • • R1 is the high side feedback resistor in Figure 27, in Ω fL is the desired loop crossover frequency, in Hz (27) Thought not strictly necessary, it is recommended that a capacitor be added between COMP and FB to provide high-frequency noise attenuation in the control loop circuit. This capacitor introduces another pole in the compensation response. The allowable location of that pole frequency determines the capacitor value. As a starting point, the pole frequency should be 10 × fL. The value of CHF can be found from Equation 28. CHF = 1 20p ´ fL ´ RFB (28) While the error amplifier GBWP will usually be higher, it can be as low as 1.5MHz. If 10 × KComp × fL > 1.5MHz, the error amplifier gain-bandwidth product may limit the high-frequency response below that of the highfrequency capacitor. To maintain a consistent high-frequency gain roll-off, CHF can be calculated by Equation 29. CHF = 1 6 2p ´ 1.5 ´ (10 ) ´ RFB where • • CHF is the high-frequency roll-off capacitor value in F RFB is the mid band gain setting resistor value in Ω Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 (29) Submit Documentation Feedback 23 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com Feature Description (continued) 7.3.11 Gate Drive Circuit Some applications benefit from the addition of a resistor connected between the GDRV pin and the gate of the switching MOSFET. In applications that have particularly stringent load regulation (under 0.75%) requirements and operate from input voltages above 5 V, or are sensitive to pulse jitter in the discontinuous conduction region, this resistor is recommended. The recommended starting point for the value of this resistor can be calculated from Equation 30. RG = 105 QG where • • QG is the MOSFET total gate charge at 8 V, VGS in nC RG is the suggested starting point gate resistance in Ω (30) VIN TPS40210/11 L VDD 10 VOUT RG GDRV 8 ISNS 7 GND 6 UDG-07196 Figure 28. Gate Drive Resistor 7.3.12 TPS40211 The only difference between the TPS40210 and the TPS40211 is the reference voltage that the error amplifier uses to regulate the output voltage. The TPS40211 uses a 260-mV reference and is intended for applications where the output is actually a current instead of a regulated voltage. A typical example of an application of this type is an LED driver. An example schematic is shown in Figure 29. 24 Submit Documentation Feedback Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 Feature Description (continued) VIN IOUT TPS40210/11 1 RC 2 SS 3 DIS/EN L VDD 10 BP 9 GDRV 8 4 COMP ISNS 7 5 FB GND RIFB 6 UDG-07197 Figure 29. Typical LED Drive Schematic The current in the LED string is set by the choice of the resistor RISNS as shown in Equation 31. RIFB = VFB IOUT where • • • RIFB is the value of the current sense resistor for the LED string in Ω VFB is the reference voltage for the TPS40211 in V (0.260 V typ.) IOUT is the desired DC current in the LED string in A (31) 7.4 Device Functional Modes 7.4.1 Operation Near Minimum Input Voltage The TPS4021x is designed to operate with input voltages above 4.5 V. The typical VDD UVLO threshold is 4.25 V and the device can operate at input voltages down to the UVLO voltage. At input voltages below the actual UVLO voltage, the device will not switch. When VVDD passes the UVLO threshold the device will become active. Switching is enabled and the soft-start sequence is initiated. The TPS4021x will ramp up the output voltage at the rate determined by the external capacitor at the SS pin. 7.4.2 Operation With DIS/EN Pin The DIS/EN pin has a 1.2-V typical threshold which can be used to disable the TPS4021x. With DIS/EN forced above this threshold voltage, the device is disabled and switching is inhibited even if VVDD is above its UVLO threshold. Hysteresis on the DIS/EN pin threshold gives a typical turnon threshold of 1.05 V. If the DIS/EN is left floating or is pulled below the 1.05-V threshold while VVDD is above its UVLO threshold, the device becomes active. Switching is enabled and the soft-start sequence is initiated. The TPS4021x will ramp up the output voltage at the rate determined by the external capacitor at the soft-start pin. Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 25 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com 8 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 8.1 Application Information The TPS4021x is a 4.5-V to 52-V low-side controller with an integrated gate driver for a low-side N-channel MOSFET. This device is typically used in a boost topology to convert a lower DC voltage to a higher DC voltage with a peak current limit set by an external current sense resistor. It can also be configured in a SEPIC, Flyback and LED drive applications. In higher current applications, the maximum current can also be limited by the thermal performance of the external MOSFET and rectifying diode switch. Use the following design procedure to select external components for the TPS4021x. The design procedure illustrates the design of a typical boost regulator with the TPS40210. Alternatively, use the WEBENCH software to generate a complete design. The WEBENCH software uses an iterative design procedure and accesses a comprehensive database of components when generating a design. 8.2 Typical Applications 8.2.1 12-V to 24-V Nonsynchronous Boost Regulator The following example illustrates the design process and component selection for a 12-V to 24-V nonsynchronous boost regulator using the TPS40210 controller. + + Figure 30. TPS40210 Design Example – 12 V to 24 V at 2 A 26 Submit Documentation Feedback Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 Typical Applications (continued) 8.2.1.1 Design Requirements Table 1. TPS40210 Design Example Specifications PARAMETER TEST CONDITIONS MIN TYP MAX UNIT INPUT CHARACTERISTICS VIN Input voltage IIN Input current 8 12 No load input current VIN(UVLO) 14 4.4 0.05 Input undervoltage lockout 4.5 V A V OUTPUT CHARACTERISTICS VOUT Output voltage 23.5 24.0 Line regulation 24.5 V 1% Load regulation 1% VOUT(ripple) Output voltage ripple 500 IOUT Output current IOCP Output overcurrent inception point 8 V ≤ VIN ≤ 14 V 0.1 1 2.0 3.5 mVPP A Transient response ΔI Load step Load slew rate Overshoot threshold voltage Settling time 1 A 1 A/μs 500 mV 5 ms 600 kHz SYSTEM CHARACTERISTICS fSW Switching frequency ηPK Peak efficiency VIN = 12 V 95% η Full load efficiency VIN = 12 V, IOUT = 2 A 94% TOP Operating temperature range 8 V ≤ VIN ≤ 14 V, IOUT ≤ 2 A 25 °C MECHANICAL DIMENSIONS W Width 1.5 L Length 1.5 h Height 0.5 inch 8.2.1.2 Detailed Design Procedure 8.2.1.2.1 Custom Design with WEBENCH Tools Click here to create a custom design using the TPS40210 device with the WEBENCH® Power Designer. 1. Start by entering your VIN, VOUT and IOUT requirements. 2. Optimize your design for key parameters like efficiency, footprint and cost using the optimizer dial and compare this design with other possible solutions from Texas Instruments. 3. WEBENCH Power Designer provides you with a customized schematic along with a list of materials with real time pricing and component availability. 4. In most cases, you will also be able to: – Run electrical simulations to see important waveforms and circuit performance, – Run thermal simulations to understand the thermal performance of your board, – Export your customized schematic and layout into popular CAD formats, – Print PDF reports for the design, and share your design with colleagues. 5. Get more information about WEBENCH tools at www.ti.com/webench. 8.2.1.2.2 Duty Cycle Estimation The duty cycle of the main switching MOSFET is estimated using Equation 32 and Equation 33. Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 27 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com Typical Applications (continued) DMIN » VOUT - VIN(max) + VFD DMAX » VOUT + VFD VOUT - VIN(m in) + VFD VOUT + VFD = = 24 V - 14 V + 0.5 V = 42.9% 24 V + 0.5 V (32) 24 V - 8 V + 0.5 V = 67.3% 24 V + 0.5 V (33) Using an estimated forward drop (VFD) of 0.5 V for a schottky rectifier diode, the approximate duty cycle is 42.9% (minimum) to 67.3% (maximum). 8.2.1.2.3 Inductor Selection The peak-to-peak ripple is chosen to be 30% of the maximum input current. IOUT(max) 2 IRIPPLE(max) = 0.3 ´ = 0.3 ´ = 1.05 A 1 - DMIN 1 - 0.429 28 Submit Documentation Feedback (34) Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 Typical Applications (continued) The minimum inductor size can be estimated using Equation 35. VIN(max) 1 14 V 1 LMIN » ´ DMIN ´ = ´ 0.429 ´ = 9.5 mH IRIPPLE(max) fSW 1.05 A 600kHz (35) The next higher standard inductor value of 10 μH is selected. The ripple current for nominal and minimum VIN is estimated by Equation 36 and Equation 37. V 1 12 V 1 IRIPPLE(Vintyp) » IN ´ D ´ = ´ 0.50 ´ = 1.02 A L fSW 10 mH 600kHz (36) V 1 8V 1 IRIPPLE(Vinmin) » IN ´ D ´ = ´ 0.673 ´ = 0.90 A L fSW 10 mH 600kHz (37) The worst case peak-to-peak ripple current occurs at 50% duty cycle (VIN = 12.25 V) and is estimated as 1.02 A. Worst case RMS current through the inductor is approximated by Equation 38. ILrms = (I ( ) ) + ( 2 L avg 1 I 12 RIPPLE ) 2 æ IOUT(max) » ç ç 1- D MAX è 2 ö ÷÷ + ø (112IRIPPLE(VINmin) ) 2 2 2 æ ö = ç ÷ + 1 0.673 è ø ((112)´ 0.90A ) 2 = 6.13 Arms (38) The worst case RMS inductor current is 6.13 Arms. The peak inductor current is estimated by Equation 39. IOUT(max) 2 ILpeak » + (12 )IRIPPLE(Vinmin) = + (12 )0.90 = 6.57 A 1 - DMAX 1 - 0.673 (39) A 10-μH inductor with a minimum RMS current rating of 6.13 A and minimum saturation current rating of 6.57 A must be selected. A TDK RLF12560T-100M-7R5 7.5-A 10-μH inductor is selected. This inductor power dissipation is estimated by Equation 40. 2 PL » (ILrms ) ´ DCR (40) The TDK RLF12560T-100M-7R5 12.4-mΩ DCR dissipates 466-mW of power. 8.2.1.2.4 Rectifier Diode Selection A low forward voltage drop schottky diode is used as a rectifier diode to reduce its power dissipation and improve efficiency. Using 80% derating on VOUT for ringing on the switch node, the rectifier diode minimum reverse breakdown voltage is given by Equation 41. V V(BR)R(min) ³ OUT = 1.25 ´ VOUT = 1.25 ´ 24 V = 30 V 0.8 (41) The diode must have reverse breakdown voltage greater than 30 V. The rectifier diode peak and average currents are estimated by Equation 42 and Equation 43. ID (avg ) » IOUT (m ax ) = 2 A (42) ID(peak ) = IL(peak ) = 6.57 A (43) The power dissipation in the diode is estimated by Equation 44. PD(max) » VFD ´ ID(avg) = 0.5 V ´ 2 A = 1W (44) For this design, the maximum power dissipation is estimated as 1 W. Reviewing 30-V and 40-V schottky diodes, the MBRS340T3, 40-V, 3-A diode in an SMC package is selected. This diode has a forward voltage drop of 0.48 V at 6 A, so the conduction power dissipation is approximately 960 mW, less than half its rated power dissipation. Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 29 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com Typical Applications (continued) 8.2.1.2.5 Output Capacitor Selection Output capacitors must be selected to meet the required output ripple and transient specifications. I ´D æ 2 A ´ 0.673 ö 1 1 COUT = 8 OUT ´ = 8ç = 36 mF ÷´ VOUT(ripple) fSW è 500mV ø 600kHz ESR = VOUT(ripple ) 7 7 500mV ´ = ´ = 96mW 8 IL(peak ) - IOUT 8 6.57 A - 2 A (45) (46) A Panasonic EEEFC1V330P 35-V 33-μF, 120-mΩ bulk capacitor and a 6.8-μF ceramic capacitor are selected to provide the required capacitance and ESR at the switching frequency. The combined capacitance of 39.8 μF and ESR of 60 mΩ are used in compensation calculations. 8.2.1.2.6 Input Capacitor Selection Since a boost converter has continuous input current, the input capacitor senses only the inductor ripple current. The input capacitor value can be calculated by Equation 47 and Equation 48. IRIPPLE 1.02 A CIN > = = 7.1mF 4 ´ VIN(ripple ) ´ fSW 4 ´ 60mV ´ 600kHz (47) ESR < VIN(ripple ) 2 ´ IRIPPLE = 60mV = 29mW 2 ´ 1.02 A (48) For this design to meet a maximum input ripple of 60 mV (1/2% of VIN nominal), a minimum 7.1-μF input capacitor with ESR less than 29 mΩ is needed. A 10-μF, X7R ceramic capacitor is selected. 8.2.1.2.7 Current Sense and Current Limit The maximum allowable current sense resistor value is limited by both the current limit and sub-harmonic stability. These two limitations are given by Equation 49 and Equation 50. VISNS(OC)MIN 120mV = = 15.4mW RISNS < 1.1´ (6.57 A + 0.50 A) 1.1´ IL(peak ) + IDrive ( RISNS < ) VIN(MAX) ´ L ´ fSW 60 ´ (VOUT + VFD - VIN ) (49) = 14 V ´ 10 mH ´ 600kHz = 134mW 60 ´ (24 V + 0.48 V - 14 V) (50) With 10% margin on the current limit trip point (the 1.1 factor) and assuming a maximum gate drive current of 500 mA, the current limit requires a resistor less than 15.4 mΩ and stability requires a sense resistor less than 134 mΩ. A 10-mΩ resistor is selected. Approximately 2 mΩ of routing resistance is added in compensation calculations. The power dissipation in RISNS is calculated by Equation 51. PRISNS = (ILRMS )2 × RISNS × D (51) At maximum duty cycle, this is 0.253 W. 8.2.1.2.8 Current Sense Filter To remove switching noise from the current sense, an RC filter is placed between the current sense resistor and the ISNS pin. A resistor with a value between 1 kΩ and 5 kΩ is selected and a capacitor value is calculated by Equation 52. 0.1´ DMIN 0.1´ 0.429 CIFLT = = = 71pF fSW ´ RIFLT 600kHz ´ 1kW (52) For a 1-kΩ filter resistor, 71 pF is calculated and a 100-pF capacitor is selected. 30 Submit Documentation Feedback Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 Typical Applications (continued) 8.2.1.2.9 Switching MOSFET Selection The TPS40210 drives a ground referenced N-channel FET. The RDS(on) and gate charge are estimated based on the desired efficiency target. æ1 ö æ1 ö æ 1 ö - 1÷ = 2.526 W PDISS(total) » POUT ´ ç - 1÷ = VOUT ´ IOUT ´ ç - 1÷ = 24 V ´ 2 A ´ ç è 0.95 ø èh ø èh ø (53) For a target of 95% efficiency with a 24-V input voltage at 2 A, maximum power dissipation is limited to 2.526 W. The main power dissipating devices are the MOSFET, inductor, diode, current sense resistor and the integrated circuit, the TPS40210. PFET < PDISS(total) - PL - PD - PRisns - VIN(max) ´ IVDD(max) (54) This leaves 812 mW of power dissipation for the MOSFET. This can likely cause an SO-8 MOSFET to get too hot, so power dissipation is limited to 500 mW. Allowing half for conduction and half for switching losses, we can determine a target RDS(on) and QGS for the MOSFET by Equation 55 and Equation 56. QGS < 3 ´ PFET ´ IDRIVE 3 ´ 0.50 W ´ 0.50 A = = 13.0nC 2 ´ VOUT ´ IOUT ´ fSW 2 ´ 24 V ´ 2 A ´ 600kHz (55) A target MOSFET gate-to-source charge of less than 13.0 nC is calculated to limit the switching losses to less than 250 mW. PFET 0.50 W RDS(on ) < = = 9.9mW 2 2 2 ´ (IRMS ) ´ D 2 ´ 6.13 ´ 0.673 (56) A target MOSFET RDS(on) of 9.9 mΩ is calculated to limit the conduction losses to less than 250 mW. Reviewing 30-V and 40-V MOSFETs, an Si4386DY 9-mΩ MOSFET is selected. A gate resistor was added per Equation 30. The maximum gate charge at VGS= 8V for the Si4386DY is 33.2 nC, this implies RG = 3.3 Ω. 8.2.1.2.10 Feedback Divider Resistors The primary feedback divider resistor (RFB) from VOUT to FB should be selected between 10 kΩ and 100 kΩ to maintain a balance between power dissipation and noise sensitivity. For a 24-V output, a high feedback resistance is desirable to limit power dissipation so RFB = 51.1 kΩ is selected. RBIAS = VFB ´ RFB 0.700 V ´ 51.1kW = = 1.53kW VOUT - VFB 24 V - 0.700 V (57) RBIAS = 1.50 kΩ is selected. 8.2.1.2.11 Error Amplifier Compensation Compensation selection can be done with aid of WEBENCH to select compensation components or with the aid of the average Spice model to simulate the open loop modulator and power stage gain. Alternatively, the following procedure gives a good starting point. While current mode control typically only requires Type II compensation, it is desirable to layout for Type III compensation to increase flexibility during design and development. Current mode control boost converters have higher gain with higher output impedance, so it is necessary to calculate the control loop gain at the maximum output impedance, estimated by Equation 58. ROUT(max ) = VOUT 24 V = = 240 W IOUT(min ) 0.1A Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 (58) Submit Documentation Feedback 31 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com Typical Applications (continued) The transconductance of the TPS40210 current mode control can be estimated by Equation 59. 0.13 ´ L ´ gM = fSW ROUT 0.13 ´ 10 mH ´ = 2 600kHz 240 W = 19.2 A 2 (RISNS ) ´ (120 ´ RISNS + L ´ fSW ) (12mW ) ´ (120 ´ 12mW + 10 mH ´ 600kHz ) V (59) The maximum output impedance ZOUT, can be estimated by Equation 60. (1+ (2p ´ f ´ R ) 1 + ((R ) + 2 ´ R ´ R + (R ) )´ (2p ´ f ´ C ) 1 + (2p ´ 30kHz ´ 60mW ´ 39.8 mF ) ) ( = 240 W ´ ) 1 + ((240 W ) + 2 ´ 240 W ´ 60mW + (60mW ) )´ (2p ´ 30kHz ´ 39.8 mF ) ESR ZOUT (f ) = ROUT ´ 2 ´ COUT ) 2 2 OUT OUT ESR 2 ESR OUT (60) 2 ZOUT (fL 2 2 2 = 0.146 W (61) At the desired crossover frequency (fL) of 30 kHz, ZOUT becomes 0.146 Ω. The modulator gain at the desired cross-over can be estimated by Equation 62. K CO = gM ´ ZOUT (fCO ) = 19.2 A ´ 0.146 W = 2.80 V (62) The feedback compensation network needs to be designed to provide an inverse gain at the cross-over frequency for unity loop gain. This sets the compensation mid-band gain at a value calculated in Equation 63. 1 1 K COMP = = = 0.357 K CO 2.80 (63) To set the mid-band gain of the error amplifier to KCOMP, use Equation 64. R4 = R7 ´ K COMP = R7 51.1kW = = 18.2kW K CO 2.80 (64) R4 = 18.7 kΩ selected. Place the zero at 1/10th of the desired cross-over frequency. C2 = 10 10 = = 2837pF 2p ´ fL ´ R4 2p ´ 30kHz ´ 18.7kW (65) C2 = 2200 pF selected. Place a high-frequency pole at about five times the desired cross-over frequency and less than one-half the unity gain bandwidth of the error amplifier: C4 » C4 > 1 1 = = 56.74pF 10p ´ fL ´ R4 10p ´ 30kHz ´ 18.7kW (66) 1 1 = = 11.35pF p ´ GBW ´ R4 p ´ 1.5MHz ´ 18.7kW (67) C4 = 47 pF selected. 8.2.1.2.12 RC Oscillator The RC oscillator calculation is given as shown in Equation 14 in the data sheet, substituting 100 for CT and 600 for fSW. For a 600-kHz switching frequency, a 100pF capacitor is selected and a 262-kΩ resistor is calculated (261-kΩ selected). 32 Submit Documentation Feedback Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 Typical Applications (continued) 8.2.1.2.13 Soft-Start Capacitor Since VDD > 8 V, the soft-start capacitor is selected by using Equation 68 to calculate the value. CSS = 20 ´ TSS ´ 10-6 (68) For TSS = 12 ms, CSS = 240 nF. A 220-nF capacitor is selected. 8.2.1.2.14 Regulator Bypass A regulator bypass (BP) capacitor of 1.0 μF is selected per the datasheet recommendation. 8.2.1.2.15 Bill of Materials Table 2. Bill of Materials REFERENCE DESIGNATOR DESCRIPTION SIZE PART NUMBER MANUFACTURER 0.406 x 0.457 EEEFC1V101P Panasonic C1 100 μF, aluminum capacitor, SM, ± 20%, 35 V C2 2200 pF, ceramic capacitor, 25 V, X7R, 20% 0603 Std Std C3 100 pF, ceramic capacitor, 16 V, C0G, 10% 0603 Std Std C4 47 pF, ceramic capacitor, 16V, X7R, 20% 0603 Std Std C5 0.22 μF, ceramic capacitor, 16 V, X7R, 20% 0603 Std Std C7 1.0 μF, ceramic capacitor, 16 V, X5R, 20% 0603 Std Std C8 10 μF, ceramic capacitor, 25 V, X7R, 20% 0805 C3225X7R1E106M TDK C9 0.1 μF, ceramic capacitor, 50 V, X7R, 20% 0603 Std Std C10 100 pF, ceramic capacitor, 16 V, X7R, 20% 0603 Std Std D1 Schottky diode, 3 A, 40 V SMC MBRS340T3 On Semi L1 10 μH, inductor, SMT, 7.5 A, 12.4 mΩ 0.325 x 0.318 inch RLF12560T-100M-7R5 TDK Q1 MOSFET, N-channel, 40 V, 14 A, 9mΩ SO-8 Si4840DY Vishay R3 10 kΩ, chip resistor, 1/16 W, 5% 0603 Std Std R4 18.7 kΩ, chip resistor, 1/16 W, 1% 0603 Std Std R5 1.5 kΩ, chip resistor, 1/16 W, 1% 0603 Std Std R6 261 kΩ, chip resistor, 1/16 W, 1% 0603 Std Std R7 51.1 kΩ, chip resistor, 1/16 W, 1% 0603 Std Std R9 3.3 Ω, chip resistor, 1/16 W, 5% 0603 Std Std R10 1.0 kΩ, chip resistor, 1/16 W, 5% 0603 Std Std R11 10 mΩ, chip resistor, 1/2 W, 2% 1812 Std Std U1 IC, 4.5 V-52 V I/P, current mode boost controller DGQ10 TPS40210DGQ TI Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 33 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com 8.2.1.3 Application Curves 80 180 60 135 VIN = 8 V VOUT = 24 V IOUT = 2 A 40 90 20 45 0 0 Gain -20 -45 -40 -90 -60 -135 -80 100 FET Vds (20 V/ div) -180 1M 1000 10 k 100 k fSW – Frequency – Hz T – Time – 400 ns Figure 32. FET VDS and VGS Voltages vs Time Figure 31. Gain and Phase vs Frequency 6 100 96 5 94 92 VIN = 12 V 90 88 VIN (V) 14 12 8 VIN = 14V PLOSS – Power Loss – W VIN (V) 14 12 8 98 h – Efficiency – % GDRV (5 V/ div) Phase – ° Gain – dB Phase VIN = 8 V 86 VIN = 8 V 4 VIN = 12 V 3 2 VIN = 14 V 84 1 82 80 0 0 0.5 1.0 1.5 2.0 ILOAD – Load Current – A 0 2.5 Figure 33. Efficiency vs Load Current 0.5 1.0 1.5 2.0 ILOAD – Load Current – A 2.5 Figure 34. Power Loss vs Load Current 24.820 VOUT – Output Voltage – V 24.772 24.724 VIN (V) 14 12 8 VIN = 8 V 24.676 24.628 24.580 VIN = 14 V 24.532 VIN = 12 V 24.484 24.436 24.388 24.340 0 0.5 1.0 1.5 2.0 ILOAD – Load Current – A 2.5 Figure 35. Output Voltage vs Load Current 34 Submit Documentation Feedback Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 8.2.2 12-V Input, 700-mA LED Driver, Up to 35-V LED String This application uses the TPS40211 as a boost controller that drives a string of LED diodes. The feedback point for this circuit is a sense resistor in series with this string. The low 260-mV reference minimizes power wasted in this resistor, and maintains the LED current at a value given by 0.26/R6. As the input voltage is varied, the duty cycle changes to maintain the LED current at a constant value so that the light intensity does not change with large input voltage variations. L1 VIN C21 C1 GDRV C2 D1 B2100 Q1 R2 ISNS C3 R1 R11 C4 VIN R3 D2 C8 1 U1 TPS40211 RC VIN 10 C10 C9 Loop Response Injection C6 R23 R13 R4 DIS/EN C11 2 SS BP 9 3 DIS/EN GDRV 8 4 COMP ISNS 7 5 FB GND 6 C5 LEDC GDRV LEDC ISNS R24 C13 R6 D3 R15 Q3 C14 PWM Dimming UDG-08015 Figure 36. 12-V Input, 700-mA LED Driver, Up to 35-V LED String 8.2.2.1 Design Requirements Table 3. TPS40211 Design Example Specifications PARAMETER MIN TYP MAX UNIT 8 12 20 V 35 V INPUT CHARACTERISTICS VIN Input voltage OUTPUT CHARACTERISTICS VOUT Output voltage IOUT Output current 0.7 A 400 kHz SYSTEM CHARACTERISTICS fSW Switching frequency Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 35 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com 8.2.2.2 Detailed Design Procedure Table 4. TPS40211 LED Driver Bill of Materials REFERENCE DESIGNATOR TYPE DESCRIPTION SIZE C1,C2 10 μF, 25 V 1206 C3, C4 2.2 μF, 100 V 1210 C5 1 nF, NPO 0603 C6 100 pF, NPO 0603 C8 100 pF 0603 0.1 μF 0603 C10 0.1 μF, 25 V 0805 C11 1 μF, 25 V 1206 C13 220 pF 0603 C14 10 nF, X7R 0603 C21 330 μF, 25 V electrolytic D1 B2100, SHTKY, 100 V, 2 A C9 D2 Capacitor Diode D3 L1 Q1 Q3 SMB BZT52C43 SOD-123 MMBD7000 Inductor MOSFET SOT-23 Wurth 7447709100, 10 μH, 6 A 12mm × 12mm × 10mm Si7850DP, 60 V, 31 mΩ SO-8 2N7002, 60 V, 0.1 A SOT-23 R1 15 mΩ 2512 R2 3.01 Ω 0805 R3 402 kΩ 0603 R4 14.3 kΩ 0603 R6 0.36 Ω 2512 R11 Resistor 1 kΩ 0603 R13 30.1 kΩ 0603 R15 49.9 kΩ 0603 R24 10 kΩ 0603 10 Ω R23 U1 36 Integrated circuit Submit Documentation Feedback 0603 TPS40211 DRC-10 Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 9 Power Supply Recommendations The TPS4021x is designed to operate from an input voltage supply range between 4.5 V and 52 V. This input supply should remain within the input voltage range of the TPS4021x. If the input supply is located more than a few inches from the buck power stage controlled by the TPS4021x, additional bulk capacitance can be required in addition to ceramic-bypass capacitors. An electrolytic capacitor with a value of 100 µF is a typical choice. 10 Layout 10.1 Layout Guidelines • • • • • • • • • For the maximum effectiveness from C9, place it near the VDD pin of the controller. Excessive high frequency noise on VDD during switching degrades overall regulation as the load increases. Keep the output loop (Q1-D1-C12-R11) as small as possible. A larger loop can degrade current limit accuracy and increase rediated emissions. For best current limit accuracy keep the ISNS filter components C10 and R10 near the ISNS and GND pins. Avoid connecting traces carrying large AC currents through a ground plane. Instead, use PCB traces on the top layer to conduct the AC current and use the ground plane as a noise shield. Split the ground plane as necessary to keep noise away from the TPS4021x and noise sensitive areas such as components connected to the RC pin, FB pin, COMP pin, and SS pin. Also keep these noise sensitive components close to the TPS4021x IC. Keep C7 near the BP and GND pins to provide good bypass for the BP regulator. The GDRV trace should be as close as possible to the power FET gate to minimize parisitic resistance and inductance in the trace. The parasitics should also be minimized in the return path from the source of the MOSFET, through the sense resistor and back to the GND pin. Keep the SW node as physically small as possible to minimize parasitic capacitance and radiated emissions. For good output voltage regulation, Kelvin connections should be brought from the load to the top FB resistor R7. 10.2 Layout Example Figure 37. Component Placement Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 37 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com Layout Example (continued) Figure 38. Top Copper Figure 39. Bottom Copper Viewed From Top 38 Submit Documentation Feedback Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 Layout Example (continued) Figure 40. Internal 1 Copper Viewed From Top Figure 41. Internal 2 Copper Viewed From Top Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 39 TPS40210, TPS40211 SLUS772G – MARCH 2008 – REVISED JUNE 2020 www.ti.com 11 Device and Documentation Support 11.1 Device Support 11.1.1 Third-Party Products Disclaimer TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE. • Design and Application Guide for High Speed MOSFET Gate Drive Circuits, SEM 1400, 2001 Seminar Series • Designing Stable Control Loops, SEM 1400, 2001 Seminar Series 11.1.2 Related Devices The following devices have characteristics similar to the TPS40210 and may be of interest. Table 5. Related Parts DEVICE DESCRIPTION TPS6100x Single- and Dual-Cell Boost Converter with Start-up into Full Load TPS6101x High Efficiency 1-Cell and 2-Cell Boost Converters TPS6300x High Efficiency Single Inductor Buck-Boost Converter with 1.8A Switches 11.1.3 Development Support 11.1.3.1 Custom Design with WEBENCH Tools Click here to create a custom design using the TPS40210 device with the WEBENCH® Power Designer. 1. Start by entering your VIN, VOUT and IOUT requirements. 2. Optimize your design for key parameters like efficiency, footprint and cost using the optimizer dial and compare this design with other possible solutions from Texas Instruments. 3. WEBENCH Power Designer provides you with a customized schematic along with a list of materials with real time pricing and component availability. 4. In most cases, you will also be able to: – Run electrical simulations to see important waveforms and circuit performance, – Run thermal simulations to understand the thermal performance of your board, – Export your customized schematic and layout into popular CAD formats, – Print PDF reports for the design, and share your design with colleagues. 5. Get more information about WEBENCH tools at www.ti.com/webench. 11.2 Documentation Support 11.2.1 Related Documentation These references may be found on the web at www.power.ti.com under Technical Documents. Many design tools and links to additional references, may also be found at www.power.ti.com. • PowerPAD™ Thermally Enhanced Package • PowerPAD™ Made Easy • AC-DC Non-Isolated SMPS for Single-Phase Smart Meters Based on UCC28722 11.3 Related Links The table below lists quick access links. Categories include technical documents, support and community resources, tools and software, and quick access to sample or buy. 40 Submit Documentation Feedback Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 TPS40210, TPS40211 www.ti.com SLUS772G – MARCH 2008 – REVISED JUNE 2020 Related Links (continued) Table 6. Related Links PARTS PRODUCT FOLDER SAMPLE & BUY TECHNICAL DOCUMENTS TOOLS & SOFTWARE SUPPORT & COMMUNITY TPS40210 Click here Click here Click here Click here Click here TPS40211 Click here Click here Click here Click here Click here 11.4 Receiving Notification of Documentation Updates To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper right corner, click on Alert me to register and receive a weekly digest of any product information that has changed. For change details, review the revision history included in any revised document. 11.5 Trademarks WEBENCH is a registered trademark of Texas Instruments. All other trademarks are the property of their respective owners. 11.6 Electrostatic Discharge Caution This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. 11.7 Glossary SLYZ022 — TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. Copyright © 2008–2020, Texas Instruments Incorporated Product Folder Links: TPS40210 TPS40211 Submit Documentation Feedback 41 PACKAGE OPTION ADDENDUM www.ti.com 13-Aug-2021 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) (4/5) (6) TPS40210DGQ ACTIVE HVSSOP DGQ 10 80 RoHS & Green NIPDAU | NIPDAUAG Level-1-260C-UNLIM -40 to 125 40210 TPS40210DGQG4 ACTIVE HVSSOP DGQ 10 80 RoHS & Green Level-1-260C-UNLIM -40 to 125 40210 TPS40210DGQR ACTIVE HVSSOP DGQ 10 2500 RoHS & Green NIPDAU | NIPDAUAG Level-1-260C-UNLIM -40 to 125 40210 TPS40210DGQRG4 ACTIVE HVSSOP DGQ 10 2500 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 125 40210 TPS40210DRCR ACTIVE VSON DRC 10 3000 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 125 4210 TPS40210DRCT ACTIVE VSON DRC 10 250 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 125 4210 TPS40211DGQ ACTIVE HVSSOP DGQ 10 80 RoHS & Green NIPDAU | NIPDAUAG Level-1-260C-UNLIM -40 to 125 40211 TPS40211DGQR ACTIVE HVSSOP DGQ 10 2500 RoHS & Green NIPDAU | NIPDAUAG Level-1-260C-UNLIM -40 to 125 40211 TPS40211DRCR ACTIVE VSON DRC 10 3000 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 125 4211 TPS40211DRCRG4 ACTIVE VSON DRC 10 3000 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 125 4211 TPS40211DRCT ACTIVE VSON DRC 10 250 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 125 4211 NIPDAU (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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