MP28167GQ-P

MP28167 2.8V-22V VIN, 3A IOUT, 4-Switch Integrated Buck-Boost Converter with Fixed 5V Output DESCRIPTION FEATURES The MP28167 is a synchronous, 4-switch, integrated buck-boost converter, capable of regulating the output voltage across a 2.8V to 22V wide input voltage range with high efficiency.  The MP28167 uses constant-on-time control in buck mode and constant-off-time control in boost mode, providing fast load transient response as well as smooth buck-boost mode transient. The MP28167 provides forced PWM switching mode and programmable output CC (constant current) limit, which supports flexible design for different applications. Full protection features include over-current protection (OCP), over-voltage protection (OVP), under-voltage protection (UVP), and thermal shutdown. Wide 2.8V to 22V Operating Input Voltage Range Fixed 5V Output Voltage 3A Output Current or 4A Input Current 130mV Line Drop Compensation 500kHz Fixed Switching Frequency Forced PWM Switching Mode Four Low RDS(ON) Internal Buck Power MOSFETs Adjustable Accurate CC Output Current Limit with Internal Sensing FET Output Over-Voltage Hiccup Protection Output Short-Circuitry Hiccup Protection Over-Temperature Shutdown EN Shutdown Discharge Function Available in a QFN-16 (3mmx3mm) Package             APPLICATIONS The MP28167 is available in a 16-pin QFN (3mmx3mm) package.  Buck-Boost Bus Supply All MPS parts are lead-free, halogen free, and adhere to the RoHS directive. For MPS green status, please visit the MPS website under Quality Assurance. “MPS,” the MPS logo, and “Simple, Easy Solutions” are registered trademarks of Monolithic Power Systems, Inc. or its subsidiaries. TYPICAL APPLICATION Efficiency vs. Output Current C4 100nF BST1 SW1 IN C1 100µF BST2 C1A 22µF C5 95 100nF SW2 R3 499k VOUT OUT EN C2A 10µFx2 MP28167 C7 22nF NC NC RSV1 RSV2 VCC C3 1µF AGND GND R1 21.5k MP28167 Rev 1.0 4/29/2019 100 4.7µH OC + C2 100µF EFFICIENCY (%) VIN 12V + VIN = 12V, VOUT = 5V, L = 4.7µH, RDC = 19.7mΩ L1 90 85 80 75 70 65 C6 22nF 60 0.01 0.1 1 OUTPUT CURRENT (A) www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 10 1 MP28167 – 22V VIN, 3A IOUT INTEGRATED BUCK-BOOST CONVERTER ORDERING INFORMATION Part Number* Package Top Marking MP28167GQ QFN-16 (3mmx3mm) See Below * For Tape & Reel, add suffix –Z (e.g. MP28167GQ–Z). TOP MARKING BJH: Product code of MP28167GQ Y: Year code LLL: Lot number PACKAGE REFERENCE TOP VIEW BST1 SW1 16 IN SW2 BST2 OUT 1 GND GND EN AGND NC VCC RSV1 RSV2 OC NC QFN-16 (3mmx3mm) MP28167 Rev 1.0 4/29/2019 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 2 MP28167 – 22V VIN, 3A IOUT INTEGRATED BUCK-BOOST CONVERTER PIN FUNCTIONS Pin # Name 1 IN 2, 11 GND 3 EN 4, 8 5 6 7 9 10 12 NC RSV1 RSV2 OC VCC AGND OUT 13 BST2 14 SW2 15 SW1 16 BST1 MP28167 Rev 1.0 4/29/2019 Description Supply voltage. IN is the drain of the internal power device and provides power to the entire chip. The MP28167 operates from a 2.8V to 22V input voltage. A capacitor (CIN) is required to prevent large voltage spikes from appearing at the input. Place CIN as close to the IC as possible. Power ground. GND is the reference ground of the regulated output voltage. GND requires extra care during PCB layout. Connect GND with copper traces and vias. On/off control for entire chip. Drive EN high to turn on the chip. Drive EN low or float EN to turn off the device. EN has an internal 2MΩ pull-down resistor to ground. No connection. These pins should be connected to GND. Reserved pin. This pin cannot be floated. It can be tied to GND or VCC. Reserved pin. This pin cannot be floated. It can be tied to GND or VCC. Output constant current limit set pin. Internal 3.65V LDO regulator output. Decouple VCC with a 1µF capacitor. Analog ground. Connect AGND to GND. Output power pin. Place the output capacitor close to OUT and GND. Bootstrap. Connect a 0.1µF capacitor between SW2 and BST2 to form a floating supply across the high-side switch driver. Switching node of the second half-bridge. Connect one end of the inductor to SW2 for the current to run through the bridge. Switching node of the first half-bridge. Connect one end of the inductor to SW1 for the current to run through the bridge. Bootstrap. Connect a 0.1µF capacitor between SW1 and BST1 to form a floating supply across the high-side switch driver. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 3 MP28167 – 22V VIN, 3A IOUT INTEGRATED BUCK-BOOST CONVERTER θJA θJC ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance Supply voltage (VIN, VOUT) ............................ 24V VSW1, SW2 .............................................................. -0.3V (-7V for VOUT) When the input voltage is significantly higher than the output voltage, the MP28167 works in buck mode. In buck mode, SWA and SWB switch for the buck regulation, while SWC is off MP28167 Rev 1.0 4/29/2019 Figure 5: Boost Waveform www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 13 MP28167 – 22V VIN, 3A IOUT INTEGRATED BUCK-BOOST CONVERTER Buck-Boost Mode (VIN ≈ VOUT) When VIN is close to VOUT, the converter may not be able to provide enough energy to work in buck mode due to SWA’s minimum off time, or the converter may supply too much power to VOUT in boost mode due to SWC’s minimum on time. The MP28167 uses buck-boost control to regulate the output in these conditions. In buck mode, if VIN drops and the SWA off period is close to the buck minimum off time, buck-boost mode is engaged. When the next cycle starts after the SWA and SWD on period (buck HS-FET on period), boost starts with SWA and SWC on (boost LS-FET on). Then, SWA and SWD turn on again for the rest of the boost period (boost HS-FET on). After the boost period elapses, the buck period starts and SWB and SWD remain on until the inductor current drops to the COMP voltage. Then SWA and SWD turn on until next the boost period starts. This repeated process in which the buck and boost switching work with one interval period is called buck-boost mode. In boost mode, if VIN rises and the SWC on period is close to the boost minimum on time, buck-boost mode is engaged. After the boost constant-off-time period (SWA and SWD on), SWB and SWD remain on until the inductor current signal drops to the COMP voltage, just like a buck off period control. After the inductor current signal triggers the COMP voltage, SWA and SWD turn on for the buck on time, which is followed by one boost switching (SWA and SWC on), and buck and boost repeat switching work with one interval. Figure 6 shows the buck-boost waveform for both VIN > VOUT and VIN < VOUT conditions. SW1 tBoo st-Min SW2 Buck min off time IL COMP Buck Buck-Boo st tBuck-Boo st SW1 tBuck-Min SW2 Boo st min on time COMP IL Boo st Buck-Boo st tBuck-Boo st (b) Boost to Buck-Boost Transient Figure 6: Buck-Boost Waveform In buck-boost mode, if VIN exceeds 130% of VOUT, the MP28167 shifts from buck-boost mode to buck mode. If VIN is below 20% of VOUT, it shifts from buck-boost mode to boost mode. Working Mode – FCCM (or Forced PWM) Mode The MP28167 works in forced PWM mode with fixed frequency. In FCCM conditions, the buck on time and boost off time are determined by an internal circuit to get a fixed frequency based on the VIN/VOUT ratio. When the load decreases, the average input current drops and the inductor current may go to negative from VOUT to VIN during the off time (SWD on). This forces the inductor current to work in continuous mode with fixed frequency, and can produce a lower VOUT ripple. Internal VCC Regulator The 3.65V internal regulator powers most of the internal circuitries. This regulator takes VIN and operates in the full VIN range. When VIN exceeds 3.65V, the output of the regulator is in full regulation. If VIN is less than 3.65V, the output decreases with VIN. The VCC requires an external 1µF ceramic decoupling capacitor. Enable Control (EN) The MP28167 has an enable control (EN). Pull EN high to enable the IC. Pull EN low or float to disable the IC. Under-Voltage Lockout (UVLO) Under-voltage lockout (UVLO) protects the chip from operating at an insufficient supply voltage. The UVLO comparator monitors the input voltage, and enables or disables the whole IC. (a) Buck to Buck-Boost Transient MP28167 Rev 1.0 4/29/2019 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 14 MP28167 – 22V VIN, 3A IOUT INTEGRATED BUCK-BOOST CONVERTER Internal Soft Start (SS) The soft start (SS) prevents the converter output voltage from overshooting during start-up. When the chip starts up, the internal circuitry generates a SS voltage that ramps up from 0V to 3.65V. When SS is lower than VREF, the error amplifier uses SS as the reference. When SS is higher than VREF, the error amplifier uses VREF as the reference. If the output of the MP28167 is pre-biased to a certain voltage during start-up, the IC disables the switching of both the high-side and low-side switches until the voltage on the internal SS capacitor exceeds the internal feedback voltage (see Figure 7). EN 90% VOUT tDELA Y Figure 7: EN On to VOUT > 90% Delay Output Constant Current Limit (OCP) The MP28167 has a constant current limit control loop to limit the output average current. The current information is sensed from switches A, B, C, and D. Then an average algorithm is used to calculate the output current. When the output current exceeds the currentlimit threshold, the output voltage starts to drop. If VOUT drops below the under-voltage (UV) threshold (typically 50% below the reference), the MP28167 enters hiccup mode. The part stops switching and recovers automatically with 12.5% duty cycles. Over-Voltage Protection (OVP) The MP28167 monitors a resistor-divided feedback voltage to detect output over-voltage. When the feedback voltage exceeds 160% of the MP28167 Rev 1.0 4/29/2019 target voltage, the OVP comparator output goes high and the output to ground discharge resistor turns on. The OUT pin has an absolute OVP function. Once the OUT voltage exceeds the absolute OVP threshold (23V), the MP28167 stops switching and turns on the output to ground discharge resistor. Start-Up and Shutdown If both VIN and EN exceed their respective thresholds, the chip is enabled. The reference block starts first, generating a stable reference voltage and current, and then the internal regulator is enabled. The regulator provides a stable supply for the remaining circuitries. Several events can shut down the chip: EN low, VIN low, and thermal shutdown. In shutdown, the signaling path is blocked to avoid any fault triggering. Then the COMP voltage and the internal supply rails are pulled down. The floating driver is not subject to this shutdown command. Output Discharge The MP28167 has an output discharge function that provides a resistive discharge path for the external output capacitor. The function is active when the part is disabled (input voltage is under UVLO or EN is off), and the discharge path turns off when VOUT < 50mV or the 50ms maximum timer is reached. Thermal Shutdown (TSD) Thermal shutdown prevents the part from operating at exceedingly high temperatures. When the silicon die temperature exceeds 150°C, the entire chip shuts down. When the temperature falls below its lower threshold (typically 130°C), the chip is enabled. This is a non-latch protection. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 15 MP28167 – 22V VIN, 3A IOUT INTEGRATED BUCK-BOOST CONVERTER APPLICATION INFORMATION Component Selection The Over-Current Limit Set (RSET) The MP28167 current-limit value should be greater than the normal maximum load current, allowing the tolerances in the current-sense value. The current limit can be determined with Equation (1): RSET (k)= 75.24 I _ limit(A) (1) This also provides the theory result. Table 1 lists the recommended ILIM setting resistor and capacitor values, based on the EVB. Table 1: R_OC vs. I_LIMIT R_OC (kΩ) 75 64.9 54.9 44.2 37.4 30 21.5 15 C_OC (nF) 6.8 6.8 8.2 10 12 15 22 33 I_LIMIT (A) 0.98 1.15 1.37 1.72 2.04 2.54 3.56 5.11 Selecting the Inductor As one buck-boost topology circuit, the inductor must support buck applications with the maximum input voltage, and boost applications with the minimum input voltage. Two critical inductance values can be determined, according to the buck mode and boost mode current ripples, using Equation (2) and Equation (3): LMINBUCK  LMINBOOST  VOUT  (VIN(MAX)  VOUT ) VIN(MAX)  fREQ  IL VIN(MIN)  (VOUT  VIN(MIN) ) VOUT  fREQ  IL In addition to the inductance value, to avoid saturation, the inductor must support the peak current, based on Equation (4) and Equation (5): IPEAK BUCK  IOUT  IPEAK BOOST  VOUT  (VIN(MAX)  VOUT ) 2  VIN(MAX)  fREQ  L (4) VOUT  IOUT VIN(MIN)  (VOUT  VIN(MIN) ) (5)   VIN(MIN) 2  VOUT  fREQ  L Where η is the estimated efficiency of the MP28167. Input and Output Capacitor Selection It is recommended to use ceramic capacitors plus electrolytic capacitors for the input and output capacitors, in order to filter input and output ripple current and obtain stable operation. The input capacitor requires enough capacitance to absorb the input switching current. For most applications, a 100µF electrolytic capacitor plus a 22µF ceramic capacitor is sufficient. The output capacitor stabilizes the DC output voltage. Low-ESR capacitors with enough capacitance to limit the output voltage ripple are preferred. Refer to application schematic for more detail. (2) (3) Where fREQ is the switching frequency and ∆IL is the peak-to-peak inductor current ripple. As a rule of thumb, the peak-to-peak ripple can be set at 10% to 40% of the inductor current. The minimum inductor value for the application must be higher than both the Equation (2) and Equation (3) results. MP28167 Rev 1.0 4/29/2019 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 16 MP28167 – 22V VIN, 3A IOUT INTEGRATED BUCK-BOOST CONVERTER PCB Layout Guidelines (9) Efficient PCB layout is critical for successful operation and thermal dissipation. For best results, refer to Figure 8 and the guidelines below: 1. Place the ceramic CIN and COUT capacitors close to the IC’s VIN-to-GND and OUT-toGND pins, respectively. 2. Use a large copper plane for PGND. Add multiple vias to improve thermal dissipation. Connect AGND to PGND. 3. Use short, direct, and wide traces to connect OUT. Adding vias under the IC and then routing the OUT trace on both PCB layers is highly recommended. 4. Place a large copper plane for SW1, SW2. 5. Place the VCC decoupling capacitor as close to VCC as possible. Top Layer Note: 9) The recommended layout is based on the Typical Application Circuit on page 18. Zoom View of IC Figure 8: Recommended Layout MP28167 Rev 1.0 4/29/2019 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 17 MP28167 – 22V VIN, 3A IOUT INTEGRATED BUCK-BOOST CONVERTER TYPICAL APPLICATION CIRCUITS C4 16 VIN 2.8V–22V C1 100µF + 100nF 1 C1B 22µF C1A 0.1µF SW1 BST1 IN BST2 R3 499k 3 SW2 OUT 13 C5 100nF 14 VOUT 5V C2A 0.1µF MP28167 C2B 10µF C2C 10µF C2 100µF E MZJ350A RA 101MHA NC NC RSV1 RSV2 OC VCC C3 1µF AGND 10 4.7µH 12 EN C7 22nF 9 L1 15 GND 2, 11 4 8 5 6 7 C6 22nF R2 21.5k Figure 9: Typical Application Circuit for 2.8V-22VIN, 5VOUT, 3A Output Current or 4A Input Current C4 16 VIN 2.8V–22V C1 100µF + 100nF 1 C1B 22µF C1A 0.1µF BST1 SW1 IN BST2 R3 499k 3 SW2 OUT 13 C5 VCC AGND 10 GND 2, 11 R2 21.5k 100nF 14 VOUT 5V C2A 0.1µF MP28167 C3 1µF 4.7µH 12 EN C7 22nF 9 L1 15 NC NC RSV1 RSV2 OC C2B 22µF C2C 22µF C2 22µF C2C 22µF C2 22µF 4 8 5 6 7 C6 22nF Figure 10: Typical Application Circuit for 2.8V-22VIN, 5VOUT, 3A Output Current or 4A Input Current MP28167 Rev 1.0 4/29/2019 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 18 MP28167 – 22V VIN, 3A IOUT INTEGRATED BUCK-BOOST CONVERTER PACKAGE INFORMATION QFN-16 (3mmx3mm) NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that thirdparty Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not assume any legal responsibility for any said applications. MP28167 Rev 1.0 4/29/2019 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2019 MPS. All Rights Reserved. 19