MP26085DJ-LF-Z

HF900 900V Offline Switching Regulator The Future of Analog IC Technology DESCRIPTION FEATURES The HF900 is a flyback regulator with an integrated 900V MOSFET. Requiring a minimum number of external components, the HF900 provides excellent power regulation in AC/DC applications that require high reliability. These applications include smart meters, large appliances, industrial controls, and products powered by unstable AC grids. • • The regulator uses peak-current-mode control to provide excellent transient response and easy loop compensation. When the output power falls below a given level, the regulator enters burst mode to lower the standby power consumption. The MPS proprietary 900V monolithic process enables over-temperature protection (OTP) on the same silicon of the 900V power FET, offering precise thermal protection. Also, it offers a full suite of protection features such as VCC undervoltage lockout, over-load protection, overvoltage protection, and short-circuit protection. The HF900 is designed to minimize electromagnetic interference for wireless communication in home and building automation applications. The operating frequency is programmed externally with a single resistor, so the power supply’s radiated energy can be designed to avoid the interference with wireless communication. In addition to the programmable frequency, the HF900 employs a frequency jittering function that not only greatly reduces the noise level but also reduces the cost of the EMI filter. • • • • • • • • • • • • • Internal Integrated 900V MOSFET Programmable Fixed Switching Frequency up to 300kHz Frequency Jittering Current-Mode Operation Internal High-Voltage Current Source Low Standby Power Consumption via Active Burst Mode Internal Leading Edge Blanking Built-In Soft-Start Function Internal Slope Compensation Built-In Input Over-Voltage Protection Over-Temperature Protection (OTP) VCC Under-Voltage Lockout with Hysteresis Over-Voltage Protection on VCC Time-Based Overload Protection Short-Circuit Protection (SCP) APPLICATIONS • • • • Smart Power Meters Large Appliances Industrial Controls All AC/DC Supplies Sold Where Power Grid may be Unstable All MPS parts are lead-free, halogen free, and adhere to the RoHS directive. For MPS green status, please visit MPS website under Quality Assurance. “MPS” and “The Future of Analog IC Technology” are Registered Trademarks of Monolithic Power Systems, Inc. The HF900 is available in SOIC14-11 and PDIP8-7EP packages. HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 1 HF900 – 900V OFFLINE SWITCHING REGULATOR TYPICAL APPLICATION HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 2 HF900 – 900V OFFLINE SWITCHING REGULATOR ORDERING INFORMATION Part Number* HF900GPR HF900GS Package PDIP8-7EP SOIC14-11 Top Marking See Below See Below * For Tape & Reel, add suffix –Z (e.g. HF900GPR–Z); TOP MARKING (PDIP8-7EP) HF900: part number; MPS: MPS prefix: YY: year code; WW: week code: LLLLLLLL: lot number; TOP MARKING (SOIC14-11) MPS: MPS prefix: YY: year code; WW: week code: HF900: part number; LLLLLLLLL: lot number; HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 3 HF900 – 900V OFFLINE SWITCHING REGULATOR PACKAGE REFERENCE TOP VIEW TOP VIEW PDIP8-7EP SOIC14-11 ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance DRAIN..........................................–0.3V to 900V VCC ...............................................–0.3V to 30V All other pins .................................–0.3V to 6.5V (2) Continuous power dissipation (TA = +25°C) PDIP8-7EP .............................................. 1.47W SOIC14-11 ............................................... 1.45W Junction temperature ................................150°C Lead temperature .....................................260°C Storage temperature ................ -60°C to +150°C ESD capability human body model .......... 2.0kV ESD capability charged device model ...... 2.0kV PDIP8-7EP..............................68 ....... 7 .... °C/W SOIC14-11 ..............................70 ...... 35 ... °C/W Recommended Operation Conditions (3) (4) θJA θJC NOTES: 1) Exceeding these ratings may damage the device. 2) The maximum allowable power dissipation is a function of the maximum junction temperature TJ (MAX), the junction-toambient thermal resistance θJA, and the ambient temperature TA. The maximum allowable continuous power dissipation at any ambient temperature is calculated by PD (MAX) = (TJ (MAX)-TA)/θJA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage. 3) The device is not guaranteed to function outside of its operating conditions. 4) Measured on JESD51-7, 4-layer PCB. VCC to GND .............................10.1 V to 24.5 V Operating junction temp (TJ) .. -40 °C to +125 °C HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 4 HF900 – 900V OFFLINE SWITCHING REGULATOR ELECTRICAL CHARACTERISTICS VCC =12V, TJ=-40°C~125°C, Min & Max are guaranteed by characterization, typical is tested under 25°C, unless otherwise noted. Parameter Symbol Conditions Min Typ Max Unit 2 3.1 mA 15 30 μA Start-Up Current Source (DRAIN) Supply current from DRAIN Leakage current from DRAIN ICharge VCC = 6V; VDrain = 400V ILeak VCC = 13V; VDrain = 400V Breakdown voltage V(BR)DSS Ileakage = 100μA On-state resistance RDS(ON) VCC = 10.1V; IDrain = 100mA 1.35 900 V TJ = 25°C 13 17 Ω TJ = 125°C 22 26 Ω Supply Voltage Management (VCC) VCC upper level where the IC switches on VCCH 11.5 13.0 14.5 V VCC lower level where the IC switches off VCCL 8.9 9.4 10.1 V VCC hysteresis VCC_HYS 2.7 3.6 4.6 V VCC OVP level VOVP 24.5 26.0 27.3 V VCC re-charge level where the protection occurs VCCR 4.5 5.3 6 V 700 μA Quiescent current at protection phase IPro VCC = 6V Quiescent current IQ VCC = 13V 780 980 µA Operation current ICC VCC = 13V; fS = 100kHz 1.7 2 mA Feedback Management (FB) Internal pull-up resistor RFB Internal pull-up voltage VUP FB to current-set-point division ratio Internal soft-start time 10 3.8 kΩ 4.1 4.4 Idiv 3.3 3.6 TSS 3 V ms FB decreasing level where the regulator enters burst mode VBURL 0.4 0.5 0.6 V FB increasing level where the regulator leaves burst mode VBURH 0.58 0.70 0.86 V Overload set point VOLP 3.5 3.8 4.1 V Overload delay time TDelay fS = 100kHz 82 ms Timing Resistor (FSET) FSET reference voltage Frequency spectrum jittering range in percentage of Fs Typical operating frequency HF900 Rev. 1.0 8/4/2015 VFSET RJittering fS 1.15 Example: fS = 100kHz, then jittering is ±4kHz TJ = 25°C; RFSET = 100kΩ 1.23 1.3 ±4 90 104 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. V % 118 kHz 5 HF900 – 900V OFFLINE SWITCHING REGULATOR ELECTRICAL CHARACTERISTICS VCC =12V, TJ=-40°C~125°C, Min & Max are guaranteed by characterization, typical is tested under 25°C, unless otherwise noted. Parameter Symbol Conditions Min Typ Max Unit Current Sampling Management (SOURCE) Leading edge blanking for current sensor TLEB1 350 ns Leading edge blanking for SCP TLEB2 300 ns Maximum current set point VCS 0.90 0.97 1.04 V Short-circuit point VSC 1.32 1.42 1.62 V protection set Slope compensation ramp SRamp fS = 100kHz 40 mV/μs Protection Management (PRO) Protection voltage VPRO Protection hysteresis VHY 2.92 3.1 3.32 V 0.2 V 150 °C 30 °C Thermal Shutdown Thermal threshold(5) shutdown Thermal shutdown recovery hysteresis(5) Notes: 5) Guaranteed by Design & Characterization. HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 6 HF900 – 900V OFFLINE SWITCHING REGULATOR TYPICAL CHARACTERISTICS VCC Low Level vs. Temperature 26.1 13.4 9.5 26.0 12.8 12.6 0 50 100 9.3 9.2 9.1 9.0 -50 150 6.3 6.1 5.9 5.7 5.5 5.3 5.1 4.9 4.7 4.5 4.3 -50 0 50 100 150 0.74 0.72 0.7 0.68 0.66 0.64 0.62 0.6 -50 HF900 Rev. 1.0 8/4/2015 0 50 100 150 25.8 25.7 25.6 25.5 -50 150 3.5 3.4 3.3 3.2 3.1 3 2.9 -50 0 50 100 150 3.9 3.85 3.8 3.75 3.7 3.65 3.6 0 50 100 50 100 150 0.6 0.55 0.5 0.45 0.4 -50 150 0 50 100 150 Over Load Delay Time vs. Temperature 85 4 3.95 3.55 3.5 -50 0 FB Level Enter Burst Mode vs. Temperature Over Load Set Point vs. Temperature OVER LOAD SET POINT (V) 0.76 100 3.6 FB Level Leave Burst Mode vs. Temperature 0.8 0.78 50 25.9 FB to Current Division Ratio vs. Temperature FB TO CURRENT DIVISION RATIO VCC RE-CHARGE LEVEL (V) VCC Re-Charge Level vs. Temperature 0 FB LEVEL ENTER BURST MODE (V) 13.0 9.4 OVER LOAD DELAY TIME (ms) 13.2 VCC UPPER LEVEL (V) 9.6 12.4 -50 FB LEVEL LEAVE BURST MODE (V) VCC OVP Threshold Voltage vs. Temperature 13.6 VCC LOW LEVEL (V) VCC UPPER LEVEL (V) VCC Upper Level vs. Temperature Fs=100kHz 84.5 84 83.5 83 82.5 82 81.5 81 80.5 80 -50 0 50 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 100 150 7 HF900 – 900V OFFLINE SWITCHING REGULATOR TYPICAL CHARACTERISTICS (continued) 1. 26 1. 24 1. 22 1. 2 1. 18 1. 16 1. 14 1. 12 1. 1 -50 0 50 100 150 1. 06 1. 04 1. 02 1 0. 98 0. 96 0. 94 0. 92 0. 9 -50 2.0 3. 25 1.8 3. 2 1.6 3. 15 1.4 3. 1 1.2 3. 05 1.0 3 0.8 2. 95 0.6 50 100 0.4 -50 150 50 100 150 1. 55 1. 5 1. 45 1. 4 -50 0 50 100 150 1150 1100 1050 1000 950 0 50 100 150 900 -50 -25 0 25 50 75 100 125 150 Typical Operating Frequency vs. Junction Temperature 225 200 175 150 125 100 75 50 25 0 -50 -25 HF900 Rev. 1.0 8/4/2015 0 25 50 75 100 125 OPERATING FREQUENCY FS (kHz) PRO PROTECTION VOLTAGE (V) TYPICAL OPERATING FREQUENCY FS (kHz) 3. 3 0 0 1. 6 R_ON@VCC=10.1V vs. Temperature Pro Protection Voltage vs. Temperature 2. 9 -50 Short Circuit Protection Set Point vs. Temperature SHORT CIRCUIT PROTECTION SET POINT (V) 1. 3 1. 28 Max Current Set Point vs. Temperature MAX CURRENT SET POINT (V) FSET REFERENCE VOLTAGE (V) Fset Reference Voltage vs. Temperature 225 200 175 150 125 100 75 50 25 0 25 50 75 100 125 150 175 200 225 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 8 HF900 – 900V OFFLINE SWITCHING REGULATOR TYPICAL PERFORMANCE CHARACTERISTICS Performance waveforms are tested on the evaluation board of the Design Example section. VIN = 230V, VOUT1 = 12.5V, VOUT2 = 5V, Primary Inductance=2.5mH, NP:NAUX:NS1:NS2 = 125:14:14:9, TA = 25°C, unless otherwise noted. Efficiency 100 80 60 40 20 0 0 0.2 0.4 0.6 0.8 1 1.2 VBUS 100V/div. VBUS 100V/div. VBUS 100V/div. VOUT1 5V/div. VOUT1 5V/div. VOUT1 5V/div. VOUT2 2V/div. VOUT2 2V/div. VOUT2 2V/div. VSW 100V/div. VSW 100V/div. VCC 10V/div. VFB 2V/div. VCC 10V/div. VFB 2V/div. VBUS 100V/div. VOUT1 5V/div. VOUT2 2V/div. HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 9 HF900 – 900V OFFLINE SWITCHING REGULATOR TYPICAL PERFORMANCE CHARACTERISTICS (continued) Performance waveforms are tested on the evaluation board of the Design Example section. VIN = 230V, VOUT1 = 12.5V, VOUT2 = 5V, Primary Inductance=2.5mH, NP:NAUX:NS1:NS2 = 125:14:14:9, TA = 25°C, unless otherwise noted. VSW 100V/div. VSW 100V/div. VSW 100V/div. VCC 10V/div. VFB 2V/div. VCC 10V/div. VCC 10V/div. VOUT1 100mV/div. VOUT1 50mV/div. VOUT2 20mV/div. VOUT2 20mV/div. VSW 100V/div. VCC 10V/div. VFB 2V/div. VDS 200V/div. VDS 200V/div. VPRO 1V/div. HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 10 HF900 – 900V OFFLINE SWITCHING REGULATOR PIN FUNCTIONS Pin # Pin # PDIP8-7EP SOIC14-11 Name 1 6 FB 2 5 PRO 3 4 FSET 4 3 VCC 5 14 DRAIN 7 9 SOURCE 8 1,2,7,8 13 GND NC HF900 Rev. 1.0 8/4/2015 Description Feedback. The output voltage from the external compensation circuit is fed into this pin. FB and the current sense signal from SOURCE determines the PWM duty cycle. A feedback voltage of VOLP triggers overload protection while VBURL triggers burst-mode operation. The regulator exits burst-mode operation and enters normal operation when the FB voltage reaches VBURH. Input over-voltage protection. When voltage on PRO rises to VPRO, the IC is shut down with hysteresis. Switching converter frequency set. Connect a resistor to GND to set the switching frequency up to 300kHz. Supply voltage. Connect a 22μF bulk capacitor and a 0.1µF ceramic capacitor for most applications. When VCC rises to VCCH, the IC starts switching; when it falls below VCCL, the IC stops switching. Drain of the internal MOSFET. Input for the start-up high-voltage current source. Source of the internal MOSFET. Input of the primary current sense signal. IC ground. Not connected. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 11 HF900 – 900V OFFLINE SWITCHING REGULATOR FUNCTIONAL BLOCK DIAGRAM Power Management OVP Frequency Control Driving-Signal Management OTP OLP Fault-Signal Management SCP Burst-Mode Control Peak Current Conversion Current-Sensor Comparator LEB1 SCP Comparator LEB2 Figure 1: Internal Function Block Diagram HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 12 HF900 – 900V OFFLINE SWITCHING REGULATOR OPERATION The HF900 integrates a 900V MOSFET for a reliable switch-mode power supply solution. It has burst-mode operation to minimize the standby power consumption at light load. Protection features such as auto-recovery for overload protection (OLP), short-circuit protection (SCP), over-voltage protection (OVP), and thermal shutdown for over-temperature protection (OTP) contribute to a safer converter design with minimal external components. PWM Operation The HF900 employs peak-current-mode control. On the secondary side, the output voltage is divided by a voltage divider network. This voltage is fed back to the primary side as voltage on the FB using an optocoupler and a shunt regulator. The voltage at FB is compared to the VSense voltage, which measures the MOSFET switching current. The integrated MOSFET turns on at the beginning of each clock cycle. The current in the transformer magnetizing inductance increases until it reaches the value set by the FB voltage, and then the integrated MOSFET turns off. The lower threshold of VCC UVLO decreases from VCCL to VCCR when fault conditions such as SCP, OLP, OVP, and OTP occur. Soft Start The HF900 implements an internal soft-start circuit to reduce stress on the primary-side MOSFET and the secondary diode and smoothly establish the output voltage during start-up. The internal soft-start circuit increases the primary current sense threshold gradually, which determines the MOSFET peak current during start-up. The pulse width of the power switching device is increased progressively to establish correct operating conditions until the feedback control loop takes charge (see Figure 3). Start-Up and VCC UVLO Initially, the IC is driven by the internal current source, which is drawn from the high-voltage DRAIN. The IC starts switching, and the internal high-voltage current source turns off as soon as the voltage on VCC reaches VCCH. At this point, the supply of the IC is taken over by the auxiliary winding of the transformer. When VCC falls below VCCL, the regulator stops switching, and the internal high-voltage current source turns on again (see Figure 2). VCC Auxiliary Winding Takes Charge Figure 3: Soft Start Switching Frequency The switching frequency of the HF900 can be set by FSET. The frequency can be set by a resistor between FSET and GND. The oscillator frequency can be attained using Equation (1): 1 Hz (1) fS = 200 × 10 −9 + 112.5 × 10 −12 × VCCH VCCL RFSET VFST VFST (1.23V) is the FSET pin reference voltage. Driver Switching Pluses Over-Voltage Protection (OVP) Monitoring the VCC voltage via a 20µs time constant filter allows the HF900 to enter OVP during an over-voltage condition, typically when VCC goes above VOVP. The regulator will resume operation once the fault disappears. Figure 2: VCC Start-Up HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 13 HF900 – 900V OFFLINE SWITCHING REGULATOR Overload Protection (OLP) The HF900 shuts down when the power supply experiences an overload. OLP is achieved by monitoring the FB voltage continuously. A fault signal is triggered when FB pulls up to 3.8V (VOLP, typical value) and after an 82ms delay (8192 switching cycle, fS = 100kHz). If the fault signal is still present, the HF900 shuts down. When the fault disappears, the power supply resumes operation. The OLP delay time can be attained using Equation (2): TDelay = 82ms × 100kHz fS VFB 0.7V 0.5V VDS (2) Short-Circuit Protection (SCP) The HF900 shuts down when voltage on CS is higher than VSC, which indicates a short circuit. The HF900 enters a safe low-power mode that prevents any thermal or stress damage. As soon as the fault disappears, the power supply resumes operation. Thermal Shutdown (OTP) When the junction temperature of the IC exceeds 150℃, the over-temperature protection is activated and stops output driver switching to prevent the HF900 from any thermal damage. As soon as the junction temperature drops below 120℃, the regulator resumes operation. During the protection period, the regulator enters autorecovery mode. The VCC voltage is discharged to VCCR and is re-charged to VCCH by the internal high-voltage current source. Burst Operation To minimize standby power consumption, the HF900 implements burst mode at no load and light load. As the load decreases, the FB voltage decreases. The IC stops switching when the FB voltage drops below 0.5V (VBRUL, typical value). As the load power increases, the output voltage drops at a rate dependent on the load. This causes the FB voltage to rise again due to the negative feedback control loop. Once the FB voltage exceeds 0.7V (VBRUH, typical value), the switching pulse resumes. The FB voltage then decreases, and the whole process repeats. Burst-mode operation alternately enables and disables the switching pulse of the MOSFET. Hence switching loss at no load and light load conditions is reduced greatly. HF900 Rev. 1.0 8/4/2015 Figure 4 shows the burst-mode operation of the HF900. Figure 4: Burst-Mode Operation PRO PRO provides extra protection against abnormal conditions. Use PRO for input OVP or other protections (input UVP, over-temperature protection for key components, etc.). If the PRO voltage exceeds 3.1V (VPRO, typical value), the IC shuts down to enter auto-recovery mode. Once the fault disappears, the power supply resumes operation. Peak Current Limit In normal operation, the primary peak current is sensed by a sensing resistor between SOURCE and GND. The turn-off threshold of the MOSFET is set by the FB voltage (VSense = VFB/Idiv). When the sensing resistor voltage reaches VSense, the MOSFET turns off. The Idiv is the FB to the current-set-point division ratio. During an overload condition, the primary peak current threshold is limited internally to the maximum value of 0.97V (VCS, typical value), even if the VFB voltage exceeds 3.2V, to avoid excessive output power and lower the switch voltage rating. During the start-up period, the primary peak current threshold increases internally to the maximum current set point (VCS) gradually. Leading Edge Blanking (LEB) In order to avoid turning off the MOSFET by mistrigger spikes shortly after the switch turns www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 14 HF900 – 900V OFFLINE SWITCHING REGULATOR on, the IC implements leading edge blanking. During the blanking time, any trigger signal on SOURCE is blocked. An internal leading edge blanking (LEB) unit containing two LEB times is employed between SOURCE and the current comparator input to avoid premature switching pulse termination due to the parasitic capacitances. During the blanking time, the current comparator is disabled and cannot turn off the MOSFET. Current sensor leading edge blanking inhibits the current limitation comparator for 350ns (TLEB1, typical value), and the SCP leading edge blanking inhibits the SCP current comparator for 300ns (TLEB2, typical value). Figure 5 shows the primary current sense waveform and the leading edge blanking. Figure 5: Leading Edge Blanking HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 15 HF900 – 900V OFFLINE SWITCHING REGULATOR APPLICATION INFORMATION Selecting the Input Capacitor The bulk capacitors of the rectifier bridge filter the rectified AC input, which supplies the DC input voltage for the converter. Figure 6 shows the typical DC bus voltage waveform of a full-bridge rectifier. Vin As a 900V offline regulator, the HF900 suits very high-voltage input applications. General input capacitors with 400V voltage ratings cannot satisfy the safety requirement. Thus, stack capacitors can be used in very high input voltage applications such as a 420VAC input (see Figure 7). Bus voltage VDC(max) DC input voltage R1 D1 VDC(min) VAC 85~420VAC t D3 Figure 6: Input Voltage Waveform VO × IO η (3) Where VO is the output voltage, IO is the rated output current, and η is the estimated efficiency. Generally, η is between 0.75 and 0.85 depending on the input range and output application. From the waveform in Figure 6, the AC input voltage (VAC) and the DC input voltage (VDC) are calculated using Equation (4): VDC (VAC ,t) = 2 × VAC 2 − 2 × Pin ×t Cin (4) VAC starts to charge the input capacitor when the DC bus voltage reaches the minimum value (VDC = VAC, approximately). t1 can be calculated using Equation (5): VDC(min) = VDC (VAC(min) ,t1) (5) Very low DC input voltage can cause a thermal problem in a full load. It is recommended that the minimum DC voltage is higher than 70V. Otherwise the input capacitor value should be increased. HF900 Rev. 1.0 8/4/2015 D4 R3 C2 When the full-bridge rectifier is used, usually the input capacitor is set at 2μF/W for the universal input condition (85~265VAC). For high-voltage input (>185VAC) application, cut the capacitor values in half. The input power (Pin) is estimated with Equation (3): Pin = C1 R2 AC input voltage t1 0 D2 R4 Figure 7: Input Stack Capacitor Circuit C1 and C2 endure half of the input DC voltage rating, respectively. R1 to R4 should use the same value resistor to equalize the C1 and C2 voltage stress. It is recommended to use a 1206 package for R1 to R4 to satisfy the safety requirement. Also, the R1 to R4 values should be large enough for energy saving. For example, the total value of R1 to R4 is 20MΩ, which consumes about 18mW in 600VDC bus voltage. Primary-Side Inductor Design (Lm) Normally, the converter is designed to operate in CCM with low input voltage. CCM is needed to satisfy the output energy requirement for the universal input condition. With a built-in slope compensation function, the HF900 supports CCM when the duty cycle exceeds 50%. Set the ratio (KP) of the primary inductor ripple current amplitude vs. the peak current value to 0 < KP ≤ 1, where KP = 1 for DCM. Figure 8 shows the relevant waveforms. A larger inductor leads to a smaller KP, which reduces RMS current but increases the transformer size. For 5W application, an optimal KP value is between 0.8 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 16 HF900 – 900V OFFLINE SWITCHING REGULATOR and 1 for the universal input range and 1 for a 230VAC input range. Current-Sense Resistor SRamp×TON Ipeak×Rsense TON Figure 8: Typical Primary Current Waveform Figure 9: Slope Compensation Waveform For CCM at a minimum input, the converter duty cycle is determined using Equation (6): (VO + VF ) × N (6) D= (VO + VF ) × N + VDC(min) Figure 9 shows the slope compensation waveform. When the sum of the sense resistor voltage and the slope compensation voltage reaches the peak current limit (VCS), the HF900 turns off the internal MOSFET. The maximum peak current limit is 0.97V (VCS, typical value), and the slope compensation slew rate is 40mV/µs. Considering the margin, use 0.95×VCS as the peak current limit at full load. The voltage on the sense resistor is given using Equation (13): (13) Vsense = 0.95 × VCS − SRamp × TON Where: VF is the secondary diode’s forward voltage, and N is the transformer turns ratio. The MOSFET turn-on time is calculated with Equation (7): TON = D fS (7) Where, fS is the operating frequency. The input average current, ripple current, peak current, and valley current of the primary side are calculated using Equation (8), Equation (9), Equation (10) and Equation (11): Pin (8) I = AV VDC(min) Iripple = K P × Ipeak (9) IAV = K (1 − P ) × D 2 (10) Ivalley = (1 − K P ) × Ipeak (11) Ipeak The value of the sense resistor is calculated using Equation (14): V (14) Rsense = sense Ipeak Use Equation (15) to select the current sense resistor with an appropriate power rating based on the power loss: 2 ⎡⎛ I + I 2⎤ ⎞ 1 Psense = ⎢⎜ peak valley ⎟ + × (Ipeak − Ivalley ) ⎥ × D × Rsense (15) 2 ⎢⎣⎝ ⎥⎦ ⎠ 12 PRO Extra protection can be enabled using the HF900 PRO. A typical input over-voltage protection circuitry is shown in Figure 10. Estimate Lm using Equation (12): Lm = HF900 Rev. 1.0 8/4/2015 VDC(min) × TON Iripple (12) www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 17 HF900 – 900V OFFLINE SWITCHING REGULATOR Figure 10: Input Over-Voltage Protection Setup The input over-voltage protection point can be calculated using Equation (16): VINOVP = VPRO × R5 + R6 + R7 + R8 R8 (16) For resistors R5 to R7, 1206 packages should be used for safety considerations. The total value should be larger than 10MΩ for energy saving purposes. Switching voltage noise can occur if R% to R* have large values, which disturbs the PRO protection action. One ceramic capacitor (around 1nF) should be paralleled with PRO and GND. It should be located near the IC to decouple the switching voltage noise. Frequency Jittering The HF900 provides a frequency jittering function, which simplifies the input EMI filter design and decreases the system cost. The HF900 has optimized frequency jittering with a ±4% frequency deviation range and a 256TS carrier cycle that effectively improves EMI by spreading the energy dissipation over the frequency range. Thermal Performance Optimization The HF900 is dedicated to high input voltage application. However, the high input voltage can cause greater switching loss on the MOSFET, especially under a high frequency, which may lead to poor thermal performance. Tests show that turn-on loss is dominant under a high input, so thermal performance optimization should focus mainly on reducing turn-on loss. As we know that turn-on loss is caused by a turnon current spike and VDS, measures should be HF900 Rev. 1.0 8/4/2015 taken to reduce either the VDS or the turn-on spike to get better thermal performance. In order to reduce VDS, use a small turns ratio-N to minimize the reflected output voltage on the primary MOSFET. To suppress a turn-on spike of the MOSFET, CCM operation should be avoided, especially under a high input. The transformer structure should be designed to achieve minimum parasitic capacitance of each winding and between the primary and secondary windings. For the HF900 PDIP8-7EP package, a heat sink can be used to further improve thermal performance in very critical applications. In addition, choose an appropriate operating frequency for better thermal performance and EMI. Table 1 shows the maximum output power test results of the HF900 (both packages were tested without a heat sink). Table 1: Maximum Output Power Package PDIP8-7EP SOIC14-11 fs (kHz) 50 100 50 100 PMAX (W) 7 3 8 4 NOTES: 1. The maximum output power is tested under TA = 50°C. 2. In order to reduce VDS, the turns ratio is set to 5. 3. VIN = 85~420VAC, single output, VOUT = 12.5V. 4. PDIP8-7EP package is tested without a heat sink, and GND is 2 connected to 2cm copper areas. GND of the SOIC14-11 package 2 is connected to 2.5cm copper areas. 5. Working condition under VIN = 85VAC is set to BCM. PCB Layout Guidelines Efficient PCB layout is critical to achieve reliable operation, good EMI performance, and good thermal performance. For best results, refer to Figure 11 and follow the guidelines below: 1) Minimize the power stage switching stage loop area. This includes the input loop (C2– C1-T1–U1–R12/R13–C2), the auxiliary winding loop (T1–D6–C6–T1), the output loop (T1–D8–C9–T1 and T1–D7–C7–T1), and the RCD loop (T1–D5–R16/R17/C3–T1). 2) Keep the input loop, GND, and control circuit separate and only connect them at C2. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 18 HF900 – 900V OFFLINE SWITCHING REGULATOR 3) Connect the heat sink to the primary GND plane to improve EMI and thermal dissipation. 4) Place the control circuit capacitors (for FB, PRO, and VCC) close to the IC to decouple the switching voltage noise. 5) Enlarge the GND pad near the IC for good thermal dissipation. 6) Keep the EMI filter far away from the switching point. 7) Ensure the two outputs clearance distance satisfy the insulation requirement. Input Loop Output2 Loop Output1 Loop Design Example Table 2 is a design example using the application guidelines for the given specifications: Table 2: Design Example VIN 85 to 420VAC VOUT1 12.5V IOUT1 0.4A VOUT2 5V IOUT2 0.05A fS 100kHz The detailed application schematic is shown in Figure 12. The typical performance and circuit waveforms have been shown in the typical performance characteristics section. For more device applications, please refer to the related evaluation board datasheets. Auxiliary Winding Loop a) Top b) Bottom Figure 11: Recommended PCB Layout HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 19 HF900 – 900V OFFLINE SWITCHING REGULATOR TYPICAL APPLICATION CIRCUITS R1 D1 2.2M/1206 CX1 D2 1N4007 0.22uF/275V 1N4007 C1 22uF/400V LX1 R2 R8 5.1M /1206 R16 R17 499k/1206 499k/1206 N5 1 C3 7448640416 /18mH CX2 C2 22uF/400V 2 R3 D3 2.2M/1206 D5 S1ML/1kV/1A 1N4007 N4 N3 R18 C11 10/1206 1nF /250V/0805 D8 MBRS3200/200V/3A 6 4 C8 1uF /50V GND VOUT1 C9 1000uF /25V C10 1uF /50V GND(L) CY1 D4 1N4007 5 3 R10 5.1M /1206 C7 22uF/50V B1100/100V/1A 9 N2 2.2nF/630V/1206 2.2M/1206 0.22uF/275V 10 N1 R9 5.1M /1206 U3 D7 VOUT2 NC 10/1W L L T1 Primary inductance: 2.5mH N1:N2:N3:N4:N5=18:125:14:14:9 FR1 R11 5.1M /1206 R19 1k 1nF R22 40.2k/1% D6 BAV21W/200V/0.2A U2 R4 10M/1206 R15 2.49/0805 HF900 R20 2k U1 MP110 Drain R5 1M/1206 VCC EL817B FSET R6 1M/1206 Pro R7 51k/0805 Source Pro R13 5.1/1% /1206 R12 5.1/1%/1206 GND Pro FB C6 22uF/50V C5 0.1uF R14 100k/1% R21 C12 20k 100nF U4 C4 1nF TL431K/2.5V R23 10k/1% C13 1nF Figure 12: Typical Application Schematic 3mm wall Primary Secondary 3T NC N1 10 N5 N5 3T 9 N2 3mm wall N4 1 1T N3 2 1T N3 3 4 N2 5 N4 6 1T N1 1T a) Connection Diagram b) Winding Diagram Figure 13: Transformer Structure HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 20 HF900 – 900V OFFLINE SWITCHING REGULATOR Table 3: Winding Order Tape (T) Winding Margin Wall PRI side Terminal Start—>End Margin Wall SEC side Wire Size (φ) Turns (T) N1 0mm 1→NC 0mm 0.18mm*2 18 N2 0mm 2→1 0mm 0.18mm*1 125 N3 0mm 4→3 0mm 0.15mm*1 14 N4 0mm 5→6 0mm 0.4mm*1 14 N5 3mm 10→9 3mm 0.2mm*1 9 1 1 1 1 3 3 HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 21 HF900 – 900V OFFLINE SWITCHING REGULATOR FLOW CHART HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 22 HF900 – 900V OFFLINE SWITCHING REGULATOR EVOLUTION OF THE SIGNALS IN PRESENCE OF FAULTS HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 23 HF900 – 900V OFFLINE SWITCHING REGULATOR PACKAGE INFORMATION PDIP8-7EP HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 24 HF900 – 900V OFFLINE SWITCHING REGULATOR SOIC14-11 0.338(8.55) 0.344(8.75) 0.024(0.61) 8 14 0.063 (1.60) 0.150 (3.80) 0.157 (4.00) PIN 1 ID 0.050(1.27) 0.228 (5.80) 0.244 (6.20) 0.213 (5.40) 7 1 TOP VIEW RECOMMENDED LAND PATTERN 0.053(1.35) 0.069(1.75) SEATING PLANE 0.050(1.27) BSC 0.013(0.33) 0.020(0.51) 0.004(0.10) 0.010(0.25) SEE DETAIL "A" SIDE VIEW FRONT VIEW 0.010(0.25) x 45o 0.020(0.50) GAUGE PLANE 0.010(0.25) BSC 0o-8o 0.016(0.41) 0.050(1.27) 0.0075(0.19) 0.0098(0.25) NOTE: 1) CONTROL DIMENSION IS IN INCHES. DIMENSION IN BRACKET IS IN MILLIMETERS. 2) PACKAGE LENGTH DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. 3) PACKAGE WIDTH DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. 4) LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.004" INCHES MAX. 5) DRAWING CONFORMS TO JEDEC MS-012, VARIATION AB. 6) DRAWING IS NOT TO SCALE. DETAIL "A" NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that third party 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. HF900 Rev. 1.0 8/4/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 25