FAN7528MX

FAN7528 Dual-Output, Critical Conduction Mode PFC Controller February 2007 FAN7528 Dual-Output, Critical Conduction Mode PFC Controller Features Low Total Harmonic Distortion (THD) Dual Output Voltage Control Precise Adjustable Output Over-Voltage Protection Open-Feedback Protection and Disable Function Zero Current Detector 160µs Internal Start-up Timer MOSFET Over-Current Protection Under-Voltage Lockout with 3.5V Hysteresis Low Start-up (40µA) and Operating Current (1.5mA) Totem-Pole Output with High State Clamp ±400mA Peak Gate Drive Current 8-Pin DIP or 8-Pin SOP Description The FAN7528 is an active power factor correction (PFC) controller for boost PFC applications that operates in critical conduction mode (CRM). It uses voltage mode PWM that compares an internal ramp signal with the error amplifier output to generate MOSFET turn-off signal. Because the voltage mode CRM PFC controller does not need the rectified AC line voltage information, it can save the power loss of the input voltage sensing network necessary for the current mode CRM PFC controller. The FAN7528 provides the dual-output voltage control function without the AC line voltage sensing for adapter applications. It changes the PFC output voltage according to the AC line voltage. It provides protection functions such as over-voltage protection, open-feedback protection, over-current protection, and under-voltage lockout protection. The FAN7528 can be disabled if the INV pin voltage is lower than 0.45V and the operating current decreases to 65µA. Using a new variable on-time control method, THD is lower than the conventional CRM boost PFC ICs. Applications Adapter Related Application Notes AN-6012: Design of Power Factor Correction Circuit Using FAN7528 Ordering Information Part Number FAN7528N FAN7528M FAN7528MX Operating Temp. Range -40°C to +125°C -40°C to +125°C -40°C to +125°C Pb-Free Yes Yes Yes Package 8-DIP 8-SOP 8-SOP Packing Method Rail Rail Tape & Reel Marking Code FAN7528 FAN7528 FAN7528 © 2005 Fairchild Semiconductor Corporation FAN7528 Rev. 1.0.6 www.fairchildsemi.com FAN7528 Dual-Output, Critical Conduction Mode PFC Controller Typical Application Diagrams L AC IN VAUX R2 NAUX RZCD ZCD CO VCC MOT FAN7528 CS INV D VO COMP R1 GND FAN7528 Rev. 1.01 Figure 1. Typical Boost PFC Application Internal Block Diagram V CC 8 UVLO 2.5V Ref Internal Bias V ref Vcc 12V 8.5V Disable 160 μ s Timer S Drive Output 7 OUT 13V ZCD 5 6.7V 1.4V 1.5V Zero Current Detector Q R O VP 2.66V 2.55V CS 4 40k 8pF 0.8V Ramp Signal Disable OCP Comparator 0.45V 0.35V V CC =8.5V Reference Set V CC =4.5V Reference Reset 1V Offset MOT 3 Sawtooth Generator Error Amplifier Gm Dual-Output Reference Generator 1.5V/2.5V 1 INV 1V ~ 5V Range 6 2 GND COMP FAN7528 Rev. 1.00 Figure 2. Functional Block Diagram of FAN7528 © 2005 Fairchild Semiconductor Corporation FAN7528 Rev. 1.0.6 2 www.fairchildsemi.com FAN7528 Dual-Output, Critical Conduction Mode PFC Controller Pin Assignments VCC 8 OUT 7 GND 6 ZCD 5 WWW FAN7528 1 INV 2 COMP 3 MOT 4 CS FAN7528 Rev. 1.00 Figure 3. Pin Configuration (Top View) Pin Definitions Pin # 1 Name INV Description This pin is the inverting input of the error amplifier. The output voltage of the boost PFC converter should be resistively divided to 2.5V at the high line condition and connected to this pin. If this pin voltage is controlled to be lower than 0.45V, the device is disabled. This pin is the output of the transconductance error amplifier. Some components for the output voltage compensation should be connected between this pin and GND. This pin is used to set the slope of the internal ramp. The voltage of this pin is maintained to be 1V. If a resistor is connected between this pin and GND, current flows out of the pin and the slope of the internal ramp is proportional to this current. This pin is the input of the over-current protection comparator. The MOSFET current is sensed using a sensing resistor and the resulting voltage is applied to this pin. An internal RC filter is included to filter switching noise. This pin is sensitive to the negative voltage below -0.3V. For proper operation, the stray inductance in the sensing path and the inductance of the sensing resistor must be minimized. This pin is the input of the zero current detection block. If the voltage of this pin goes higher than 1.5V, then lower than 1.4V, the MOSFET is turned on. This pin is used for the ground potential of all the pins. For proper operation, the signal ground and the power ground should be separated. This pin is the gate drive output. The peak sourcing and sinking current level is 400mA. For proper operation, the stray inductance in the gate driving path must be minimized. This pin is the IC supply pin. IC current and MOSFET drive current are supplied using this pin. 2 3 COMP MOT 4 CS 5 6 7 8 ZCD GND OUT VCC © 2005 Fairchild Semiconductor Corporation FAN7528 Rev. 1.0.6 3 www.fairchildsemi.com FAN7528 Dual-Output, Critical Conduction Mode PFC Controller Absolute Maximum Ratings Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only. TA = 25°C unless otherwise specified. Symbol VCC IOH, IOL Iclamp Idet VIN TJ TA TSTG ESD Supply Voltage Parameter Peak Drive Output Current Driver Output Clamping Diodes VO > VCC or VO < -0.3V Detector Clamping Diodes Error Amp, MOT, CS Input Voltages Operating Junction Temperature Operating Temperature Range Storage Temperature Range Human Body Model Machine Model Value 23 ±400 ±10 ±10 -0.3 to 6 150 -40 to 125 -65 to 150 2.0 300 Unit V mA mA mA V °C °C °C kV V Thermal Impedance Symbol θJA Parameter Thermal Resistance, Junction-to-Ambient 8-DIP 8-SOP Value 110 150 Unit °C/W °C/W Note: 1. Regarding the test environment and PCB type, please refer to JESD51-2 and JESD51-10. © 2005 Fairchild Semiconductor Corporation FAN7528 Rev. 1.0.6 4 www.fairchildsemi.com FAN7528 Dual-Output, Critical Conduction Mode PFC Controller Electrical Characteristics VCC = 14V, TA = -40°C~125°C, unless otherwise specified. Symbol VTH(start) VTH(stop) HY(uvlo) IST ICC IDCC ICC(dis) Parameter Start Threshold Voltage Stop Threshold Voltage UVLO Hysteresis Start-up Supply Current Operating Supply Current Dynamic Operating Supply Current Operating Current at Disable Condition VCC increasing VCC decreasing Min. 11 8.0 3.0 Typ. 12 8.5 3.5 40 1.5 2.5 Max. 13 9.0 4.0 70 3.0 4.0 90 2.535 2.565 1.55 10.0 0.5 Unit V V V μA mA mA μA V V V mV mV μA μA μA Under-Voltage Lockout Section Supply Current Section VCC = VTH(start) – 0.2V Output no switching 50kHz, CL=1nF Vinv = 0V TA = 25°C 40 2.465 2.435 1.45 VCC = 14V~23V Vref1(1) Vinv = 1V~4V Vinv = 2.4V Vinv = 2.6V 4.5 0.7 90 TA = 25°C 1.24 3.0 Rmot = 13.7k Rmot = 13.7k, TA = 25°C 0.95 18.0 Threshold(1) -0.5 -12 12 5.5 1.0 115 1.30 4.5 1.00 22.5 6.5 1.3 140 1.36 6.0 1.05 27.0 65 2.500 2.500 1.50 0.1 20 Error Amplifier Section Vref1 Vref2 ΔVref1 ΔVref3 Ib(ea) Isource Isink Veao(H) Veao(Z) gm VTH(in) VTH(reset) Vmot tON-max Voltage Feedback Input Threshold1 Voltage Feedback Input Threshold2 Line Regulation Temperature Stability of Input Bias Current Output Source Current Output Sink Current Output Upper Clamp Voltage Zero Duty Cycle Output Voltage Transconductance(1) Output Voltage Selection Threshold Output Voltage Reset V V μmho V V V μs Maximum On-Time Section Maximum On-time Voltage Maximum On-time Programming Current Sense Input Threshold Voltage Limit Input Bias Current Current Sense Delay to Output (1) Current Sense Section VCS(limit) Ib(cs) td(cs) 0.7 VCS = 0V~1V -1.0 0.8 -0.1 350 0.9 1.0 500 V μA ns © 2005 Fairchild Semiconductor Corporation FAN7528 Rev. 1.0.6 5 www.fairchildsemi.com FAN7528 Dual-Output, Critical Conduction Mode PFC Controller Electrical Characteristics (Continued) VCC = 14V, TA = -40°C~125°C, unless otherwise specified. Symbol VTH(ZCD) HY(ZCD) Vclamp(h) Vclamp(l) Ib(ZCD) Isource(zcd) Isink(zcd) tdead Parameter Input Voltage Threshold(1) Detect Hysteresis (1) Condition Min. 1.35 0.05 Typ. 1.50 0.10 6.7 0.6 -0.1 Max. 1.65 0.15 7.4 1.0 1.0 -10 10 Unit V V V V μA mA mA ns Zero Current Detection Section Input High Clamp Voltage Input Low Clamp Voltage Input Bias Current Source Current Capability Sink Current Capability(1) Maximum Delay from ZCD to Output Turn-on(1) Output Voltage High Output Voltage Low Rising Falling Time(1) Time(1) (1) Idet = 3mA Idet = -3mA VZCD = 1V~5V 6.0 0 -1.0 100 200 Output Section VOH VOL tr tf VO(max) VO(uvlo) td(rst) VOVP HY(ovp) VTH(en) HY(en) IO = -100mA IO = 100mA CL = 1nF CL = 1nF VCC = 20V, IO = 100μA VCC = 5V, IO = 100μA 40 TA = 25°C 2.60 0.06 0.40 0.05 160 2.66 0.11 0.45 0.10 11.5 9.2 11.0 1.0 50 50 13.0 12.8 2.5 100 100 14.5 1 360 2.72 0.16 0.50 0.15 V V ns ns V V μs V V V V Maximum Output Voltage Output Voltage with UVLO Activated Restart Timer Delay OVP Threshold Voltage OVP Hysteresis Enable Threshold Voltage Enable Hysteresis Restart Timer Section Over-Voltage Protection Section Enable Section Note: 1. These parameters, although guaranteed by design, are not tested in production. © 2005 Fairchild Semiconductor Corporation FAN7528 Rev. 1.0.6 6 www.fairchildsemi.com FAN7528 Dual-Output, Critical Conduction Mode PFC Controller Typical Performance Characteristics 12.8 12.4 9.2 8.8 8.4 8.0 7.6 VTH(start) [V] 12.0 11.6 11.2 -60 -40 -20 0 20 40 60 80 100 120 140 VTH(stop) [V] -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] Temperature [°C] Figure 4. Start Threshold Voltage vs. Temp. Figure 5. Stop Threshold Voltage vs. Temp. 4.0 3.8 70 60 50 HY(uvlo) [V] IST [μA] 3.6 3.4 3.2 3.0 -60 -40 -20 0 20 40 60 80 100 120 140 40 30 20 10 0 -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] Temperature [°C] Figure 6. UVLO Hysteresis vs. Temp. Figure 7. Start-up Supply Current vs. Temp. 3.0 2.5 2.0 1.5 1.0 0.5 0.0 -60 -40 -20 0 20 40 60 80 100 120 140 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] IDCC [mA] ICC [mA] Temperature [°C] Figure 8. Operating Supply Current vs. Temp. Figure 9. Dynamic Operating Current vs. Temp. © 2005 Fairchild Semiconductor Corporation FAN7528 Rev. 1.0.6 7 www.fairchildsemi.com FAN7528 Dual-Output, Critical Conduction Mode PFC Controller Typical Performance Characteristics (Continued) 90 80 2.56 2.54 2.52 ICC(dis) [μA] 60 50 40 -60 -40 -20 0 20 40 60 80 100 120 140 Vref1 [V] 70 2.50 2.48 2.46 2.44 -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] Temperature [°C] Figure 10. ICC at Disable vs. Temp. Figure 11. Vref1 vs. Temp. 1.54 1.52 0.4 0.2 Ib(ea) [μA] Vref2 [V] 1.50 1.48 1.46 -60 -40 -20 0 20 40 60 80 100 120 140 0.0 -0.2 -0.4 -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] Temperature [°C] Figure 12. Vref2 vs. Temp. Figure 13. Input Bias Current vs. Temp. -6 -9 18 15 Isource [μA] Isink [μA] -12 -15 -18 -60 -40 -20 0 20 40 60 80 100 120 140 12 9 6 -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] Temperature [°C] Figure 14. Error Amp. Source Current vs. Temp. Figure 15. Error Amp. Sink Current vs. Temp. © 2005 Fairchild Semiconductor Corporation FAN7528 Rev. 1.0.6 8 www.fairchildsemi.com FAN7528 Dual-Output, Critical Conduction Mode PFC Controller Typical Performance Characteristics (Continued) 6.5 6.0 1.3 1.2 1.1 Veao(H) [V] 5.5 5.0 4.5 -60 -40 -20 0 20 40 60 80 100 120 140 Veao(Z) [V] 1.0 0.9 0.8 0.7 -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] Temperature [°C] Figure 16. Error Amp. Clamp Voltage vs. Temp. Figure 17. Zero Duty Output Voltage vs. Temp. 1.36 1.34 1.32 1.04 1.02 VTH(IN) [V] 1.30 1.28 1.26 1.24 -60 -40 -20 0 20 40 60 80 100 120 140 Vmot [V] 1.00 0.98 0.96 -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] Temperature [°C] Figure 18. Output Select Threshold vs. Temp. Figure 19. MOT Pin Voltage vs. Temp. 26 24 0.88 0.84 tON(max) [μs] VCS(limit) [V] -60 -40 -20 0 20 40 60 80 100 120 140 22 20 18 0.80 0.76 0.72 -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] Temperature [°C] Figure 20. Maximum On-Time vs. Temp. Figure 21. Current Limit vs. Temp. © 2005 Fairchild Semiconductor Corporation FAN7528 Rev. 1.0.6 9 www.fairchildsemi.com FAN7528 Dual-Output, Critical Conduction Mode PFC Controller Typical Performance Characteristics (Continued) 0.9 0.6 7.4 7.2 7.0 Vclamp(H) [V] -60 -40 -20 0 20 40 60 80 100 120 140 0.3 Ib(CS) [μA] 0.0 -0.3 -0.6 -0.9 6.8 6.6 6.4 6.2 6.0 -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] Temperature [°C] Figure 22. CS Input Bias Current vs. Temp. Figure 23. ZCD Input High Clamp vs. Temp. 1.0 0.8 0.8 0.4 Vclamp(L) [V] Ib(ZCD) [μA] -60 -40 -20 0 20 40 60 80 100 120 140 0.6 0.4 0.2 0.0 -0.4 -0.8 0.0 -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] Temperature [°C] Figure 24. ZCD Input Low Clamp vs. Temp. Figure 25. ZCD Input Bias Current vs. Temp. 12.5 12.0 11.5 2.5 2.0 1.5 VOH [V] 11.0 10.5 10.0 9.5 VOL [V] -60 -40 -20 0 20 40 60 80 100 120 140 1.0 0.5 0.0 -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] Temperature [°C] Figure 26. Output Voltage High vs. Temp. Figure 27. Output Voltage Low vs. Temp. © 2005 Fairchild Semiconductor Corporation FAN7528 Rev. 1.0.6 10 www.fairchildsemi.com FAN7528 Dual-Output, Critical Conduction Mode PFC Controller Typical Performance Characteristics (Continued) 14.5 14.0 13.5 1.0 0.8 VO(max) [V] 13.0 12.5 12.0 11.5 -60 -40 -20 0 20 40 60 80 100 120 140 VO(uvlo) [V] 0.6 0.4 0.2 0.0 -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] Temperature [°C] Figure 28. Maximum Output Voltage vs. Temp. Figure 29. Output Voltage when UVLO vs. Temp. 400 350 300 2.74 2.72 2.70 td(rst) [μs] 200 150 100 50 -60 -40 -20 0 20 40 60 80 100 120 140 VOVP [V] 250 2.68 2.66 2.64 2.62 2.60 -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] Temperature [°C] Figure 30. Restart Timer Delay vs. Temp. Figure 31. Over-Voltage Protection vs. Temp. 0.14 0.12 0.50 0.48 HY(OVP) [V] 0.10 0.08 0.06 -60 -40 -20 0 20 40 60 80 100 120 140 VTH(en) [V] 0.46 0.44 0.42 0.40 -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] Temperature [°C] Figure 32. OVP Hysteresis vs. Temp. Figure 33. Enable Threshold Voltage vs. Temp. © 2005 Fairchild Semiconductor Corporation FAN7528 Rev. 1.0.6 11 www.fairchildsemi.com FAN7528 Dual-Output, Critical Conduction Mode PFC Controller Typical Performance Characteristics (Continued) 0.14 0.12 HY(en) [V] 0.10 0.08 0.06 -60 -40 -20 0 20 40 60 80 100 120 140 Temperature [°C] Figure 34. Enable Hysteresis vs. Temp. © 2005 Fairchild Semiconductor Corporation FAN7528 Rev. 1.0.6 12 www.fairchildsemi.com FAN7528 Dual-Output, Critical Conduction Mode PFC Controller Applications Information 1. Error Amplifier Block The error amplifier block has several functions, such as dual output function, over-voltage protection function, and disable function. 1.2 Over-Voltage Protection Function The control speed of the PFC converter is very slow; therefore, the over-voltage protection (OVP) of the output voltage is very important. The FAN7528 provides a precise OVP function that shuts down the drive circuit when the INV pin voltage exceeds 2.66V and there is 0.11V hysteresis. 1.1 Dual-Output Function Unlike conventional CRM PFC controllers, the FAN7528 has the dual-output control function according to the AC line voltage without sensing the rectified AC line voltage. Because the output voltage of the boost converter is proportional to the peak voltage of the input AC line voltage before the boost converter starts switching, the INV pin voltage represents the peak AC line voltage. When the AC line is connected to the boost converter, VCC voltage starts to increase from zero voltage. If the VCC voltage reaches 8.5V, the dual-output reference generator compares the INV pin voltage with 1.3V reference and, if the INV pin voltage is lower than 1.3V, the dual-output reference generator sets the reference voltage of the error amplifier to 1.5V. If the INV pin voltage is higher than 1.3V, the reference voltage is set to 2.5V. That means if the output voltage of the boost converter is set to 400V at high line, the output voltage is 240V (400V*1.5/2.5) at low line. If the output voltage is set to 390V at high line, the output voltage is 234V at low line. Because this block does not need the input voltage sensing network, the power loss and cost related with the sensing network can be saved. The reference voltage of the error amplifier is not reset until VCC goes below 4.5V. 2.66V OVP 2.55V 1.3 Disable Function If the INV pin voltage is lower than 0.45V, most of the internal block is disabled, the operating current is reduced to be 65µA, and there is 0.1V hysteresis in the comparator. 1.4 Error Amplifier The error amplifier is a transconductance type amplifier. The output current of the amplifier is proportional to the voltage difference between the inverting input and the non-inverting input of the amplifier. Some resistors and capacitors should be connected to the error amplifier output pin, the COMP pin, for the output voltage loop compensation. 2. Zero Current Detection Block The zero current detector (ZCD) generates the turn-on signal of the MOSFET when the boost inductor current reaches zero using an auxiliary winding coupled with the inductor. If the voltage of the ZCD pin goes higher than 1.5V, the ZCD comparator waits until the voltage goes below 1.4V. If the voltage goes below 1.4V, the zero current detector turns on the MOSFET. The ZCD pin is protected internally by two clamps, 6.7V high clamp and 0.6V low clamp. The 160µs timer generates a MOSFET turn-on signal if the drive output has been low for more than 160µs from the falling edge of the drive output. Disable 0.45V 0.35V Dual-Output Reference Generator Error Amp Gm VOUT VIN ZCD RZCD 5 6.7V 1.4V 1.5V Zero Current Detector R FAN7528 Rev. 1.00 S Q 160μ s Timer Turn-on Signal 1.5V/2.5V 1 INV 2 COMP Figure 36. Zero Current Detector Block FAN7528 Rev. 1.00 Figure 35. Error Amplifier Block © 2005 Fairchild Semiconductor Corporation FAN7528 Rev. 1.0.6 13 www.fairchildsemi.com FAN7528 Dual-Output, Critical Conduction Mode PFC Controller 3. Sawtooth Generator Block The output of the error amplifier and the output of the sawtooth generator are compared to determine the MOSFET turn-off instance. The slope of the sawtooth is determined by an external resistor connected to the MOT pin. The voltage of the MOT pin is 1V and the slope is proportional to the current flowing out of the MOT pin. The internal ramp signal has 1V offset; therefore, the drive output is shut down if the voltage of the COMP pin is lower than 1V. The MOSFET on-time is maximum when the COMP pin voltage is 5V. According to the slope of the internal ramp, the maximum on-time can be programmed. The necessary maximum on-time depends on the boost inductor, lowest AC line voltage, and maximum output power. The resistor value should be designed properly. Off Signal MOT 3 1V Sawtooth Generator 1V 4. Over-Current Protection Block The MOSFET current is sensed using an external sensing resistor for the over-current protection. If the CS pin voltage is higher than 0.8V, the over-current protection comparator generates a protection signal. An internal RC filter is included to filter switching noise. 40k CS 4 8pF 0.8V Over-Current Protection Comparator FAN7528 Rev. 1.00 OCP Signal Figure 38. Over-Current Protection Block 5. Switch Drive Block The FAN7528 contains a single totem-pole output stage designed for a direct drive of power MOSFET. The drive output is capable of up to 400mA peak current with a typical rise and fall time of 50ns with 1nF load. The output voltage is clamped to be 13V to protect MOSFET gate even if the VCC voltage is higher than 13V. Error Amp Output FAN7528 Rev. 1.00 Figure 37. Sawtooth Generator Block 6. Under-Voltage Lockout Block If the VCC voltage reaches 12V, the IC’s internal blocks are enabled and start operation. If the VCC voltage drops below 8.5V, most of the internal blocks are disabled to reduce the operating current. VCC voltage should be higher than 8.5V under normal conditions. © 2005 Fairchild Semiconductor Corporation FAN7528 Rev. 1.0.6 14 www.fairchildsemi.com FAN7528 Dual-Output, Critical Conduction Mode PFC Controller Typical Application Circuit Application Adapter Output power 100W Input voltage Universal input (90~264 Vac) Output voltage 389V/232V Features High efficiency (>90% at 90 Vac input) Low THD (total harmonic distortion) (