NCP1605 Enhanced, High Voltage and Efficient Standby Mode, Power Factor Controller The NCP1605 is a controller that exhibits near−unity power factor while operating in fixed frequency, Discontinuous Conduction Mode (DCM) or in Critical Conduction Mode (CRM). Housed in a SOIC−16 package, the circuit incorporates all the features necessary for building robust and compact PFC stages, with a minimum of external components. In addition, it integrates the skip cycle capability to lower the standby losses to a minimum. • • • Near−Unity Power Factor Fixed Frequency, Discontinuous Conduction Mode Operation Critical Conduction Mode Achievable in Most Stressful Conditions Lossless High Voltage Current Source for Startup Soft Skipt Cycle for Low Power Standby Mode Switching Frequency up to 250 kHz Synchronization Capability Fast Line / Load Transient Compensation Valley Turn On High Drive Capability: −500 mA / +800 mA Signal to Indicate that the PFC is Ready for Operation (“pfcOK” Pin) VCC range: from 10 V to 20 V Follower Boost Operation This is a Pb−Free Device Safety Features • • • • • • • Output Under and Overvoltage Protection Brown−Out Detection Soft−Start for Smooth Startup Operation Overcurrent Limitation Zero Current Detection Protecting the PFC stage from Inrush Currents Thermal Shutdown Latched Off Capability Typical Applications • PC Power Supplies • All Off Line Appliances Requiring Power Factor Correction © Semiconductor Components Industries, LLC, 2007 February, 2007 − Rev. 1 MARKING DIAGRAM 1 16 General Features • • • • • • • • • • • http://onsemi.com 1 SOIC−16 D SUFFIX CASE 751B NCP1605 AWLYWWG 1 A WL Y WW G = Assembly Location = Wafer Lot = Year = Work Week = Pb−Free Package PIN CONNECTIONS STBY 1 16 HV BO 2 15 NC Vcontrol 3 14 OVP/UVP FB 4 13 STDWN CSin 5 12 pfcOK/REF5V CSout/ZCD 6 11 VCC Ct 7 10 DRV OSC/SYNC 8 9 GND (Top View) ORDERING INFORMATION Device Package NCP1605DR2G SOIC−16 (Pb−Free) Shipping† 2500/Tape & Reel †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specification Brochure, BRD8011/D. Publication Order Number: NCP1605/D NCP1605 Rout1 Rbo1 Rout2 Vout STBY control Rbo2 Rovp1 1 16 2 15 Cbo 3 14 FB CVctrl CVCC 6 11 7 10 Ct Vout D1 8 VCC CVref pfcOK LOAD M1 Cbulk + 9 Cosc Rocp L1 Rovp2 OVP 5 12 Ac line EMI Filter Icoil + 4 13 Rzcd Cin Vin VCC Rdrv Icoil Rcs Figure 1. MAXIMUM RATINGS Pin Rating Symbol Value Unit 10 Power Supply Input VCC −0.3, +20 V 10 The maximum transient voltage (Note 1) VCC −0.3, +25 V 1, 2, 4, 6, 7, 8, 13 and 14 Input Voltage VI −0.3, +9 V 3 VCONTROL Pin VCONTROL −0.3, VCONTROL MAX (Note 1) V 16 High Voltage Pin HV −0.3, +500 V PD RqJA 550 145 mW °C/W Power Dissipation and Thermal Characteristics: Maximum Power Dissipation @ TA = 70°C Thermal Resistance Junction−to−Air TJ −40, +125 °C Maximum Junction Temperature TJmax 150 °C Storage Temperature Range TSmax −65 to 150° °C Lead Temperature (Soldering, 10 s) TLmax 300 °C Operating Junction Temperature Range Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. 1. “VCONTROLMAX” is the pin clamp voltage http://onsemi.com 2 NCP1605 Typical Electrical Characteristics Table(s) (Conditions: VCC = 16 V, VHV = 50 V, VPin2 = 2 V, VPin13 = 0 V, TJ from 0°C to +125°C, unless otherwise specified) (Note 2) Symbol Rating Min Typ Max Unit Gate Drive Section Trise Output Voltage Rise Time @ CL = 1 nF, from 1 V to 10 V − 40 − ns Tfall Output Voltage Fall Time @ CL = 1 nF, from 10 V to 1 V − 20 − ns ROH Source Resistance @ IPin10 = 100 mA − 15 25 W Source Current capability (@ VPin10 = 0 V) − 500 − mA ROL Sink Resistance @ IPin10 = 100 mA − 7 15 W Isink Sink Current Capability (@ VPin10 = 10 V) − 800 − mA 2.425 2.500 2.575 V − ±20 − mA Isource Regulation Block VREF Voltage Reference IEA Error Amplifier Current Capability GEA Error Amplifier Gain 100 200 300 mS Pin 1 Bias Current @ VPin1 = VREF −500 − 500 nA − − 2.7 3.6 0.6 3.0 − − 3.3 IBPin1 VCONTROL − VCONTROLMAX − VCONTROLMIN − D VCONTROLl Pin 2 Voltage: V − @ VPin4 = 2 V − @ VPin4 = 3 V VOUTL / VREF Ratio (VOUT Low Detect Threshold / VREF) (Note 5) 95.0 95.5 96.0 % HOUTL / VREF Ratio (VOUT Low Detect Hysteresis / VREF) (Note 5) − − 0.5 % Pin 2 Source Current when (VOUT Low Detect) is activated 190 240 290 mA ILEAKAGE Current Sourced by Pin 13 @ VPin14 = 2.3 V −500 − 500 nA VSTDWN Pin 13 Threshold for Shutdown 2.375 2.500 2.625 V Overvoltage Protection Threshold 2.425 2.500 2.575 V VOVP / VREF Ratio (VOVP / VREF) (Note 4) 99.5 100.0 100.5 % VUVP / VREF Ratio UVP threshold over VREF 8 12 16 % @ VPin14 = VOVP @ VPin14 = VUVP −500 −500 − − 500 500 @ VPin4 = 1.00 V @ VPin4 = 1.75 V @ VPin4 = 2.50 V 54 156 313 60 182 370 69 214 428 − 5 − V 0.9 1 1.1 V IBOOST Shutdown Block Over and Under Voltage Protections VOVP IBPin14 Pin 13 Bias Current: nA Ramp Control mA Pin 7 Source Current: IRAMP − 1.00 V IRAMP − 1.75 V IRAMP − 2.50 V Vcl_ff VCLCRM RCT Pin 7 Clamp Voltage @ VPin4 = VPin2 = 2 V and VPin6 = 0 V Pin 7 Clamp Voltage @ VPin4 = 0 V, VPin2 = 2 V and VPin6 = 1 V Ratio (Pin 7 Clamp Voltage / (Pin 7 Charge Current) (VCLCRM / IRAMP) @ VPin6 = 0 V and kW − VPin4 = 1.00 V − VPin4 = 1.75 V − VPin4 = 2.50 V − − − 16.7 5.4 2.7 − − − 2. The maximum transient voltage with a corresponding maximum transient current at 100 mA. The maximum transient power handling capability must be observed as well. 3. The above specification gives the targeted values of the parameters. The final specification will be available once the complete circuit characterization has been performed. 4. Not tested; guaranteed by characterization 5. Not tested; guaranteed by design http://onsemi.com 3 NCP1605 Typical Electrical Characteristics Table(s) (Conditions: VCC = 16 V, VHV = 50 V, VPin2 = 2 V, VPin13 = 0 V, TJ from 0°C to +125°C, unless otherwise specified) (Note 2) Symbol Min Typ Max Unit Delay (VPin7 > 5 V) to (DRV low) − 90 200 ns CINT Average Pin 7 Internal Capacitance (VPin7 varying from 0 and 1 V) Guaranteed by design − 15 25 pF VINIT Maximum Pin 7 Voltage Allowing the Setting of the PWM Latch − 50 90 mV Pin 7 Sink Current (Drive low) @ VPin7 = 1 V − 10 − mA TONMIN IRAMP_SINK Rating Current Sense Block Off100 Current Sense Pin Voltage, 100 mA being drawn from Pin 5 −20 0 20 mV Off10 Current Sense Pin Voltage, 10 mA being drawn from Pin 5 3 8 13 mV IMAX Overcurrent Protection Threshold 230 250 265 mA TOCP (Ipin5 > 250 mA) to (DRV low) Propagation Delay (Note 4) − 100 200 ns KCS10 Ratio (IPin6/IPin5) @ IPin5 = 10 mA 99 108 117 % KCS200 Ratio (IPin6/IPin5) @ IPin5 = 200 mA 98 101 103 % VZCD Pin 6 Comparator Threshold 50 100 200 mV TZCD Delay from (VPin6 < VZCD) to (DRV high) − 120 240 ns VSTBY Standby Mode Threshold (VPin1 falling) 280 310 340 mV HSTBY Hysteresis for Standby Mode Detection 25 30 50 mV 99 100 101 % Standby Input VSKIPOUT / VOUTL Ratio (Pin 4 Voltage to terminate a SKIP period) over the (VOUT Low Detect Threshold) (Note 5) Oscillator / Synchronization Block Icharge Oscillator Charge Current 90 100 110 mA Idisch Oscillator Discharge Current 90 100 110 mA Vsync_H Comparator Upper Threshold − 3 − V Vsync_L Comparator Lower Threshold − 2 − V 0.9 1 1.1 V Minimum Synchronization Pulse Width for Detection − − 500 ns VpfcOKL Pin 12 Voltage @ VPin13 = 5 V, 250 mA being sunk by Pin 12 − 60 120 mV VpfcOKH Pin 12 Voltage @ VPin13 = 0 V and VPin3 = 5 V, with a 250 mA sourced by Pin 12 Pin 12 Voltage @ VPin13 = 0 V and VPin3 = 5 V, with a 5 mA sourced by Pin 12 4.7 5.0 5.3 V 4.5 5.0 5.3 5 10 − mA 0.9 1.0 1.1 V Swing Tsync_min Comparator Swing (Vsync_H − Vsync_L) pfcOK / REF5V Icap_ref Current Capability Brown−Out Detection Block VBOH Brown−Out Comparator Threshold (VPin2 rising) VBOL Brown−Out Comparator Threshold (VPin2 falling) 0.45 0.50 0.55 V IBBO Pin 6 Bias Current @ VPin2 = 0.5 V and 1 V −500 − 500 nA − 155 − °C Thermal Shutdown TLIMIT Thermal Shutdown Threshold 2. The maximum transient voltage with a corresponding maximum transient current at 100 mA. The maximum transient power handling capability must be observed as well. 3. The above specification gives the targeted values of the parameters. The final specification will be available once the complete circuit characterization has been performed. 4. Not tested; guaranteed by characterization 5. Not tested; guaranteed by design http://onsemi.com 4 NCP1605 Typical Electrical Characteristics Table(s) (Conditions: VCC = 16 V, VHV = 50 V, VPin2 = 2 V, VPin13 = 0 V, TJ from 0°C to +125°C, unless otherwise specified) (Note 2) Symbol HTEMP Rating Thermal Shutdown Hysteresis Min Typ Max Unit − 15 − °C VCC UNDERVOLTAGE Lockout Section VCCON Turn on Threshold Level, VCC Raising Up 14 15 16 V VCCOFF Minimum Operating Voltage after Turn−on 8 9 10 V Difference (VCCON − VCCOFF) 5 6 − V HUVLO VCCSTUP VCC Threshold below which the Startup Current Source Turns on 5.5 7.0 8.0 V HLATCHOFF Difference (VCCOFF − VCCSTUP) 0.6 2.0 − V 2 4 5 V High−Voltage Current Source (sunk by Pin 16), VCC = 13.5 V 5 12 20 mA Startup Charge Current flowing out of the VCC Pin, VCC = 13.5 V 5 12 20 mA High−Voltage Current Source, VCC = 0 V − 0.5 1.0 mA − 2.0 310 310 2.5 3.5 570 550 5 7 780 750 mA mA mA mA VCCRST VCC Level at which the Logic Resets Internal STARTUP Current Source IC1_hv IC1_Vcc IC2 Device Consumption Icc_op1 Icc_op2 Icc_OFF Icc_latchOFF Power Supply Current: Operating (@ VCC = 16 V, no load, no switching) Operating (@ VCC = 16 V, no load, switching) Off Mode (@ VCC = 16 V, Pin 6 grounded) Latched−Off Mode (@ VCC = 13.5 V and VPin13 = 5 V) 2. The maximum transient voltage with a corresponding maximum transient current at 100 mA. The maximum transient power handling capability must be observed as well. 3. The above specification gives the targeted values of the parameters. The final specification will be available once the complete circuit characterization has been performed. 4. Not tested; guaranteed by characterization 5. Not tested; guaranteed by design http://onsemi.com 5 NCP1605 PIN FUNCTION DESCRIPTION Pin Number Name Function 1 STBY An external signal (typically, a portion of the feedback signal of the downstream converter or a filtered portion of the SMPS drive pulses) should be applied to Pin 1. When the Pin 3 voltage goes below 300 mV, the circuit enters a burst mode operation where the bulk voltage varies between the regulation voltage and 95.5% of this level. 2 Brown−Out / Inhibition Apply a portion of the averaged input voltage to detect brown−out conditions. If VPin2 is lower than 0.5 V, the circuit stops pulsing until VPin2 exceeds 1 V (0.5 V hysteresis). Ground Pin 6 to disable the part. 3 VCONTROL / Soft−Start The error amplifier output is available on this Pin. The capacitor connected between this pin and ground adjusts the regulation loop bandwidth that is typically set below 20 Hz to achieve high Power Factor ratios. Pin 3 is grounded when the circuit is off so that when it starts operation, the power increases slowly (soft−start). 4 Feedback This pin receives a portion of the pre−converter output voltage. This information is used for the regulation and the “output low” detection (VOUTL) that drastically speed up the loop response when the output voltage drops below 95.5% of the wished level. 5 Current Sense Input This pin monitors a negative voltage proportional to the coil current. This signal is sensed to limit the maximum coil current and detect the core reset (coil demagnetization). 6 Current Sense Output This pin sources the Pin 5 current. Place a resistor between Pin 6 and ground to build the voltage proportional to the coil current and detect the core reset. The impedance between Pin 6 and ground should not exceed 3 times that of the Pin 5 to ground. You can further apply the voltage from an auxiliary winding to improve the valley detection of the MOSFET drain source voltage. 7 Ct (Ramp) The circuit controls the power switch on−time by comparing the Pin 7 ramp to an internal voltage (“Vton”) derived from the regulation block and the sensed “dcycle” (relative duration of the current cycle over the corresponding switching period). Pin 7 sources a current proportional to the squared output voltage to allow the Follower Boost operation (optional) where the PFC output voltage stabilizes at a level that varies linearly versus the ac line amplitude. This technique reduces the difference between the output and input voltages, to optimize the boost efficiency and minimize the size and cost of the PFC stage 8 Oscillator / synchronization Connect a capacitor or apply a synchronization signal to this pin to set the switching frequency. If the coil current cycle is longer than the selected switching period, the circuit delays the next cycle until the core is reset. Hence, the PFC stage can operate in CRM in the most stressful conditions. 9 GND Connect this pin to the pre−converter ground. 10 Drive The high current capability of the totem pole gate drive (+0.5/−0.8 A) makes it suitable to effectively drive high gate charge power MOSFETs. 11 VCC This pin is the positive supply of the IC. The circuit starts to operate when VCC exceeds 15 V and turns off when VCC goes below 9 V (typical values). After startup, the operating range is 10 V up to 20 V. 12 PfcOK / REF5V 13 STDWN 14 OVP / UVP 15 NC Creepage distance. 16 HV Connect Pin 16 to the bulk capacitor. The internal startup current source placed between Pin 16 and the VCC terminal, charges the VCC capacitor at startup. The Pin 12 voltage is high (5 V) when the PFC stage is in a normal, steady state situation and low otherwise. This signal serves to “inform” the downstream converter that the PFC stage is ready and that hence, it can start operation. Apply a voltage higher than 2.5 V on Pin 13 to permanently shutdown the circuit. This pin can be used to monitor the voltage across a thermistor in order to protect the application from an excessive heating and/or to detect an overvoltage condition. To resume operation, it is necessary to decrease the circuit VCC below VCCRST (4 V typically) by for instance, unplugging the PFC stage and replugging it after VCC is discharged. The circuit turns off when VPin14 goes below 480 mV (UVP) and disables the drive as long as the pin voltage exceeds 2.5 V (OVP). http://onsemi.com 6 NCP1605 2.59 265 2.57 260 2.55 255 IREF, (mA) VREF, (V) 2.53 2.51 2.49 2.47 250 245 2.45 240 2.43 2.41 −40 −15 10 35 60 85 235 −40 110 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) Figure 2. Reference Voltage vs. Temperature Figure 3. Reference Current vs. Temperature 103 2.60 102 VOVP/VREF, (%) 2.56 2.52 2.48 2.44 101 100 99 98 2.40 −40 −15 10 35 60 85 97 −40 110 −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 4. Overvoltage Threshold vs. Temperature Figure 5. Ratio Overvoltage Threshold Overvoltage Reference vs. Temperature 2.61 2.56 VSTDWN, (V) VOVP, (V) −15 TJ, JUNCTION TEMPERATURE (°C) 2.51 2.46 2.41 2.36 −40 −15 10 35 60 85 TJ, JUNCTION TEMPERATURE (°C) 110 Figure 6. Shutdown Threshold vs. Temperature http://onsemi.com 7 NCP1605 0.6 0.5 15.16 VUVPVREF, (%) VUVP, (V) 0.4 0.3 0.2 13.12 11.08 9.04 0.1 0 −40 −15 10 35 60 85 7 −40 110 −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 7. Undervoltage Protection Threshold vs. Temperature Figure 8. Ratio (VUVP/VREF) vs. Temperature 15.4 9.7 9.4 15.1 VCCOFF, (V) VCCON, (V) 9.1 14.8 14.5 14.2 13.9 −40 8.8 8.5 8.2 −15 10 35 60 85 7.9 −40 110 −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 9. VCC Turn on Threshold vs. Temperature (VCC Raising Up) Figure 10. VCC Minimum Operating Voltage After Turn On 8.8 6.7 8.3 7.8 VCCSTUP, (V) HUVLO, (V) 6.4 6.1 5.8 7.3 6.8 6.3 5.8 5.5 5.3 5.2 −40 −15 10 35 60 85 4.8 −40 110 TJ, JUNCTION TEMPERATURE (°C) −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) Figure 11. Difference (VCCON − VCCOFF) vs. Temperature Figure 12. VCC Threshold Below which the Startup Current Source Turns on vs. Temperature http://onsemi.com 8 NCP1605 4 6 3.5 5 VCCRST, (V) HLATCHOFF, (V) 3 2.5 2 4 3 2 1.5 1 1 −15 10 35 60 85 0 −40 110 −15 10 35 60 85 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 13. Difference (VCCOFF−VCCSTUP) vs. Temperature Figure 14. VCC Level Below Which the Logic Resets vs. Temperature 20 20 18 18 16 16 IC1_VOFF, (mA) IC1_HV, (mA) 0.5 −40 14 12 10 14 12 10 8 8 6 6 4 110 4 −40 −15 10 35 60 85 110 −40 −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 15. High−Voltage Current Source (Sunk by Pin 16) vs. Temperature (@ VCC = 13.5 V) Figure 16. Startup Charge Current Flowing Out of the VCC Pin vs. Temperature (@ VCC = 13.5 V) 90 1.2 80 70 HV_LEAKAGE, (mA) IC2, (mA) 0.9 0.6 0.3 60 50 40 30 20 10 0 −40 0 −15 10 35 60 85 110 −40 −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 17. High−Voltage Current Source vs. Temperature (@ VCC = 0 V) Figure 18. Pin 16 Leakage Current vs. Temperature (@ VPIN16 = 500 V and VCC = 16 V) http://onsemi.com 9 24 −12 22 −14 IEA_SINK, (mA) IEA_SOURCE, (mA) NCP1605 20 18 16 −16 −18 −20 −22 14 12 −40 −15 10 35 60 85 −24 −40 110 −15 TJ, JUNCTION TEMPERATURE (°C) 35 60 85 110 Figure 20. Sink Current Capability of the Error Amplifier vs. Temperature 300 150 260 100 220 50 IBPIN4, (nA) GEA, (mS) Figure 19. Source Current Capability of the Error Amplifier vs. Temperature 180 140 0 −50 100 −100 60 −40 −15 10 35 60 85 −150 −40 110 −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 21. Error Amplifier Gain vs. Temperature Figure 22. Feedback Pin Bias Current vs. Temperature (@ VPIN4 = VREF) 3.9 3.3 3.8 3.2 3.7 3.1 D(VCONTROL), (V) VCONTROLMAX, (V) 10 TJ, JUNCTION TEMPERATURE (°C) 3.6 3.5 3.4 2.9 2.8 2.7 3.3 3.2 −40 3 2.6 −15 10 35 60 85 110 −40 −15 10 35 60 85 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 23. VCONTROL Maximum Voltage vs. Temperature Figure 24. VCONTROL Maximum Swing (DVCONTROL) vs. Temperature http://onsemi.com 10 110 95.9 270 95.8 260 95.7 250 95.6 IBOOST, (mA) VOUTL/VREF, (%) NCP1605 95.5 95.4 240 230 220 95.3 210 95.2 200 95.1 190 −40 −15 10 35 60 85 110 −40 TJ, JUNCTION TEMPERATURE (°C) 105 105 100 100 IDISCH, (mA) ICHARGE, (mA) 110 95 90 85 85 35 60 85 80 −40 110 110 −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) Figure 27. Oscillator Charge Current vs. Temperature Figure 28. Oscillator Discharge Current vs. Temperature 150 125 pfcOK_L (mV) 0.99 SWING, (V) 85 TJ, JUNCTION TEMPERATURE (°C) 1.01 0.97 0.95 0.93 0.91 −40 60 95 90 10 35 Figure 26. Pin 3 Source Current when (VOUT Low Detect Threshold) is Activated vs. Temperature 110 −15 10 TJ, JUNCTION TEMPERATURE (°C) Figure 25. Ratio (VOUT Low Detect Threshold) / VREF vs. Temperature 80 −40 −15 100 75 50 25 −15 10 35 60 85 0 −40 110 TJ, JUNCTION TEMPERATURE (°C) −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) Figure 29. Oscillator Swing vs. Temperature Figure 30. pfcOK Pin Low Level Voltage vs. Temperature http://onsemi.com 11 5.5 5 5.3 4 ICC_OP1, (mA) pfcOK_H, (V) NCP1605 5.1 4.9 4.7 2 1 4.5 −40 −15 10 35 60 85 0 −40 110 −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 31. pfcOK Pin High Level Voltage vs. Temperature (250 mA Load) Figure 32. Operating Consumption vs. Temperature (VCC = 16 V, No Load, No Switching) 800 5 700 ICCOFF, (mA) 6 4 3 600 500 400 2 1 −40 −15 10 35 60 85 300 −40 110 −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 33. Operating Consumption vs. Temperature (VCC = 16 V, No Load, Switching) Figure 34. Off Mode Consumption vs. Temperature (VCC = 16 V, Pin 2 Grounded) 800 700 ICCSTDOWN, (mA) ICC_OP2, (mA) 3 600 500 400 300 −40 −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) Figure 35. Shutdown Mode Consumption vs. Temperature (VCC = 16 V, Pin 2 GND) http://onsemi.com 12 NCP1605 1.05 0.55 VCBOL, (V) 0.6 VCBOH, (V) 1.1 1 0.95 0.5 0.45 0.9 0.4 −40 −15 10 35 60 85 110 −40 −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 36. Brown−Out Upper Threshold vs. Temperature Figure 37. Brown−Out Lower Threshold vs. Temperature 14 14 12 12 8 OFF10, (mV) OFF100, (mV) 10 6 4 10 8 6 2 4 0 −2 2 −40 −15 10 35 60 85 110 −40 −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 38. Current Sense Pin Voltage vs. Temperature (100 mA Being Drawn from Pin 5) Figure 39. Current Sense Pin Voltage vs. Temperature (10 mA Being Drawn from Pin 5) 68 208 66 203 IRAMP_1.75 V, (mA) IRAMP_1.00 V, (mA) 198 64 62 60 58 56 193 188 183 178 173 168 54 163 158 −40 52 −40 −15 10 35 60 85 110 −15 10 35 60 85 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 40. Pin 7 Source Current @ VPIN4 = 1.0 V vs. Temperature Figure 41. Pin 7 Source Current @ VPIN4 = 1.75 V vs. Temperature http://onsemi.com 13 110 NCP1605 8 415 405 7 385 RCT (kW) IRAMP_2.50 V, (mA) 395 375 365 6 5 355 345 4 335 325 −40 −15 10 35 60 85 3 −40 110 −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 42. Pin 7 Source Current @ VPIN4 = 2.5 V vs. Temperature Figure 43. Ratio Pin 7 Clamp Voltage / (Pin 7 Charge Current) that is (VCLCRM / IRAMP) @ VPIN6 = 0 V and VPIN4 = 1.75 V 112 200 180 160 VZCD, (mV) Kcs10, (%) 110 108 106 140 120 100 80 60 104 −40 −15 10 35 60 85 40 −40 110 −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 44. Ratio (IPIN6 / IPIN5) @ IPIN5 = 10 mA vs. Temperature Figure 45. Pin 6 Comparator Threshold vs. Temperature 220 340 200 330 180 320 VSKIPH, (V) TZCD, (ns) 160 140 120 100 310 300 290 80 280 60 270 40 −40 −15 10 35 60 85 260 −40 110 −15 10 35 60 85 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 46. Delay from (ZCD Pin Low) to (DRV High) vs. Temperature Figure 47. Skip Cycle Threshold (VPIN1 Falling) vs. Temperature http://onsemi.com 14 110 26 160 24 140 22 120 20 ROH, (W) 180 100 80 18 16 60 14 40 12 20 10 0 −40 −15 10 35 60 85 8 −40 110 −15 10 35 60 85 110 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 48. Minimum On−Time vs. Temperature Figure 49. Gate Drive Source Resistance vs. Temperature 16 14 12 ROL, (W) tOMIN, (ns) NCP1605 10 8 6 4 2 −40 −15 10 35 60 85 TJ, JUNCTION TEMPERATURE (°C) 110 Figure 50. Gate Drive Sink Resistance vs. Temperature http://onsemi.com 15 NCP1605 Vout Low Detect 200 mA VoutL + − 95.5% Vref All the RS latches are RESET dominant HVCS_ON HV UVLO pfcOK Error Amplifier VSTBY − + ±20 mA Vref FB VDD UVLOs Latch Reset Internal Thermal Shutdown TSD UVLO (Vcc<VccOFF) V/I Iout FLAG1 UVP HVCS_ON NC OFF Vcontrol OFF BO_NOK STDWN SKIP 3V FLAG1 2.R VREGUL R LSTBY S Q R − + STBY + VSTBY 300 mV OVP Vref Vton processing circuitry VDD SKIP DT VREGUL pfcOK VoutL FAULT Management Regul VCC Iref Vt(on) − + Ich=K.Iout.Iout PWM Comparator SKIP OFF OVP OCP Ct VCC outON R R R Q R PWM S Latch Output Buffer Drv outON CLK BO / Stdwn − + 1 V / 0.5 V outON Ics > 250 mA − + 100 mV + − ZCD ZCD REF5V pfcOK OVP 12% Vref − + UVP + − OVP Vref stdwn − + S Q R Vcc<VccRST STDWN Figure 51. Block Diagram http://onsemi.com 16 pfcOK / REF5V S Lstup Q R FLAG1 OFF Vovp = Vref OSC / SYNC Q R Dead−time Detection Latch S OCP Ics CSout Ct_OK Oscillator / Synchronization Block DT Ics CSin 50 mV BO_NOK − + GND NCP1605 Detailed Operating Description Introduction − The NCP1605 disables the drive to stop delivering power as long as the output voltage exceeds the Overvoltage Protection (OVP) level. − The NCP1605 drastically speeds up the regulation loop when the output voltage is below 95.5% of its regulation level. This function is allowed only after the PFC stage has started up not to eliminate the soft−start effect. PFC OK: the circuit detects when the circuit is in normal situation or if on the contrary, it is in a startup or fault condition. In the first case, Pin 12 is in high state and low otherwise. Pin 12 serves to control the downstream converter operation in response to the PFC state. Safety Protections: the NCP1605 permanently monitors the input and output voltages, the coil current and the die temperature to protect the system from possible over−stresses and make the PFC stage extremely robust and reliable. In addition to the aforementioned OVP protection, one can list: − Maximum Current Limit and Zero Current Detection: the circuit permanently senses the coil current and immediately turns off the power switch if it is higher than the set current limit. It also prevents any turn on of the power switch as long as some current flows through the coil, to ensure operation in DCM. This feature also protects the MOSFET from the excessive stress that could result from the large in−rush currents that occurs during the startup phases. − Undervoltage Protection: the circuit turns off when it detects that the output voltage goes below 12% of the OVP level (typically). This feature protects the PFC stage from starting operation in case of too low ac line conditions or in case of a failure in the OVP monitoring network (e.g., bad connection). − Brown−Out Detection: the circuit detects too low ac line conditions and stop operating in this case. This protection protects the PFC stage from the excessive stress that could damage it in such conditions. − Thermal Shutdown: an internal thermal circuitry disables the circuit gate drive and then keeps the power switch off when the junction temperature exceeds 150°C typically. The circuit resumes operation once the temperature drops below about 100°C (50°C hysteresis). Output Stage Totem Pole: the NCP1605 incorporates a −0.5 A / +0.8 A gate driver to efficiently drive most TO220 or TO247 power MOSFETs. The NCP1605 is a PFC driver designed to operate in fixed frequency, Discontinuous Conduction Mode (DCM). In the most stressful conditions, Critical Conduction Mode (CRM) can be achieved without power factor degradation and the circuit could be viewed as a CRM controller with a frequency clamp (given by the oscillator). Finally, the NCP1605 tends to give the best of both modes without their respective drawbacks. Furthermore, the circuit incorporates protection features for a rugged operation together with some special circuitry to lower the power consumed by the PFC stage in no load conditions. More generally, the NCP1605 functions make it the ideal candidate in systems where cost−effectiveness, reliability, low standby power and high power factor are the key parameters: • Compactness and Flexibility: the controller requires few external components while offering a large variety of functions. Depending on the selected coil and oscillator frequency you select, the circuit can: 1. Mostly operate in CRM and use the oscillator as a frequency clamp. 2. Mostly operate in fixed frequency mode and only run in CRM at high load and low line. 3. Permanently operate in fixed frequency mode DCM. In all cases, the circuit provides near−unity power factor. Skip−cycle capability for low power standby: among other applications, the circuit targets power supply where the PFC stage must keep alive even in standby. A continuous flow of pulses is not compatible with no−load standby power requirements. Instead, the controller slices the switching pattern in bunch of pulses to drastically reduce the overall losses. The skip cycle operation is initiated by applying to Pin 1, a signal that goes below 300 mV in standby. Typically, this signal is drawn from the feedback of the downstream converter. Startup Current Source and large VCC range: meeting low standby power specifications represents a difficult exercise when the controller requires an external, lossy resistor connected to the bulk capacitor. The controller disables the high−voltage current source after startup which no longer hampers the consumption in no−load situations. In addition, the large VCC range (10 V to 20 V after startup), highly eases the circuit biasing. Fast Line / Load Transient Compensation: given the low bandwidth of the regulation block, the output voltage of PFC stages may exhibit excessive over and undershoots because of abrupt load or input voltage variations (e.g. at startup). If the output voltage is too far from the regulation level: http://onsemi.com 17 NCP1605 NCP1605 Operation Modes • • • DCM. It is worth noting that jumps between the CRM and modes cause absolutely no degradation: the input current keeps being properly shaped and there is no discontinuity in the power transfer. Given the dead−time presence, DCM needs a higher peak inductor current compared to CRM for the same delivered power. Hence, the coil is generally designed to have CRM at the most stressful conditions while DCM limits the switching frequency at lower load. The circuit can also transition within an ac line cycle so that: • CRM reduces the current stress around the sinusoid top. • DCM limits the frequency around the line zero crossing. This capability offers the best of each mode without the drawbacks. The way the circuit modulates the MOSFET on−time allows this facility. Like the NCP1601, the NCP1605: Features a current sense block that prevents the PFC stage from operating in CCM: as long as the coil current is not null, the power switch is not allowed to turn on. Hence the circuit can only operate in either Fixed Frequency DCM or CRM. Features the capability to exhibit near−unity power factor while operating in any type of Discontinuous Conduction Mode operation: DCM or CRM. Auto adapts: if there is some current flowing through the coil when the clock occurs to initiate a new current cycle, the PFC stage enters CRM. On the other hand, if the clock occurs during dead−times, one obtains a fixed frequency operation DCM. Thanks to its special oscillator/synchronization arrangement, the circuit automatically enters the appropriate mode CRM or Current Inductor Current, IL Input Current, Iin Time DCM Critical Mode DCM Figure 52. DCM and CRM Operation Within a Sinusoid Cycle The NCP1605 can jump from DCM to CRM within a sinusoid cycle (and vice versa) without any discontinuity in the current shaping or the power transfer. NCP1605 On−time Modulation One can show (refer to NCP1601 data sheet) that the ac line current is given by: Let’s study the ac line current absorbed by the PFC boost. The initial inductor current of each switching cycle is always zero. The coil current ramps up when the MOSFET is on. The slope is (VIN/L) where L is the coil inductance. At the end of the on−time (t1), the coil demagnetization phase starts. The coil current ramps down until this sequence ends when it reaches zero. The duration of this phase is (t2). The system enters then the dead−time (t3) that lasts until the next clock is generated. Iin + Vin ƪt1 (t21T)L t2)ƫ (eq. 1) Where T = (t1 + t2 + t3) is the switching period and VIN is the ac line rectified voltage. To the light of this equation, we immediately note that IIN is proportional to VIN if [t1(t1 + t2)/T] is a constant. http://onsemi.com 18 NCP1605 Iin Vin Inductor Current L Vout Ipk t1 Figure 53. PFC Boost Converter Cpin7 @ VTON Ipin7 (eq. 2) Iin + k @ Vin where : k + constant + ƪ120Cpin7m @@LV@REGUL ƫ (Vpin2) (eq. 4) 2 The input current is then proportional to the input voltage. Hence, the ac line current is properly shaped. One can note that this analysis is also valid in the CRM case. This condition is just a particular case of this functioning where (t3 = 0), which leads to (t1 + t2 = T) and (VTON = VREGUL). That is why the NCP1605 automatically adapts to the conditions and jumps from DCM and CRM (and vice versa) without power factor degradation and without discontinuity in the power delivery. Remark: Like in the NCP1601, the “VTON processing circuit” is “informed” when there is an OVP condition, not to over−dimension VTON in that conditions. Otherwise, an OVP sequence would be viewed as a dead−time phase by the circuit and VTON would inappropriately increase to compensate it. Similarly, the “VTON processing circuit” is inhibited for a skip sequence not to over−dimension “VTON” in this case (refer to Figure 56). T @ VREGUL t ) t2 or : VTON @ 1 + VREGUL t1 ) t2 T (eq. 3) timing capacitor saw−tooth Ich PWM comparator + to PWM latch − PWM Comparator VREGUL Closed When Output Low Time Given the regulation low bandwidth of the PFC systems, (VCONTROL) and then (VREGUL) are slow varying signals. Hence, the (VTON * (t1 + t2)/T) term is substantially constant. Provided that in addition, (t1) is proportional to (VTON), equation (1) leads to: (Iin = k * Vin), where k is a constant. More exactly: The charge current that is sourced by Pin 7 [Ipin7 = 60 mA/V2 * (VPin4)2] is constant at a given input voltage (VPin4 is proportional to the output voltage). Cpin7 that is the capacitor connected between Pin 7 and ground is also a constant. Hence, the power factor correction is achieved when the VTON (t1 + t2)/T term is constant. The output of the regulation block (VCONTROL) is linearly changed into a signal (VREGUL) varying between 0 and 1 V. (VREGUL) is the voltage that is injected into the PWM section to modulate the MOSFET duty−cycle. However, like the NCP1601, the NCP1605 inserts some circuitry that processes (VREGUL) to form the signal (VTON) that is used in the PWM section instead of (VREGUL) (see Figure 56). (VTON) is modulated in response to the dead−time sensed during the precedent current cycles, that is, for a proper shaping of the ac line current (refer to NCP1601 data sheet). This modulation leads to: VTON + t3 Figure 54. Inductor Current in DCM The NCP1605 operates in voltage mode. As portrayed by Figure 55, the MOSFET on time t1 is controlled by the signal Vton generated by the regulation block and the Pin 4 ramp as follows: t1 + t2 T Vton R1 + OA1 Vton − Turns Off MOSFET Cramp IN1 SKIP S3 C1 OFF S1 OVP Vton −> Vton during (t1+t2) −> 0 V during t3 (dead−time) −> Vton*(t1+t2)/T in average S2 DT (high during dead−time) Ramp Voltage Figure 56. VTON Processing Circuit PWM Outtage The integrator OA1 amplifies the error between VREGUL and IN1 so that in average, (VTON*(t1+t2)/T) equates VREGUL. Figure 55. PWM Circuit and Timing Diagram http://onsemi.com 19 Vin (V) NCP1605 350,00 3,50 300,00 3,00 250,00 2,50 200,00 2,00 150,00 1,50 100,00 1,00 50,00 0,50 0,00 0,00 0 2 4 6 8 10 time (ms) 12 14 16 18 20 Figure 57. Input Voltage and On−time vs Time (example with FSW = 100 kHz, Pin =150 W, VAC = 230 V, L = 200 mH) Regulation Block and Low Output Voltage Detection A transconductance error amplifier with access to the inverting input and output is provided. It features a typical transconductance gain of 200 mS and a maximum capability of ±20 mA. The output voltage of the PFC stage is typically scaled down by a resistors divider and monitored by the inverting input (feedback pin − Pin 4). The bias current is minimized (less than 500 nA) to allow the use of a high impedance feedback network. The output of the error amplifier is pinned out for external loop compensation (Pin 3). Typically a capacitor in the range of 100 nF, is applied between Pin 3 and ground, to set the regulation bandwidth below 20 Hz, as need in PFC applications. Vout Low Detect 0.955*Vref − + Vref − + FB Vcontrol The swing of the error amplifier output is limited within an accurate range: • It is forced above a voltage drop (VF) by some circuitry. • It is clamped not to exceed 3.0 V + the same VF voltage drop. Hence, VPin3 features a 3 V voltage swing. VPin3 is then offset down by (VF) and divided by three before it connects to the “VTON processing block” and the PWM section. Finally, the output of the regulation is a signal (“VREGUL” of the block diagram) that varies between 0 and 1 V. VREGUL 200 mA pfcOK 1V Error Amplifier ±20 mA OVLflag1 + VF OFF 2R + VF VREGUL 3V 0V R VF Figure 58. Regulation Block 3 V + VF VCONTROL Figure 59. Correspondence between VCONTROL and VREGUL 200 mA current source to speed−up the charge of the compensation capacitor (Cpin3). Finally, it is like if the comparator multiplied the error amplifier gain by 10. One must note that this circuitry for undershoots limitation, is not enabled during the startup sequence of the PFC stage but only once the converter has stabilized (that is when the Provided the low bandwidth of the regulation loop, sharp variations of the load, may result in excessive over and undershoots. Overshoots are limited by the Overvoltage Protection (see OVP section). To contain the undershoots, an internal comparator monitors the feedback (VPin4) and when VPin4 is lower than 95.5% of its nominal value, it connects a http://onsemi.com 20 NCP1605 “pfcOK” signal of the block diagram, is high). This is because, at the beginning of operation, the Pin 3 capacitor must charge slowly and gradually for a soft−startup. Remark: As shown in block diagram, the circuitry for undershoots limitation is disabled as long as Pin 3 detects standby conditions (VPin3 < 300 mV). This is to suppress the risk of audible noise in standby thanks to the soft–start that softens the bursts. Hence, one obtains the Follower Boost characteristics. The “Follower Boost” is an operation mode where the pre−converter output voltage stabilizes at a level that varies linearly versus the ac line amplitude. This technique aims at reducing the gap between the output and input voltages to optimize the boost efficiency and minimize the cost of the PFC stage (refer to the MC33260 data sheet for more information, at: http://www.onsemi.com/pub/Collateral/MC33260−D.PDF ). Remark: the timing capacitor applied to Pin 7 is discharged and maintained grounded when the drive is low. Furthermore, the circuit compares the Pin 7 voltage to an internal reference 50 mV and prevents the PWM latch from being set as long as VPin7 is higher than this low threshold. This is to guarantee that the timing capacitor is properly discharged before starting a new cycle. On−Time Control for Maximum Power Adjustment As aforementioned, the NCP1605 processes the error amplifier output voltage to form a signal (VTON) that is used by the PWM section to control the on−time. (VTON) compensates the relative weight of the dead−time sequences measured during the precedent current cycles. During the conduction time of the MOSFET, Pin 7 sources a current that is proportional to the square of the voltage applied to Pin 4 (feedback pin). Practically, as Pin 4 receives a portion of the output voltage (VOUT), IPin7 is proportional to the square of VOUT. The MOSFET turns off when the Pin 7 voltage exceeds VTON. Hence, the MOSFET on−time (t1) is given by: t1 + Current Sense and Zero Current Detection The NCP1605 is designed to monitor a negative voltage proportional to the coil current. Practically, a current sense resistor (RCS) is inserted in the return path to generate a negative voltage proportional to the coil current (VCS). The circuit uses VCS for two functions: the limitation of the maximum coil current and the detection of the core reset (coil demagnetization). To do so, the circuit incorporates an operational amplifier that sources the current necessary to maintain the CS pin voltage null (refer to Figure 60). By inserting a resistor ROCP between the CS pin and RCS, we adjust the CS pin current as follows: Cpin7 VTON where k is a constant. k VOUT 2 The coil current averaged over one switching period is: V t (t1 ) t2) t ICOIL u T + IIN(t) + IN 1 T 2L Where IIN(t) and VIN(t) are the instantaneous input current and voltage, respectively, t2 is the core reset time and T is the switching period. Hence, the instantaneous input power is given by the following equation: * [RCS ICOIL] ) [ROCP Ipin5] + Vpin5 [ 0 Which leads to: Cpin7 VIN2 VTON (t1 ) t2) PIN(t) + VIN(t)IIN(t) + @ T 2 L k VOUT 2 R Ipin5 + CS ICOIL ROCP In other words, the Pin 5 current is proportional to the coil current. IPin5 is utilized as follows: • If IPin5 exceeds 250 mA, an overcurrent is detected and the PWM latch is reset. Hence, the maximum coil current is: As aforementioned, we have: VTON (t1 + t2)/T = VREGUL where VREGUL is the signal outputted by the regulation block. Hence, the average input power is: t PIN u+ Cpin7 Vac 2 V 2 L k VOUT 2 REGUL R (ICOIL)max + OCP 250 mA RCS The maximum value of VREGUL being 1 V, the maximum power that can be delivered is: t PIN u MAX + Cpin7 Vac 2 1V 2 L k VOUT2 • To the light of the last equations, one can note that the PFC power capability is inversely proportional to the square of the output voltage. One sees that if the power demand is too high to keep the regulation, (VREGUL=1V) and the power delivery depends on the output voltage level that stabilizes to the following value: VOUT + The propagation delay (Ipin5 higher than 250 mA) to (drive output low) is in the range of 100 ns, typically. The Pin 5 current is internally copied and sourced by Pin 6. Place a resistor (RPin6) between Pin 6 and ground to build a voltage proportional to the coil current. The circuit detects the core reset when VPin6 drops below 100 mV, typically. The Pin 6 voltage equating: Vpin6 + Ǹ Cpin7 1 V V 2 L k h POUT ac Rpin6 @ Rcs @ ICOIL , Rcs the coil current threshold for zero current detection is: Where: • POUT is the output power. • And h is the efficiency. ROCP 100 mV (ICOIL)zcd + 100 mV + @ (ICOIL)MAX + 400 W @ (ICOIL)MAX Rpin6 @ RCS Rpin6 @ 250 mA Rpin6 http://onsemi.com 21 NCP1605 Rdrv Rzcd Vin D1 Icoil 6 EMI Filter Vdd Cin Current Mirror Vdd Ics L1 CSout 100 mV + − ZCD Rsense output buffer M1 Vcc DRV Cbulk LOAD 10 Ics outON Vzcd Ics > 250 mA ≥ OCP Rocp CSin Vout S LdT Q R DT OCP (RESET of the PWM latch) 5 Icoil Figure 60. Current Sense Block The CS block performs the overcurrent protection and the zero current detection. It is recommended to: 1. Keep ROCP equal to or lower than 5 kW 2. Choose RZCD as high as possible but not bigger than (3 x ROCP). This is to avoid that the Pin 6 leakage prevents a proper zero current detection. For instance, if ROCP is 2.2 kW, RZCD should not exceed 6.6 kW. 3. Place a resistor RDRV between the drive pin and Pin 6 to ease the circuit detection by creating some over−riding at the turn on instant. RDRV should be selected in the range of 3 times RZCD. For instance, if RZCD is 6.2 kW, a 22 kW resistor can be used for RDRV. The propagation delay (VPin6 lower than 100 mV) to (drive output high) is in the range of 300 ns, typically. The Zero Current Detection: • Is used to detect the dead−time sequences (“DT” high) • and hence, to process (VTON) from the error amplifier output (VCONTROL). In other words, this is an input of the on−time modulation block. Prevents the MOSFET from turning on as long as the “DT” and “ZCD” signals are low. This is the case as long as some current flows through the coil. This delaying action on the output stage tends to make the MOSFET turn on at the valley. To further optimize the valley switching, one can apply the voltage of an auxiliary winding to Pin 6 (CSOUT). The voltage is compared to an internal 100 mV reference, so that ZCD turns high only if (VPin6 < 100 mV). Overvoltage Protection While PFC circuits often use one single pin for both the Overvoltage Protection (OVP) and the feedback, the NCP1605 dedicates one specific pin for the undervoltage and overvoltage protections. The NCP1605 configuration allows the implementation of two separate feedback networks (see Figure 62): − One for regulation applied to Pin 4. − Another one for the OVP function. Remarks: • A resistor can be placed between Pin 6 and ground to increase the ZCD precision. • It is worth highlighting that the circuit permanently • senses the coil current and that it prevents any turn on of the power switch as long as the core is not reset. This feature protects the MOSFET from the possible excessive stress it could suffer from, if it was allowed to turn on while a huge current flows through the coil. In particular, this scheme effectively protects the PFC stage during the startup phase when huge in−rush currents charge the output capacitor. In addition this detection method does not require any auxiliary winding. A simple coil can then be used in the PFC stage. http://onsemi.com 22 NCP1605 Vout (bulk voltage) Rout1 1 16 2 15 3 14 Rout3 FB Vout (bulk voltage) HV 1 16 2 15 Rout1 OVP 3 14 FB 4 13 5 12 Rout2 6 11 7 10 8 8 9 Rovp2 9 Figure 62. Configuration with Two Separate Feedback Networks The startup phase is detected by the latch “LSTUP” of the block diagram. “LSTUP” is set during each “off” phase so that its output (“STUP”) is high when the circuit enters an active phase. The latch is reset when the error amplifier stops charging its output capacitor, that is, when the output voltage of the PFC stage has reached its desired regulation level. At that moment, “STUP” falls down to indicate the end of the startup phase. • In case of a condition preventing the circuit from operating properly, i.e., during the VCC charge by the high voltage startup current source, in a Brown−out case or when one of the following major faults turns off the circuit: − Incorrect feeding of the circuit (“UVLO” high when VCC<VCCOFF, VCCOFF equating 9 V typically). − Excessive die temperature detected by the thermal shutdown. − Undervoltage Protection − Latched off of the circuit (when the “STDWN” pin, VPin13, exceeds 2.5 V). And “pfcOK/REF5V” is high when the PFC output voltage is properly and safely regulated. “pfcOK/REF5V” should be used to allow operation of the downstream converter. The double feedback configuration offers some up−graded safety level as it protects the PFC stage even if there is a failure of one of the two feedback arrangements. However, if wished, one single feedback arrangement is possible as portrayed by Figure 61. The regulation and OVP blocks having the same reference voltage, the resistance ratio Rout2 over Rout3 adjusts the OVP threshold. More specifically, The bulk regulation voltage is: Rout1 ) Rout2 ) Rout3 @ Vref Rout2 ) Rout3 The OVP level is: Vovp + 4 13 7 10 Figure 61. Configuration with One Feedback Network for Both OVP and Regulation Vout + Rovp1 OVP 5 12 6 11 Rout2 HV Rout1 ) Rout2 ) Rout3 @ Vref Rout2 The ratio OVP level over regulation level is: R Vovp + 1 ) out3 Vout Rout2 For instance, (VOVP = 105% * Vout) leads to the following constraint: (Rout3 = 5% * Rout2). As soon and as long as the circuit detects that the output voltage exceeds the OVP level, the power switch is turned off to stop the power delivery. Remark: Like in the NCP1601, the “VTON processing circuit” is “informed” when there is an OVP condition, not to over−dimension VTON in that conditions. Otherwise, an OVP sequence would be viewed as a dead−time phase by the circuit and VTON would inappropriately increase to compensate it (refer to Figure 56). Standby Management The NCP1605 automatically skips switching cycles when the power demand drops below a given level. This is accomplished by monitoring the Pin 1 voltage that must receive a voltage below 300 mV in light load conditions. Practically, a portion of the feedback signal of the downstream converter (or some other signal able to indicate that the power demand is low) should be applied to Pin 1. PfcOK / REF5V Signal The NCP1605 can communicate with the downstream converter. The signal “pfcOK/REF5V is high (5 V) when the PFC stage is in normal operation (its output voltage is stabilized at the nominal level) and low otherwise. More specifically, “pfcOK/REF5V” is low: • During the PFC stage startup, that is, as long as the output voltage has not yet stabilized at the right level. http://onsemi.com 23 NCP1605 PFC stage downstream converter Rectified AC line 1 16 2 15 + 3 14 4 13 + 5 12 VCC 6 11 SMPS controller 7 10 8 9 NCP1605 Standby Input Voltage C Feed−back of the downstream converter Figure 63. Signal for Standby Detection In normal operation, the circuit controls the continuous absorption of the line current necessary for matching the load power demand. When the voltage applied to Pin 1 goes below 300 mV: • The output pulses are blanked and Pin 3 (“VCONTROL”) is grounded. • The output of the PFC stage being not fed any more, it drops. When the output voltage goes below 95.5% of the regulation level, the circuit resumes operation until “FLAG1” becomes low (what means that the output voltage has exceeded the regulation level). • At that moment, if VPin1 is still below 300 mV, a new skipping phase starts. In other words, instead of continuously providing the output with a small amount of power, the circuit operates from time to time at a higher power level. As an example and to make it simple, instead of continuously supplying 1% of PMAX, the circuit can provide the load with 10% of PMAX for 10% of the time. The IC enters the so−called skip cycle mode, also named controlled burst operation. This burst operation is much more efficient compared to a continuous power flow as it drastically reduces the number of pulsations and therefore the switching losses associated to them. http://onsemi.com 24 NCP1605 VPin1 300 mV VCONTROL VOUT 95.5% of the Regulation Level SKIP VOUTL Drive Figure 64. Standby Management Remark: properly turn on and off the “COMP_OSC” comparator. Also the synchronization signal must be low impedance enough not to be distorted by the Pin 8 source and sink currents. • The “storing circuitry” that contains a latch and some gates. The raising edge of the “COMP_OSC” output sets the “CLOCK Generation” latch to turn high the “CLK” signal. If the timing capacitor of Pin 7 is properly discharged (VPin4 <50 mV leading to “CTOK” high), the PWM block is ready for a new cycle and “CLK” can force the signal “VSET” in high state. As a consequence, the PWM latch sets. In addition, “VSET” resets the “CLOCK Generation” latch to make it ready for the next oscillator cycle. The two inverters of Figure 66, simply generate some delay to ensure that “VSET” keeps high long enough to set the PWM latch and reset the “CLOCK Generation” latch (longer delay than that produced by the two gates, may actually be necessary). The oscillator / Synchronization block is designed to set the switching frequency. However, the coil current can possibly be non zero at the end of a clock period and the circuit would enter Continuous Conduction Mode (CCM) if the MOSFET turned on in that moment. In order to prevent CCM, the “storing circuitry” of the oscillator / synchronization block, memorizes the “COMP_OSC” rising edge (thanks to the “CLOCK Generation” latch) and delays the next MOSFET conduction time until the coil current has totally vanished (that is until the signal “DT” is high − “DT” is generated by the current sense block so that it is high during the dead−time and low otherwise). In other words, CRM operation is obtained (refer to Figure 65). • Skip cycle is not allowed during the PFC startup phase • • to avoid that it interferes with the soft−start. That is why, skip cycle is enabled only when “pfcOK” is high. Each working phase of the burst mode starts smoothly as Pin 3 is grounded at the beginning of it. This soft−start capability is effective to avoid the audible noise that could possibly result from such a burst operation. The circuit leaves the standby mode when the output voltage goes below 95.5% of its regulation level and VPin1 is above 330 mV (300 mV + 30 mV hysteresis). Oscillator / Synchronization Section The oscillator generates the clock signal to set the PWM latch and turn the MOSFET on. The oscillator frequency is set by the capacitor that is applied to Pin 8. Typically, 820 pF force about 60 kHz. The maximum allowable oscillator frequency is 250 kHz. The clock frequency can also be driven by an external synchronization signal. This block contains two main parts (refer to Figure 66): • The arrangement that consists of charging/discharging current sources, a switch and a comparator. When used in oscillator mode, a capacitor is connected between Pin 8 and ground. A current source (100 mA) charges the Pin 8 capacitor until its voltage exceeds VoscH. At that moment, the comparator (“COMP_OSC”) turns high and activates the discharge current source (200 mA). As a consequence, Pin 8 actually sinks 100 mA that discharge the oscillator capacitor to VoscL. At that moment, the comparator turns low and initiates a new charge phase. If the circuit is to be externally triggered, the synchronization signal must cross VoscL and VoscH to http://onsemi.com 25 NCP1605 delay Clock CLK (PWM latch SET input) 100 mA Clock Edge COMP_OSC + − Osc/Sync Set Signal 200 mA R CLOCK Generation Latch Q S Ct_OK VOSCH/VOSCL Inductor Current DT (”DT” is high during the dead−time) Time Discontinuous Mode Critical Mode Figure 65. Oscillator Timing Diagram Figure 66. Oscillator / Synchronization Block HV 16 HV 15 mA / 0 HVCS_ON 15 V / 7 V + − VCC 10 + 9V − + UVLO GND 9 Cvcc Auxiliary Winding (When high, ”UVLO” indicates that the circuit is not properly fed and it sets the Fault latch to turn off the circuit) Figure 67. The Current Source brings VCC above 15 V and then Turns Off Startup Sequence / VCC Management during the VCC charging phase and off for the rest of the time. Hence, it spends no power during the PFC stage operation and in particular, in light load conditions. That is why the NCP1605 helps meet the most stringent standby requirements. At the moment when the PFC stage is plugged to the mains outlet, the internal current source starts charging the VCC capacitor. More generally, the startup current source is enabled whenever VCC drops below VCCSTUP (7 V, typically). When VCC exceeds the VCCON level (typically 15 V), the current source turns off and the circuit starts pulsing. The energy stored by the VCC capacitor serves to feed the controller and some auxiliary supply must take over before VCC drops below VCCOFF (9 V, typically), that is, the level below which the circuit stops pulsing. Hence, the circuit starts operating when the VCC voltage exceeds 15 V and stops pulsing when VCC drops below 9 V. The 6 V hysteresis prevents erratic operation as the VCC crosses the 15 V threshold. Figure 67 shows the internal arrangement of this structure. One can note that the startup current source is on Remarks: • Some circuitry (not represented in Figure 67) limits • the HV pin current below 1 mA if the VCC voltage is nearly below 1 V. This protects the circuit when the VCC pin is accidentally grounded. The full current capability (around 15 mA) is obtained when VCC exceeds about 1 V. The circuit is also kept off when the startup current source is on to make a clear distinction between the VCC charge phase and the operating sequence (refer to “HVCS_ON” signal on block diagram). http://onsemi.com 26 NCP1605 Brown−Out Detection Vpin2 + The brown−out pin receives a portion of the input voltage (VIN). As VIN is a rectified sinusoid, a capacitor must integrate the ac line ripple so that a voltage proportional to the average value of (VIN) is applied to the brown−out pin. The brown−out block detects too low input voltage conditions. A hysteresis comparator monitors the Pin 2 voltage. Before operation, the PFC stage is off and the input bridge acts as a peak detector. Hence, the voltage applied to Pin 2 is: Vpin2 + Ǹ2 Vac Rbo2 2 Ǹ2 Vac , p Rbo1 ) Rbo2 i.e., about 64% of the previous value. Therefore, the same line magnitude leads to a VPin2 voltage that is 36% lower when the PFC is working than when it is off (refer to Figure 69). That is why the NCP1605 features a 50% hysteresis (VBOL = 50% VBOH). When the circuit starts operation, the input voltage equates the ac line peak. Hence, the initial threshold of the Brown−Out comparator, must be the upper one (VBO = VBOH = 1 V when the NCP1605 leaves the off mode). Rbo2 . Rbo1 ) Rbo2 When a brown−out condition is detected, the signal “BO_NOK” turns off the circuit (refer to block diagram). After the PFC stage has started operation, the input voltage becomes a rectified sinusoid and the voltage applied to Pin 2 is: Vin 400 Ac line EMI Filter Rbo1 Cin BO 1 V / 0.5 V Start of PFC Operation Ǹ2 @ Vac @ sin(Rt) VSIN + − BO_NOK 200 RCS Cbo2 Ǹ2 @ Vac Rbo2 0 Figure 68. Brown−Out Block Figure 69. Typical Input Voltage of a PFC Stage Thermal Shutdown (TSD) the voltage reference used for the regulation and the overvoltage protection. The circuit also incorporates a precise current reference (IREF) that allows the Overcurrent Limitation to feature a ±6% accuracy over the temperature range. An internal thermal circuitry disables the circuit gate drive and then keeps the power switch off when the junction temperature exceeds 150_C typically. The output stage is then enabled once the temperature drops below about 100_C (50_C hysteresis). The temperature shutdown keeps active as long as the circuit is not reset, that is, as long as VCC keeps higher than VCCRESET. The reset action forces the TSD threshold to be the upper one (150°C). This ensures that any cold startup will be done with the right TSD level. OFF Mode As previously mentioned, the circuit turns off in the following cases: • When the high voltage, startup current source charges the VCC capacitor. • When one of the following major faults is detected: • Incorrect feeding of the circuit (“UVLO” high when VCC<VCCOFF, VCCOFF equating 9 V typically). • Excessive die temperature detected by the thermal shutdown. • Brown−Out condition. • Undervoltage Protection. • VPin13 higher than 2.5 V (“STDWN” of the block diagram turns high). Generally speaking, the circuit turns off when the conditions are not proper for good operation. In this mode, the controller stops operating. The major part of the circuit sleeps and its consumption is minimized (< 500 mA). Output Drive Section The output stage contains a totem pole optimized to minimize the cross conduction current during high frequency operation. The gate drive is kept in a sinking mode whenever the Undervoltage Lockout is active or more generally whenever the circuit is off (i.e., when the “Fault Latch” of the block diagram is high or when the HV current source is on). Its high current capability (−500 mA/+800 mA) allows it to effectively drive high gate charge power MOSFET. Reference Section The circuit features an accurate internal reference voltage (VREF). VREF is optimized to be ±3% accurate over the temperature range (the typical value is 2.5 V). VREF is http://onsemi.com 27 NCP1605 • The Pin 3 capacitor is discharged and kept grounded More specifically, when the circuit is in OFF state: • The drive output is kept low • All the blocks are off except: 1. The UVLO circuitry that keeps monitoring the VCC voltage and controlling the startup current source accordingly. 2. The TSD (thermal shutdown) 3. The “STDWN” latch that stores its output state. 4. The Undervoltage Protection (“UVP”). 5. The brown−out circuitry. One must note that the comparator is reset during the latched−off phase so that its threshold is the upper one (1 V) when the circuit enters the active phase (refer to next “VCC sequences” section). 6. The high voltage, startup current source when the circuit is in startup phase (that is when VCC is lower than VCCSTUP). VCC Conditions • • along the OFF time, to initialize it for the next operating sequence, where it must be slowly and gradually charged to offer some soft−start. The “pfcOK” pin is grounded. The output of the “VTON processing block” is grounded VCC Sequences The following table summarizes the state of the circuit in accordance to the VCC level. “OFF” is Low “OFF” is High (no condition forces the circuit off) (due to some protection like the thermal shutdown) VCC exceeds VCCON ⇒ the circuit enters the working phase The startup current source is disabled The circuit is fully active The startup current source is disabled The circuit is in OFF state VCC drops below VCCOFF ⇒ the circuit enters the latched−off phase The circuit is in OFF state The brown−out block resets during the latched−off phase so that its comparator threshold is forced to be the upper one (1 V) The circuit is in OFF state The brown−out block resets during the latched−off phase so that its comparator threshold is forced to be the upper one (1 V) VCC goes below VCCSTUP ⇒ the circuit enters the startup phase The high voltage, startup current source turns on to charge VCC. The drive output and the “pfcOK” are in low state (the circuit is off) All the circuit blocks are reset except: The thermal shutdown (TSD) and the brown−out block that keep operating The “STDWN” latch. The high voltage, startup current source turns on to charge VCC. The drive output and the “pfcOK” are in low state (the circuit is off) All the circuit blocks are reset except: The thermal shutdown (TSD) and the brown−out block that keep operating The “STDWN” latch. VCC goes below VCCRESET ⇒ the circuit resets The high voltage, startup current source is on. The whole circuitry is reset including the “TSD” and the “STDWN” latch. After reset, the TSD threshold is 150°C and the output of the “STDWN latch” is low. The high voltage, startup current source is on. The whole circuitry is reset including the “TSD” and the “STDWN” latch. After reset, the TSD threshold is 150°C and the output of the “STDWN latch” is low. The figures on the following pages portray the circuit behavior during a startup phase: • In case of normal conditions (Figure 70). • As a function of the brown−out pin voltage (Figure 71). http://onsemi.com 28 NCP1605 Remarks: The VCONTROL signal does not necessarily reach its clamp level (3.7 V) depending of the load and of the system time constants. In particular, if the circuit starts operation in light load and if the bulk capacitor is not too large, the output voltage VOUT generally exceeds the regulation level while VCONTROL keeps below its upper limit. The output voltage exhibits a 100 or 120 Hz ripple (at twice the line frequency). This ripple is also present in the VCONTROL voltage even if it is attenuated due to the regulation low bandwidth. Like that of VOUT, this ripple is not represented in Figure 70, for the sake of the clarity. VCCON VCC VCCOFF VCCSTUP 1V VOUT VOUT Regulation Level VCONTROL MAX = 3.7 V VCONTROL These re−activations of “Flag1” result from VOUT 100 or 120 Hz ripple (not represented here for the sake of clarity) Flag1 Circuit State OFF pfcOK Drive Output Figure 70. Startup Phase in Normal Conditions http://onsemi.com 29 NCP1605 The Circuit is Off ≥ Low Consumption VCCON VCCOFF VCC VCCSTUP 1V Vout Regulation Level VOUT 1V 0.5 V Brown−Out Pin Voltage Drive Output Circuit State OFF pfcOK Figure 71. Startup and Brown Out Conditions When the high voltage, startup current source is on, the brown−out is active and its threshold is the upper one (VBO = VBOH = 1 V). Fault Management Block When any of the following faults is detected: brown−out (“BO_NOK”), Undervoltage (“UVP”), shutdown (“STDWN”), Die Overtemperature (“TSD”), the circuit immediately turns off and recovers operation as soon as the fault disappears. In case of UVLO (VCC too low to allow operation), the circuit keeps off until the end of the next VCC charge phase by the HV startup current source. The following block diagram details the function. Internal Thermal Shutdown UVP TSD BO_NOK Stdwn UVLO (Vcc<VccOFF) S Q UVLO Latch R HVCS_ON Figure 72. Fault Management Block http://onsemi.com 30 OFF NCP1605 Bulk BOon BOoff Single Hiccup VCC VCCon Internal BOok VCCoff Drive Figure 73. The above figure shows how the circuit recovers after a brown−out event. http://onsemi.com 31 NCP1605 PACKAGE DIMENSIONS SOIC−16 D SUFFIX CASE 751B−05 ISSUE K NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: MILLIMETER. 3. DIMENSIONS A AND B DO NOT INCLUDE MOLD PROTRUSION. 4. MAXIMUM MOLD PROTRUSION 0.15 (0.006) PER SIDE. 5. DIMENSION D DOES NOT INCLUDE DAMBAR PROTRUSION. ALLOWABLE DAMBAR PROTRUSION SHALL BE 0.127 (0.005) TOTAL IN EXCESS OF THE D DIMENSION AT MAXIMUM MATERIAL CONDITION. −A− 16 9 −B− P 1 8 PL 0.25 (0.010) 8 B M S DIM A B C D F G J K M P R G R K F X 45 _ C −T− SEATING PLANE J M D 16 PL 0.25 (0.010) M T B S A MILLIMETERS MIN MAX 9.80 10.00 3.80 4.00 1.35 1.75 0.35 0.49 0.40 1.25 1.27 BSC 0.19 0.25 0.10 0.25 0_ 7_ 5.80 6.20 0.25 0.50 INCHES MIN MAX 0.386 0.393 0.150 0.157 0.054 0.068 0.014 0.019 0.016 0.049 0.050 BSC 0.008 0.009 0.004 0.009 0_ 7_ 0.229 0.244 0.010 0.019 S SOLDERING FOOTPRINT* 8X 6.40 16X 1 1.12 16 16X 0.58 1.27 PITCH 8 9 DIMENSIONS: MILLIMETERS *For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. Soft−Skip is a trademark of Semiconductor Components Industries, LLC (SCILLC). The products described herein, may be covered by the following U.S. patents: 5,502,370 6,271,735, 6,362,067, 6,970,365. There may be other patents pending ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. 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