AN4121 | DigiCamel IC Datasheet

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AN4121 FAIRCHILD | Alldatasheet

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voltage. The non-inverting input is internally biased at 2.5V . the multiplier and is pinned out for the loop compensation. reducing the input current drawn from the mains(soft OVP). the output stage and the external power switch turned off. goes back into its linear region. output under all line and load conditions. pre-converter load appear to be resistive to the ac line. multiplier output and its inputs. Figure 3. Error Amplifier and OVP Block

connecting it to the zero current detector Pin 5. 150us after the inductor current reached zero. Figure 6. Zero Current Detector Block designed specifically for a direct drive of power MOSFET. required for the reliable circuit operation.

Circuit Components Design

frequency has to be above the audio frequency.

The auxiliary winding voltage is lowest at the highest line. So the number of auxiliary winding can be obtained by (7). input displacement factor(IDF), defined as IDF ≡cosθ . Figure 7. Input Current and Inductor Current Waveform during a Switching Cycle

©2002 Fairchild Semiconductor Corporation The value is calculated on the assumption that the gate-source voltage should be a square waveform, i.e, abrupt changes with no rising or falling time. Thus the drive current can not reach 500mA during the rising or falling time although Rg of 32Ω is used. 10Ω is recommended as the Rg in order to the MOSFET switching loss. The experimental results shows that the gate peak current goes up to 300mA with 10Ω . Diode average current can be calculated by (21). The total diode loss can be calculated by (22) and then a diode can be selected considering diode thermal characteristic. 3-2. Control circuit design 1) Output voltage sensing resistor and feedback loop design R 1 is determined by the maximum output over voltage, ∆Vovp and R2 is determined by (23). The feedback loop bandwidth must be narrower than 20Hz for the PFC application. Therefore a capacitor is connected between INV and EA_OUT to eliminate the 120Hz ripple voltage by 40dB. The error amp compensation capacitor can be calculated by (24). To improve the power factor, C comp must be increased than the calculated value. And to improve the system response, C comp must be lowered than the calculated value. 2) Zero current detection resistor design Idet current should be less than 3mA, therefore zero current detection resistor is determined by (25). 3) Start-up circuit design To start-up the FAN7527B, the start-up current must be supplied through a start-up resistor. The resistor value is calculated by (26) and (27). The start-up capacitor must supply IC operating current before the auxiliary winding supplies IC operating current maintaining Vcc voltage higher than the UVLO voltage. Therefore the start-up capacitor is designed by (28). The recommended R ST values according to C ST values are shown on table 1. To make the Vcc voltage stable, use R ST values listed on the table or lower R ST values than the listed values. Higher R ST values can cause the system unstable, therefore don't use higher RST values. 4) Line voltage sense resistor and current sense resistor design The maximum line voltage sensing gain is determined by (29) at the highest line. Calculate the pin 3 voltage at the lowest line using G in(max) by (30). Then the current sense resistor is determined by (31), (32) and (34). Once the current sense resistor is determined, then the minimum line voltage sensing gain, G in(max) is determined by (31). Rg VOmax IOmax IDavg IOm a x()=2 1 () PDiode VfIDavg=2 2 () VO 2.5– ∆ VOVP 2.5R1 Ccomp Ridet Naux VO⋅ Table 1: Recommended RST , CST values CST RST 22uF 100k Ω 33uF 120k Ω 47uF 120k Ω 68uF 120k Ω RST Vin peak_min() Vth st() max– ISTmax PRst in rms_max() RST CST Idcc VPIN3 Vin peak_max() Rin2 Vin peak_max() Gin max() 3.8V<⋅= 29() VOm() KV in peak_min() Rin2 Rse nse VOm() ILp e a k _ m a x() Rin2 2.5⋅ V η Vin peak_min() Rsense 1.8V ILp e a k _ m a x() η Vin peak_min() PRsense 2 VOIOm a x() η Vin peak_min()  2 Rsense⋅⋅= 1W< 33() Rsense η Vin peak_min() VOIOm a x()  2 ⋅< 34()

©2002 Fairchild Semiconductor Corporation And attach 1nF capacitor in parallel with R2 to reduce the switching ripple voltage. 4. Design Example A 100W converter is designed to illustrate the design proce- dure. The system parameters are as follows.

Maximum output power : 100W
Input voltage range : 85Vrms~265Vrms
Output voltage : 400V
AC line frequency : 60Hz
PFC efficiency : 90%
Minimum switching frequency : 33kHz
Input displacement factor(IDF) : 0.97
Input capacitor ripple voltage : 24V
Output voltage ripple : 8V
OVP set voltage : 440V 4-1. Inductor design The boost inductor is determined by (6). Calculate it at both the lowest line and the highest line and choose the lower value. The calculated value is 604uH. To get the calculate inductor value, EI3026 core is used and the primary winding is 58 turns. The air gap is 0.80mm at both legs of the EI core. The auxiliary winding is determined by (7) and the auxiliary winding is 4 turns. 4-2. Input capacitor design The minimum input capacitance is determined by the input voltage ripple specification. The calculated minimum input capacitor value is 0.58uF. And the maximum input capacitance is restricted by IDF. The calculated value is 0.94uF. The selected value is 0.88uF for the input capacitors (sum of all capacitors connected to the input). 4-3. Output capacitor design The minimum output capacitor is determined by (14) and the calculated value is 83uF. The selected value is 100uF capacitor. 4-4. MOSFET and diode selection By (15)~(19), 500V/4.6A MOSFET IRFS840B is selected and by (21)~(23), and 600V/1A diode BYV26C is selected by (21)~(22). 4-5. Output voltage sense resistor and feedback loop design The upper output voltage sense resistor is 1.0MΩ and the bottom output voltage sense resistor is 6kΩ plus 10kΩ variable resistor. A variable resistor is used to adjust the output voltage. To improve the power factor, the error amp compensation capacitance must be larger than 0.132uF by (24). Therefore 1uF capacitor is used. 4-6. Zero current detection resistor design The calculate value is 430Ω and the selected value is 22kΩ . 4-7. Start-up circuit design The maximum start-up resistor is 1 MΩ and the minimum is 70kΩ by (26)~(27). Our selection is 120kΩ . And the start-up capacitance must be larger than 10.6uF by (28). The selected value is 47uF. 4-8. Line voltage sense resistor and current sense resistor design The maximum input voltage sensing gain is determined by (29). Using the calculated value, the current sense resistance is determined by (31), (32) and (34). The maximum current sense resistance is 0.48 Ω and the selected value is 0.4 Ω . Then the minimum input voltage sensing gain is determined by (30). If we choose the input voltage sense bottom resistor to be 22k Ω then the maximum input voltage sense upper resistance and the minimum input voltage sense upper resistance can be obtained from G in(min) and Gin(max) . The selected value is 1.8MΩ . Fig. 11 shows the designed application circuit diagram and table 2~11 show the application circuit components lists of 32W, 64W, 100W, 150W and 200W application.

Figure 11. Application circuit diagram

©2002 Fairchild Semiconductor Corporation Table 2: FAN7527B 32W Wide-Range Application Circuit Components list Part Number Value Note Manufacturer R1 1.8M Ω 1/4W - R2 22k Ω 1/4W - R3 120k Ω 1W - R5 22k Ω 1/4W - R6 10 Ω 1/4W - R7 1.33 Ω 1W - R8 1M Ω 1/4W - R9 6k Ω 1/4W - VR1 103 Variable resistor - C1 47nF, 275vac Box-Cap - C2 100nF, 275vac Box-Cap - C3, 4 2200pF, 3000V Y-Cap - C5 0.1 µF, 630V Miller-Cap - C6 47 µF, 35V Electrolytic - C7 1 µFM L C C - C8 22 µF, 450V Electrolytic - C9 1nF, 25V Ceramic - BD1 600V/4A Bridge Diode - D1, 3 75V, 150mA 1N4148 - D2 600V, 1A BYV26C - LF1 45mH Line Filter - T1 1.84mH(140T:11T) EI2519 - Q1 500V, 2.3A FQPF4N50 Fairchild F1 250V, 3A Fuse - V1 470V 471 - NTC 10 Ω 10D09 -

©2002 Fairchild Semiconductor Corporation Table 3: FAN7527B 32W 220Vac Application Circuit Components list Part Number Value Note Manufacturer R1 1.8M Ω 1/4W - R2 18k Ω 1/4W - R3 120k Ω 1W - R5 22k Ω 1/4W - R6 10 Ω 1/4W - R7 3.0 Ω 1W - R8 1M Ω 1/4W - R9 6k Ω 1/4W - VR1 103 Variable resistor - C1 47nF, 275vac Box-Cap - C2 100nF, 275vac Box-Cap - C3, 4 2200pF, 3000V Y-Cap - C5 0.1 µF, 630V Miller-Cap - C6 47 µF, 35V Electrolytic - C7 1 µFM L C C - C8 22 µF, 450V Electrolytic - C9 1nF, 25V Ceramic - BD1 600V/4A Bridge Diode - D1, 3 75V, 150mA 1N4148 - D2 600V, 1A BYV26C - LF1 45mH Line Filter - T1 1.76mH(122T:10T) EI2219 - Q1 500V, 2.3A FQPF4N50 Fairchild F1 250V, 3A Fuse - V1 470V 471 - NTC 10 Ω 10D09 -

©2002 Fairchild Semiconductor Corporation Table 4: FAN7527B 64W Wide-Range Application Circuit Components list Part Number Value Note Manufacturer R1 1.8M Ω 1/4W - R2 22k Ω 1/4W - R3 120k Ω 1W - R5 22k Ω 1/4W - R6 10 Ω 1/4W - R7 0.68 Ω 1W - R8 1M Ω 1/4W - R9 6k Ω 1/4W - VR1 103 Variable resistor - C1 47nF, 275vac Box-Cap - C2 150nF, 275vac Box-Cap - C3, 4 2200pF, 3000V Y-Cap - C5 0.33 µF, 630V Miller-Cap - C6 47 µF, 35V Electrolytic - C7 1 µFM L C C - C8 68 µF, 450V Electrolytic - C9 1nF, 25V Ceramic - BD1 600V/4A Bridge Diode - D1, 3 75V, 150mA 1N4148 - D2 600V, 1A BYV26C - LF1 45mH Line Filter - T1 0.9mH(80T:6T) EI2820 - Q1 500V, 3.1A IRFS830B Fairchild F1 250V, 3A Fuse - V1 470V 471 - NTC 10 Ω 10D09 -

©2002 Fairchild Semiconductor Corporation Table 5: FAN7527B 64W 220Vac Application Circuit Components List Part Number Value Note Manufacturer R1 1.8M Ω 1/4W - R2 18k Ω 1/4W - R3 120k Ω 1W - R5 22k Ω 1/4W - R6 10 Ω 1/4W - R7 1.5 Ω 1W - R8 1M Ω 1/4W - R9 6k Ω 1/4W - VR1 103 Variable resistor - C1 47nF, 275vac Box-Cap - C2 150nF, 275vac Box-Cap - C3, 4 2200pF, 3000V Y-Cap - C5 0.22 µF, 630V Miller-Cap - C6 47 µF, 35V Electrolytic - C7 1 µFM L C C - C8 68 µF, 450V Electrolytic - C9 1nF, 25V Ceramic - BD1 600V/4A Bridge Diode - D1, 3 75V, 150mA 1N4148 - D2 600V, 1A BYV26C - LF1 45mH Line Filter - T1 1.1mH(90T:7T) EI2820 - Q1 500V, 3.1A IRFS830B Fairchild F1 250V, 3A Fuse - V1 470V 471 - NTC 10 Ω 10D09 -

©2002 Fairchild Semiconductor Corporation Table 6: FAN7527B 100W Wide-Range Application Circuit Components List Part Number Value Note Manufacturer R1 1.8M Ω 1/4W - R2 22k Ω 1/4W - R3 120k Ω 1W - R5 22k Ω 1/4W - R6 10 Ω 1/4W - R7 0.4 Ω 1W - R8 1M Ω 1/4W - R9 6k Ω 1/4W - VR1 103 Variable resistor - C1 47nF, 275vac Box-Cap - C2 150nF, 275vac Box-Cap - C3, 4 2200pF, 3000V Y-Cap - C5 0.68 µF, 630V Miller-Cap - C6 47 µF, 35V Electrolytic - C7 1 µFM L C C - C8 100 µF, 450V Electrolytic - C9 1nF, 25V Ceramic - BD1 600V/4A Bridge Diode - D1, 3 75V, 150mA 1N4148 - D2 600V, 1A BYV26C - LF1 45mH Line Filter - T1 0.6mH(58T:4T) EI3026 - Q1 500V, 4.6A IRFS840B Fairchild F1 250V, 3A Fuse - V1 470V 471 - NTC 10 Ω 10D09 -

©2002 Fairchild Semiconductor Corporation Table 7: FAN7527B 100W 220Vac Application Circuit Components List Part Number Value Note Manufacturer R1 1.8M Ω 1/4W - R2 18k Ω 1/4W - R3 120k Ω 1W - R5 22k Ω 1/4W - R6 10 Ω 1/4W - R7 0.8 Ω 1W - R8 1M Ω 1/4W - R9 6k Ω 1/4W - VR1 103 Variable resistor - C1 47nF, 275vac Box-Cap - C2 150nF, 275vac Box-Cap - C3, 4 2200pF, 3000V Y-Cap - C5 0.47 µF, 630V Miller-Cap - C6 47 µF, 35V Electrolytic - C7 1 µFM L C C - C8 100 µF, 450V Electrolytic - C9 1nF, 25V Ceramic - BD1 600V/4A Bridge Diode - D1, 3 75V, 150mA 1N4148 - D2 600V, 1A BYV26C - LF1 45mH Line Filter - T1 0.8mH(75T:5T) EI2820 - Q1 500V, 4.6A IRFS840B Fairchild F1 250V, 3A Fuse - V1 470V 471 - NTC 10 Ω 10D09 -

©2002 Fairchild Semiconductor Corporation Table 8: FAN7527B 150W Wide-Range Application Circuit Components List Part Number Value Note Manufacturer R1 1.8M Ω 1/4W - R2 22k Ω 1/4W - R3 120k Ω 1W - R5 22k Ω 1/4W - R6 10 Ω 1/4W - R7 0.25 Ω 1W - R8 1M Ω 1/4W - R9 6k Ω 1/4W - VR1 103 Variable resistor - C1 330nF, 275vac Box-Cap - C2 330nF, 275vac Box-Cap - C3, 4 2200pF, 3000V Y-Cap - C5 1 µF, 630V Miller-Cap - C6 47 µF, 35V Electrolytic - C7 1 µFM L C C - C8 150 µF, 450V Electrolytic - C9 1nF, 25V Ceramic - BD1 600V/6A Bridge Diode - D1, 3 75V, 150mA 1N4148 - D2 600V, 1.5A SUF15J - LF1 45mH Line Filter - T1 0.495mH(54T:4T) EI4035 - Q1 500V, 13.4A FQA13N50 Fairchild F1 250V, 3A Fuse - V1 470V 471 - NTC 10 Ω 10D09 -

©2002 Fairchild Semiconductor Corporation Table 9: FAN7527B 150W 220Vac Application Circuit Components List Part Number Value Note Manufacturer R1 1.8M Ω 1/4W - R2 22k Ω 1/4W - R3 120k Ω 1W - R5 22k Ω 1/4W - R6 10 Ω 1/4W - R7 0.5 Ω 1W - R8 1M Ω 1/4W - R9 6k Ω 1/4W - VR1 103 Variable resistor - C1 330nF, 275vac Box-Cap - C2 330nF, 275vac Box-Cap - C3, 4 2200pF, 3000V Y-Cap - C5 1 µF, 630V Miller-Cap - C6 47 µF, 35V Electrolytic - C7 1 µFM L C C - C8 150 µF, 450V Electrolytic - C9 1nF, 25V Ceramic - BD1 600V/6A Bridge Diode - D1, 3 75V, 150mA 1N4148 - D2 600V, 1A BYV26C - LF1 45mH Line Filter - T1 0.56mH(46T:3T) EI3026 - Q1 500V, 5.3A FQPF9N50 Fairchild F1 250V, 3A Fuse - V1 470V 471 - NTC 10 Ω 10D09 -

©2002 Fairchild Semiconductor Corporation Table 10: FAN7527B 200W Wide-Range Application Circuit Components List Part Number Value Note Manufacturer R1 2.2M Ω 1/4W - R2 27k Ω 1/4W - R3 120k Ω 1W - R5 22k Ω 1/4W - R6 10 Ω 1/4W - R7 0.15 Ω 1W - R8 1M Ω 1/4W - R9 6k Ω 1/4W - VR1 103 Variable resistor - C1 330nF, 275vac Box-Cap - C2 330nF, 275vac Box-Cap - C3, 4 2200pF, 3000V Y-Cap - C5 1 µF, 630V Miller-Cap - C6 47 µF, 35V Electrolytic - C7 1 µFM L C C - C8 220 µF, 450V Electrolytic - C9 1nF, 25V Ceramic - BD1 600V/6A Bridge Diode - D1, 3 75V, 150mA 1N4148 - D2 600V, 1.5A SUF15J - LF1 45mH Line Filter - T1 0.4mH(76T:5T) CM330060(troidal core) ChangSung Q1 500V, 13.4A FQA13N50 Fairchild F1 250V, 3A Fuse - V1 470V 471 - NTC 10 Ω 10D09 -

©2002 Fairchild Semiconductor Corporation Table 11: FAN7527B 200W 220Vac Application Circuit Components List Part Number Value Note Manufacturer R1 2.2M Ω 1/4W - R2 22k Ω 1/4W - R3 120k Ω 1W - R5 22k Ω 1/4W - R6 10 Ω 1/4W - R7 0.4 Ω 1W - R8 1M Ω 1/4W - R9 6k Ω 1/4W - VR1 103 Variable resistor - C1 330nF, 275vac Box-Cap - C2 330nF, 275vac Box-Cap - C3, 4 2200pF, 3000V Y-Cap - C5 1 µF, 630V Miller-Cap - C6 47 µF, 35V Electrolytic - C7 1 µFM L C C - C8 220 µF, 450V Electrolytic - C9 1nF, 25V Ceramic - BD1 600V/6A Bridge Diode - D1, 3 75V, 150mA 1N4148 - D2 600V, 1.5A SUF15J - LF1 45mH Line Filter - T1 0.4mH(52T:4T) EI3530 - Q1 500V, 13.4A FQA13N50 Fairchild F1 250V, 3A Fuse - V1 470V 471 - NTC 10 Ω 10D09 -

©2002 Fairchild Semiconductor Corporation Nomenclature IL(peak) (t) : inductor current peak value during one switching cycle IL(peak) : inductor current peak value during one AC line cycle IL(peak_max) : maximum inductor current peak value IL (t) : inductor current ID : boost diode current Iin (t) : input current Iin (peak) : input current peak value Iin (peak_max) : maximum of the input current peak value Iin (rms) : input current RMS value IQrms : MOSFET rms current IDrms : diode rms current IDavg : diode average current IO : output current IO (max) : maximum output current Vin (t) : input voltage ∆Vin (max) : maximum input voltage ripple Vin (peak) : input voltage peak value Vin (peak_max) : maximum input voltage peak value Vin (peak_min) : minimum input voltage peak value Vin (rms) : input voltage RMS value Vin (rms_max) : maximum input voltage RMS value Vin (rms_min) : minimum input voltage RMS value Vin (LL) : low line rms input voltage Vin (HL) : high line rms input voltage VO : output voltage ∆VO (max) : maximum output voltage ripple ∆VOVP : maximum output over voltage PO : output power PO(max) : maximum output power Pin : input power η : converter efficiency ton : switch on time toff : switch off time tf : MOSFET current falling time TS : switching period fac : AC line frequency ω : AC line angular frequency fSW : switching frequency fSW(max) : maximum switching frequency fSW(min) : minimum switching frequency L : boost inductance CO : output capacitance Cin : input capacitance η : converter efficiency Naux : auxiliary winding turn number NP : boost inductor turn number Ccomp : compensation capacitance Ridet : zero current detection resistance RST : start-up resistance R1 : output voltage divider top resistance R2 : output voltage divider bottom resistance Rin1 : input voltage divider top resistance Rin2 : input voltage divider bottom resistance Rsense : current sense resistance ISTmax : maximum start-up supply current CST : start-up capacitance HY(ST)min : minimum UVLO hysteresis K : multiplier gain Gin (min) : minimum input voltage sense gain Gin (max) : maximum input voltage sense gain

5/30/02 0.0m 002 Stock#ANxxxxxxxxx  2002 Fairchild Semiconductor Corporation DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPROATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, or (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in significant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. www.fairchildsemi.com

Product Information

AN4121 specifications and overview.

Summary

Design of Power Factor Correction Circuit

Description

Design of Power Factor Correction Circuit

Source title AN4121 Datasheet(PDF) - Fairchild Semiconductor

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