Power Supply Design - PFC Loops

             
Input data Vinm= 176 Vrms Minimum AC Input Voltage    
  Vinn= 230 Vrms Nominal AC Input Voltage    
  Vinx= 276 Vrms Maximum AC Input Voltage    
  fpfc= 140 kHz PFC switching frequency    
  fline= 50 Hz Line Frequency    
  Ppfc= 2,689 W Maximum Output Power, PFC Stage    
  Cb= 1,269 uF Boost Capacitor, chosen    
  Vba= 407 V Average boost voltage    
  Vbpp= 16.6 Vpp Boost Voltage ripple, peak to peak    
  Lb= 83.0 uH PFC boost inductor    
  Iinx= 16.0 Arms Maximum rms Input Current @ low line    
  Iinn= 12.2 Arms Nominal rms Input Current @ nominal line    
  Ibpkx= 26.8 Apk Boost Ind., Switch and Diode max pk current    
  Vspfc= 270 mV Peak voltage, PFC shunt, nominal conditions    
  Iacpkx= 300 uA Maximum peak Iac @ Maximum line    
  Vs= 5.4 Vpp Slope voltage, peak to peak 5.4  
  Vvea= 3.5 Vpp Vvea=1.5V to 5V. At 5V full power.    
  V3thd= 4.0 % Third harmonic contribution to THD    
  V3vff= 1.6 % Third harmonic contribution to THD due to Vff    
  V3vao= 2.4 % Third harmonic contribution to THD due to Vvao Vvao rip=2x1.5%  
  Rvi= 962 k      
  Rff1= 960 k      
  Rff2= 100 k      
  Rff3= 20 k      
  Rpk1= 10 k      
  Ilim= 30 % Percentage above nominal    
  Plim= 20 % Input power percentage above nominal    
             
Output data Rspfcc= 15.6 mOhm PFC shunt resistor    
  Rspfc= 15.0 mOhm PFC shunt resistor, chosen    
  Pspfc= 2.2 W PFC shunt, nominal power    
  Pspfc= 3.8 W PFC shunt, maximum power    
  Rvacc= 1,301 k Multiplier Iac set resistor    
  Rvac= 1,298 k Multiplier Iac set resistor, chosen    
  Iacl= 192 uA Iac at low line    
  Iml= 384 uA Multiplier current limit at low line. Should be > 78  
  Impk= 78 uA Multiplier current at peak low line    
  Vffm= 2.93 V Multiplier Vrms input at low line    
  Vffn= 3.83 V Multiplier Vrms input at nominal line    
  Vffx= 4.60 V Multiplier Vrms input at high line    
  Gff= 0.024        
  fp= 16 Hz Vff double pole frequency    
  Cff1= 102 nF      
  Cff2= 512 nF      
  Vspfcx= 339 mV Peak voltage, PFC shunt, low line    
  Rmoc= 3.63 k Resistor, multiplier output    
  Rmo= 3.74 k Resistor, multiplier output, chosen    
  dVs/dt 0.756 V/us Timing capacitor voltage slope    
  dVspfc/dt= 0.074 V/us Shunt voltage downslope    
  Gca= 10.28   Gain, current amplifier    
  Rci=Rmo= 3.74 k      
  Rcz= 38.4 k      
  fci= 22.3 kHz Current loop crossover frequency, should be = 22.3  
  Cczp= 588 pF      
  Ccz= 560 pF      
  Ccpc= 59 pF      
  Ccp= 56 pF      
  Gva= 0.0203        
  Cvf= 81.6 nF      
  fvi= 21.9 Hz      
  Rvf= 89.0 k      
  Rpk2= 0.697 k      
  Rvd= 6.84 k      
             
             
The reference designators are those used by Unitrode in its application notes.    
             
             
             
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Comments and suggestions are welcomed. See the full spreadsheet at: ADH2450Deszg.xls

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Copyright © 1998-2005 SMPS Power Supplies Inc. All rights reserved.