SLVA372D November   2009  – November 2022 LM2577 , LM2585 , LM2586 , LM2587 , LM2588 , LMR61428 , LMR62014 , LMR62421 , LMR64010 , TL1451A , TL5001 , TL5001A , TLV61220 , TPS40210 , TPS40211 , TPS43000 , TPS61000 , TPS61002 , TPS61005 , TPS61006 , TPS61007 , TPS61010 , TPS61012 , TPS61013 , TPS61014 , TPS61015 , TPS61016 , TPS61020 , TPS61021A , TPS61024 , TPS61025 , TPS61026 , TPS61027 , TPS61028 , TPS61029 , TPS61029-Q1 , TPS61030 , TPS61031 , TPS61032 , TPS61046 , TPS61070 , TPS61071 , TPS61072 , TPS61073 , TPS61085 , TPS61086 , TPS61087 , TPS61089 , TPS61090 , TPS61091 , TPS61092 , TPS61093 , TPS61093-Q1 , TPS61097-33 , TPS61100 , TPS61107 , TPS61120 , TPS61121 , TPS61122 , TPS61130 , TPS61131 , TPS61170 , TPS61175 , TPS61175-Q1 , TPS61200 , TPS61201 , TPS61202 , TPS61220 , TPS61221 , TPS61222 , TPS61230A , TPS61235P , TPS61236P , TPS61240 , TPS61241 , TPS61253 , TPS61254 , TPS61256 , TPS61258 , TPS61259 , TPS612592 , TPS61291 , TPS65070 , TPS65072 , TPS65073 , TPS65100 , TPS65100-Q1 , TPS65101 , TPS65105 , TPS65130 , TPS65131 , TPS65131-Q1 , TPS65132 , TPS65132S , TPS65133 , TPS65137 , TPS65140 , TPS65140-Q1 , TPS65141 , TPS65142 , TPS65145 , TPS65145-Q1 , TPS65150 , TPS65150-Q1 , TPS65154 , TPS65155 , TPS65160 , TPS65160A , TPS65161 , TPS65161A , TPS65161B , TPS65162 , TPS65163 , TPS65167A , TPS65170 , TPS65175 , TPS65175B , TPS65175C , TPS65176 , TPS65177 , TPS65177A , TPS65178 , TPS65631 , TPS65631W , TPS65632 , TPS65632A , TPS65640 , TPS65642 , TPS65642A , UCC39411

 

  1.   Basic Calculation of a Boost Converter's Power Stage
  2. 1 Basic Configuration of a Boost Converter
    1. 1.1 Necessary Parameters of the Power Stage
  3. 2 Calculate the Maximum Switch Current
  4. 3 Inductor Selection
  5. 4 Rectifier Diode Selection
  6. 5 Output Voltage Setting
  7. 6 Input Capacitor Selection
  8. 7 Output Capacitor Selection
  9. 8 Equations to Calculate the Power Stage of a Boost Converter
  10. 9 References
  11. 10Revision History

8 Equations to Calculate the Power Stage of a Boost Converter

Equation 14. GUID-E5175946-DD3B-4709-B10C-94A169004185-low.gif

VIN(min) = minimum input voltage
VOUT = desired output voltage
η = efficiency of the converter, e.g. estimated 85%

Equation 15. GUID-63AEFCB6-9E30-4B7F-99D9-BFBC62F6B84F-low.gif

VIN(min) = minimum input voltage
D = duty cycle calculated in Equation 14
fS = minimum switching frequency of the converter
L = selected inductor value

Equation 16. GUID-FB375935-D084-4D04-B705-68A11889AC44-low.gif

ILIM(min) = minimum value of the current limit of the integrated witch (given in the data sheet)
ΔIL = inductor ripple current calculated in Equation 15
D = duty cycle calculated in Equation 14

Equation 17. GUID-FF0619EF-D851-4DD2-84A7-83B4485F1E73-low.gif

ΔIL = inductor ripple current calculated in Equation 15
IOUT(max) = maximum output current necessary in the application
D = duty cycle calculated in Equation 14

Equation 18. GUID-FD7FB7AC-35C3-474E-AACF-BF71F0667D26-low.gif

VIN = typical input voltage
VOUT = desired output voltage
fS = minimum switching frequency of the converter
ΔIL= estimated inductor ripple current, see Equation 19

Equation 19. GUID-B1BFC618-AABB-4362-803F-4DDA244CD0DB-low.gif

ΔIL = estimated inductor ripple current
IOUT(max) = maximum output current necessary in the application

Equation 20. GUID-D7C39E59-2ADB-4AA0-BEA3-23E7DCDAA4EF-low.gif

IOUT(max) = maximum output current necessary in the application

Equation 21. GUID-0EC7D45D-F04A-4894-B574-EB618031D98B-low.gif

IF = average forward current of the rectifier diode
VF = forward voltage of the rectifier diode

Equation 22. GUID-176BBE65-249B-4B3C-8D0D-587015546D81-low.gif

IFB = feedback bias current from data sheet

Equation 23. GUID-701B36EA-DE03-4EB5-8895-F0263F577D42-low.gif
Equation 24. GUID-26686A42-1220-4116-8325-BCE16B935430-low.gif

VFB = feedback voltage from the data sheet
IR1/2 = current through the resistive divider to GND, calculated in Equation 22
VOUT = desired output voltage

Equation 25. GUID-2FB7A449-FB74-4D37-8DC8-F6F2845BCFFD-low.gif

IOUT(max) = maximum output current of the application
D = duty cycle calculated in Equation 14
fS = minimum switching frequency of the converter
ΔVOUT = desired output voltage ripple

Equation 26. GUID-4F80D4F9-9E85-4335-AE2E-554D9C3F9EDD-low.gif

ESR = equivalent series resistance of the used output capacitor
IOUT(max) = maximum output current of the application
D = duty cycle calculated in Equation 14
ΔIL = inductor ripple current from Equation 15 or Equation 19