LMR16020: How to calculate the input capacitor of LMR16020?

user4828678

Prodigy 20 points

Part Number: LMR16020

For the spec, I know the formula that how to calculate the input capacitor,

Cmin = Iout *dc (1-dc)/(Fsw*Vp)

but i dont know the detailed process,

can u help me to explain the formula,thanks!

over 8 years ago

0 Vental Mao over 8 years ago

TI__Expert 5745 points

I think you can refer to the book<Switching Power Supplies A-Z,2E>.In the Section 13.1, you can get the detail what you want.

0 JohnTucker over 8 years ago in reply to Vental Mao

TI__Guru**** 191445 points

That equation selects the capacitor value based on the allowable input voltage ripple that is impressed back on the input voltage bus by the converter. You supply the output current, switching frequency and duty cycle for your design (dc = Vout/Vin) as well as the amuout of ripple volte you can tolerate to calculate Cin value,

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LMR16020: How to calculate the input capacitor of LMR16020?