Switching Power Supplies A - Z

The Principles of Switching Power Conversion

the board. Therefore, the buck-boost may also demand much better filtering at its

input, and often at its output too.

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Though current enters the output capacitor to charge it up when the switch turns ON,

and leaves it to go into the load when the switch is OFF, the average capacitor

current is always zero. In fact, any capacitor in ‘steady state’ must, by definition,

have zero average current passing through it — otherwise it would keep charging or

discharging until it too reaches a steady state, just like the inductor current.

Since the average current from the output capacitor is zero, therefore, for the ...