Cap chargers

Yandersen, Sat Sept 26 2015, 07:11PM

Why there is no thread for power converters in this forum? Let's make one and post some schematics!

Here is a simple 12V -> 400V flyback DC-DC converter operating in continuous mode and capable of delivering up to 100W of output power to the capacitive load:


]flyback_100w.zip[/file]



This charger has simple design, can withstand a short-circuit at output and requires no radiators. The output diode should be a single C4D02120A, but I simply do not have this model in my LTSpice database.

The charger's logic is simple: the transformer sucks current (up to 19 Amps) from the supply for an amount of time defined by Rt-Ct (13 us), then it discharges to the output capacitor until the current ceases from 1.2A to a low limit (0.65A) defined by Risense, then the charge cycle starts again and so on until the desired voltage (380V) is reached (defined by resistor divider Rdiv1-Rdiv2).

P.S.: Rload is not a part of the charger, of course. It is here just to show where the output load should be connected. And the load is a cap bank, actually, not necessarily a resistive load.