Use transformer with bridge rectifier as input for SZBK07

[rowan.bradley]

I have bought a SZBK07 buck regulator to use as a constant current power supply for electroplating. Does anyone know whether I can just use a transformer with a bridge rectifier as the input for this converter, or whether the ripple will prevent it working properly? In which case presumably I need at least a large reservoir capacitor, or a more sophisticated PSU.

Thank you - Rowan

 

[cupoftea]

You can use Txfmr/rect plus big smoothing cap if you want.....but make sure the vin would be sufficient over the variation range of your mains...eg 180-265VAC for example....if vac drops, then your TRU output drops...and if it goes below the level of the required vout, then youre toasted.
Also, have enough cap so that at the "troughs" (every 10ms), the vin doesnt fall too low (for same reason).

Also, beware, since if mains swells up to 300vac say (confessedly unlikely) then your rectified vin could go so high that it pops the SZB.

The attached is a sim for you in the free LTspice simulator....if you wish you can adjust it to have your esr and turns ration