ViperPlus Series for DCDC

[Clover1220]

I am trying to build a DCDC Converter with following conditions

Vin: 400~600VDC

Vout: 12~15VDC

(Isolation is not required)

Current Rating: 100mA~300mA(Not really stricted)

I can see DC application simple schematic at the first page of the datasheet for ViperPlus Family.

However, every examples are AC Inputs with Full bridge Rectifiers.

May I just skip the rectifiers use it for DC Application?

I guess L,C are for noise filtering.

All application notes are for AC DC Converter.

[Peter BENSCH · Accepted solution]

Welcome @Clover1220, to the community!

Your assumption is correct, you can use the VIPerPLUS as a DCDC converter (btw: correctly considered, only the rectifier is an ACDC converter, followed by the DCDC). For your voltage range you should not consider the VIPerPLUS*2 as they only priovide a 730V switch. The other VIPerPLUS have at least an 800V switch, which should be sufficient for your buck, the VIPer26K even has a 1050V switch.

However, you should not forget that the VIPerPLUS data is specified for flyback regulators; when used as a buck regulator, the stable output power that can be achieved decreases as the voltage difference increases, as I have already explained e.g. here, there and there. However, you can recalculate your input voltage to an AC voltage (i.e. division by sqrt(2) for the usual bridge rectifier) and simulate with this value using the

• eDesignSuite > AC/DC > Start a new project

You should pay particular attention to power loss and phase margin. In the worst case, you convert 600V to 12V, i.e. to 2% of the input voltage, which results in extremely short switch-on pulses that are difficult to control.

It would actually be easiest if you realised a flyback that can also be galvanically connected, i.e. without an optocoupler, because this makes the design much easier and more stable to realise.

Hope that helps?

Regards
/Peter

[Clover1220]

Thanks for your help,

I will bring back results when I successfully build it and test it