UCC28221: UCC28221

Junia George

Part Number: UCC28221
Other Parts Discussed in Thread: UCC27324

i want to know whether a forward converter will work even without a diode in series with the tertiary winding of the transformer.

The evaluation module of UCC28221 , the diode is not kept.

0 John Griffin1 over 4 years ago

Hello,

Can you provide more details to your question ?

An evaluation module is not available for the UCC28221

Regards

John

0 Junia George over 4 years ago in reply to John Griffin1

Sure sir.

please check the below attachment for evaluation module user guide.

In that there is no tertiary winding with diode in series or a snubber for demagnetization of the transformer when switch(MOSFET) is turned OFF.

can you explain why?

0 John Griffin1 over 4 years ago in reply to Junia George

Hello,

I think you refer to the bias winding of the main transformer T4 as the tertiary winding.

IN fact this bias winding has an output labelled A and A is rectified with D1 as shown in the left hand side of the schematic.

This generates VDD which is the bias power for the UCC28221 and the UCC27324.

To start up the UCC28221, the VIN pin is connected to the DC input of the DCDC converter.

A large snubber may not be required on the primary and in fact C17 acts as a snubber on the MOSFET.

Regards

John

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