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UCC2805: PSU

Part Number: UCC2805
Other Parts Discussed in Thread: UCC2813-5


Good Day.

Customer would like to ask you a few questions that arise in the framework of a new design that currently is being developed.

The new PSU design is indented for automotive use and will be based on a flyback converter (or any other alternative cost effective solution) with multiple output windings in order to create the 5.6V (regulated) and 15V (isolation required) bus voltages. 

PSU design requirements:

Input Voltage: 8 to 26V    Input voltage should also pass the ISO16750-2 Level 2 (Voltage dip 4.5V for 15ms)   (features GND)

Vout 1: 5.6V (1A)     (features GND1)

Vout 2: 15V (2A)      (features GND2)

The IC that seems to fit in our design requirements is the UCC2805D due to the UVLO restrictions. The only drawback for us is the optocoupler that is used as a feedback for voltage regulation. 

Is it possible to use an auxiliary winding (or tie GND and GND1 and use a resistor voltage divider)for voltage sensing and feed it to the FB pin of the IC in order to eliminate the optocoupler?

Do you purpose any alternative IC for those design requirements?

Please advise. Thank you very much.

Best Regards,

Ray Vincent