PMP21160: Output Voltage

Adolfo Russo

Prodigy 140 points

Part Number: PMP21160

Hi,

The report assumes an output voltage of 24V +/- 5%.

Is there any easy way to modify the design to adjust voltage up to 28V even with lower performance?

thanks

over 3 years ago

0 Sheng-yang Yu1 over 3 years ago

TI__Expert 3650 points

Hi Adolfo,

The power stage design of PMP21160 will allow you to operate at 28V output. You will need to change feedback resistor divider and perhaps compensation values.

Regards,

Sheng-Yang Yu

0 Adolfo Russo over 3 years ago in reply to Sheng-yang Yu1

Prodigy 140 points

Hi Yu,

thank you very much for your feedback. I've prototyped the AC-DC using design files, I was able to go up to 27V decreasing the value of R232, then it stopped working. I will check again paying attention at compensation network,

thanks,

Adolfo

0 Sheng-yang Yu1 over 3 years ago in reply to Adolfo Russo

TI__Expert 3650 points

Adolfo,

You might also want to check why does the LLC stop working. Which protection was activated? ZCS avoidance? OCP? or other protection?

Regards,

Sheng-Yang Yu

0 Adolfo Russo over 3 years ago in reply to Sheng-yang Yu1

Prodigy 140 points

Hi mr Yu,

I guess it was OVP because I changed R205 to 60,4 kohm and I was able to raise voltage to 28V.

Can you advise for any limit to consider other than VCC when working with such high voltage?

thank you for your help,

Adolfo

0 Sheng-yang Yu1 over 3 years ago in reply to Adolfo Russo

TI__Expert 3650 points

Adolfo,

One limitation I could think of is the operation point is closer to the resonant tank gain peak. That means the operation range is narrower. I.e. can only cover narrower input voltage range.

Regards,

Sheng-Yang Yu

0 Adolfo Russo over 3 years ago in reply to Sheng-yang Yu1

Prodigy 140 points

Hi mr. Yu,

sorry to bother you, I have noticed that in the schematic C222 is placed on the collector side of Q204, while in the pcb layout it is placed on the emitter side.

Which solution is better?

thanks a lot for your help,

Adolfo

0 Sheng-yang Yu1 over 3 years ago in reply to Adolfo Russo

TI__Expert 3650 points

Hi Adolfo,

It is better to have a large capacitor at the input of the linear circuit to minimize the input voltage ripple to avoid it being switching on and off because of large input voltage ripple. That is why I place C222 to the collector side of Q204 eventually.

Regards,

Sheng-Yang Yu

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PMP21160: Output Voltage