LM5022: LM5022 (PMP20497) OCP Adjust

Kami Huang60

Part Number: LM5022
Other Parts Discussed in Thread: PMP20497

Dear Sir/Ms.

My customers refer to the PMP20497 to design their products but now find the problems to trigger OCP.
www.ti.com/.../PMP20497
Customer specifications
Vin: 12V~56V
Vout: 55.5V/1A (system load 0A~0.6A)
The customer has sent us the PCB and circuit diagrams, and I can't touch the OCP with CT and R14. I see that the voltage of R12-R13 from the oscilloscope is 168mV.
Can you guide us how to adjust the parameters of OCP?
If you want customer's circuit diagram and other information, please email me. If you have a MathCAD (R14, R15) file, please email me.

Best Regards,

Kami Huang

over 5 years ago

0 Garrett Roecker over 5 years ago

TI__Mastermind 21720 points

Hi Kami,

Thanks for reaching out with your question

Can you please measure the voltage across C17? This will help us understand what the current sense pin is seeing. Please attached the waveform in you next post. R14 is used to reset the current sense trans former during the off time of the switch.

Also are you using the exact schematic from PMP20497? Are all the components the same?

Thanks,

Garrett

0 Kami Huang60 over 5 years ago in reply to Garrett Roecker

Genius 3830 points

Hello Garrett,
No! Customer Not design Same components Because not same output spec. If you want to know more detail, please give me your Email. I can email schematic and transformer spec. to you.
Best Regards,
Kami Huang

0 Garrett Roecker over 5 years ago in reply to Kami Huang60

TI__Mastermind 21720 points

Hi Kami,

I sent you a friendship request. Please accept and you can send me the schematic directly. Please also send the waveform of the voltage across C17.

Thanks,

Garrett

0 Ronald Lin over 5 years ago in reply to Garrett Roecker

Prodigy 50 points

Hi Garrett

Another question.
Can I remove flyback transformer auxiliary winding?
When I remove D2,the system seems work normally.

Thanks,

Ronald Lin

0 Garrett Roecker over 5 years ago in reply to Ronald Lin

TI__Mastermind 21720 points

Ronald,

If the auxiliary winding is not needed then it can be removed.

Thanks,

Garrett

0 Kami Huang60 over 5 years ago in reply to Garrett Roecker

Genius 3830 points

Hello Garrett,
Thanks for your help. Ronald is our customer RD.
BTW, I don't see friendship request.
Best Regards,
Kami Huang

0 Garrett Roecker over 5 years ago in reply to Kami Huang60

TI__Mastermind 21720 points

Hi Kami,

The friendship request should so up under your profile summary page. Accept it and you can directly message me.

-Garrett

0 Kami Huang60 over 5 years ago in reply to Garrett Roecker

Genius 3830 points

Hello Garrett,

I can not find. Sorry that I'm not at home int E2E user interface.

Best Regards,

Kami Huang

Power management

Power management forum

LM5022: LM5022 (PMP20497) OCP Adjust