TPS7A25: voltage over spec(5V+5%) when OCP and soft start

Ann_Lien

Part Number: TPS7A25

Hello expert,

My customer is using TPS7A2501 in their IPC application. Please see below waveform OCP and soft start period. It seems like voltage is over customer's spec during these two conditions. May I know if you can help to double check if we have any method to solve it? I can send you the schematic offline and please kindly help to check if we can add Cff or other external component to solve this overvoltage issue. Thanks a lot!

Best regards,

Ann Lien

over 2 years ago

0 Ann_Lien over 2 years ago

TI__Genius 10640 points

CH1=Iout, CH2=Vout, CH4=Vin

Soft-start - Vout waveform

0 Ann_Lien over 2 years ago in reply to Ann_Lien

TI__Genius 10640 points

Hello expert,

Customer found out it might be related to too fast turn on time. Do we have LDO could support 7V->5V/200mA application with adjustable SS time? Thanks a lot!

Best regards,

Ann Lien

0 Nick Butts over 2 years ago in reply to Ann_Lien

TI__Mastermind 37925 points

Hi Ann,

I am not sure I understand the 'scope trace. It looks like the LDO is operating in dropout during this OCP event. Why is VIN low (~5V) until the OCP event and then shoots up to ~7V? I have a feeling the overshoot is amplified because VIN is not held above the dropout region during the transient.

Could you please send me the schematic offline? I'll keep this thread open and continue support here besides the schematic.

Regards,

Nick

0 Ann_Lien over 2 years ago in reply to Nick Butts

TI__Genius 10640 points

Hello Nick,

Okay and I will send you schematic for your reference. Thanks a lot!

Best regards,

Ann Lien

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TPS7A25: voltage over spec(5V+5%) when OCP and soft start