TPS51200: Vout still has 40mV after OCP and SCP

Stan Wu

Part Number: TPS51200

Hi TI,

We found there is a 40mV at TPS51200 Vout after OCP and SCP test. I didn't find any test waveform in datasheet or EVM document.

Looks like the controller still working and limits Iout at 50% current limit level then the power dissipation would be (1.2V-0.04V)*2A=2.32W?

Is it acceptable or just my misunderstanding? If it's acceptable, what's the theory? And how could we make sure the controller is without power / thermal risk at such condition?

Stan.

over 7 years ago

0 Qian Chen over 7 years ago

TI__Mastermind 24075 points

Hi Stan,

If the OC condition persists, TPS51200 will be heated up and will shut down when the jucntion temperature reaches 150c.

So there is no concern on thermal damage.

Thanks

Qian

0 Stan Wu over 7 years ago in reply to Qian Chen

Intellectual 580 points

Hi Qian,

So may I know why there is still a low Vout voltage at OCL condition? Does that mean the High side MOSFET still works in linear mode, correct?

Stan.

0 Qian Chen over 7 years ago in reply to Stan Wu

TI__Mastermind 24075 points

Hi Stan,

At OC condition, TPS51200 only limit current, it does not shut down.
If there is certain impedance between output and ground, with limited current, there is a low voltage on output.

Yes, the high side FET works in linear mode at OC condition.

Thanks
Qian

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TPS51200: Vout still has 40mV after OCP and SCP