TPS56628: BACKDRIVE ISSUE

jitheesh pathayapurakkal

Part Number: TPS56628

im using the TPS56628DDA regulator part in my board.for this regulator 12v is giving as Vin & EN and generating the output of 5v.

while im giving 5v to the power rail from usb type c and not giving power to the regulator input ,it becomes floating and backdrive happens getts 5.5v in the 12v power rail.

so how to avoid the backdrive of the regulator ?give me some solutions for that.

over 6 years ago

0 Jason Wang (BSR-MV) over 6 years ago

TI__Genius 9550 points

Hi,
I am looking into this request and will give you feedback on Monday. Also, please upload your schematic.

0 Neal Zhang over 6 years ago

TI__Expert 4720 points

Hi jitheesh,
the solution is you can add a diode between the regulator output and the usb type c.
Yes if you have output prebias, the HS MOS parasitic diode will make the input to 5.5V.

0 jitheesh pathayapurakkal over 6 years ago in reply to Neal Zhang

Prodigy 50 points

Anyone could please explain how the backdrive happens in the regulator ? what the reason for that ?

0 Neal Zhang over 6 years ago in reply to jitheesh pathayapurakkal

TI__Expert 4720 points

Hi jitheesh,

it's because of the HS MOS's parasitic diode. It will conduct when Vin<Vout.

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TPS56628: BACKDRIVE ISSUE