TPS7A7100: Reverse Current Protection

Ryu Yamashita

Part Number: TPS7A7100

Hi team,

I have found that when the power supply stops, a reverse current flows and the device stops working.
As a stopgap measure, I added a Schottky barrier diode between output and GND.
Should I install one between output and input?

Sincerely,
Ryu

over 2 years ago

+1 Eunize Tobias over 2 years ago

TI__Expert 5500 points

Hello Ryu,

Yes, adding a Schottky diode between input and output protects the device from reverse current.

Best,

Eunize Tobias

0 Ryu Yamashita over 2 years ago in reply to Eunize Tobias

Genius 3785 points

Hello Eunize,

Thanks for the reply.
I understand now.

By the way, is there any reason why the connection between output and GND should not work?

Sincerely,
Ryu

0 Eunize Tobias over 2 years ago in reply to Ryu Yamashita

TI__Expert 5500 points

Hello Ryu,

Yes, if schottky diode connected between out and GND it wouldn't really protect the LDO from reverse current. When power supply stops there will still be some current flowing back to the device because Cout needs to be discharged and current will take the least impedance path. Also, when in normal operation the diode will be a clamping diode which limits the output voltage lower than nominal value.

Best,

Eunize Tobias

Power management

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TPS7A7100: Reverse Current Protection