TPS1HA08-Q1: Automatically reverse protection issue

Jason Fan

Part Number: TPS1HA08-Q1

Hi Experts:

I'd like to know the condition which could trigger the auto - reverse protection in TPS1HA08-Q1, as the description in datasheet ,

"In the reverse battery condition, the switch will automatically be enabled (regardless of EN status) to prevent
power dissipation inside the MOSFET body diode. In many applications (for example, resistive load), the full load
current may be present during reverse battery."

Currently , customer do the test that reverse connecting the 12V on the device , and found the 0.4V voltage drop from Vout to Vbb, it seems the function is not triggered and the reverse current go through the internal body diode.

Please look at the below schematic , the SEL2 is connected to ground by resistor

over 5 years ago

0 Anthony P Pham over 5 years ago

TI__Mastermind 23410 points

Hi Jason,

We do recommend a few options in addition to the automatic switch feature to block reverse current in the system:

Blocking FET or diode in series with the battery supply
Blocking diode in series with the GND node of the high side switch

0 Jason Fan over 5 years ago in reply to Anthony P Pham

TI__Intellectual 1705 points

Hi Anthony:

Thanks for your reply.

My question is whether the automatic switch function take effect or not , the voltage drop between the Vout and VBB is too big if the internal FET turn on ,

And the reverse current we test is only 1A. it doesn't make sense.

0 Anthony P Pham over 5 years ago in reply to Jason Fan

TI__Mastermind 23410 points

Hi Jason,

Understood.

Is there are reason for C9 and C11 being from the VBB and VOUT?

Power management

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TPS1HA08-Q1: Automatically reverse protection issue