BQ34Z100-G1: Reverse Polarity Protection for NiMH

Hi Jerry,

We do not have a chip that protects from reverse polarity. With reverse polarity, you will be violating the absolute maximum minimum voltage of the IC which is -0.3V. The device could get damaged.
thanks
Onyx

What about putting some series resistance on the VBAT pin?

i believe that will just limit the current

Onyx Ahiakwo said:

i believe that will just limit the current

That's correct Onyx,

Is there a reasonable resistor value where a battery reversal won't damage the IC (by current limiting) and will not cause a significant error when reading the battery voltage in normal operation?

Kevin,

The ADC input for voltage measurement is high impedance. On our other gauges, we tend to use resistor values between 10 and 100 ohms.

thanks

Onyx 

Those values seem rather low to protect against a battery reversal (input pin latch-up). If the A:D is truely high impedance, then probably a value >1K can be used.

...kevin

Some of our multi-cell gauges use 1k so you might be able to get away with that.
thanks
Onyx