TPS25942A: Current draw on secondary input when not in use - is it normal?

Hello,

I am new to the TPS25942A I/C and I am currently using the development board to test. On the original dev board, U2 is a TPS25942L but I replaced it with an 'A'. This said, I have also desoldered R7 so that both outputs are isolated.

On input 1 (to U1), I have a regular 12V power supply.

On input 2 (to U2), I have a 6V battery (two CR2 in series).

I changed a few of the resistors so that the inputs would match my requirements (input 1: 3.7V-18.5V, input 2: 3.7V to 8.3V).

The goal is to have both outputs tied together and use input 1 as the main input. If input 1 is disconnected, it will automatically switch to input 2.

So far, when input 1 drops and reaches a threshold, then input 2 is selected. I can confirm my ranges are working by monitoring the inputs and outputs of both circuits.

However, here's the problem: unless I'm missing / not understanding something, I was expecting input 2 to be totally isolated when input 1 is driving. I do spot checks at input 2 with a multimeter and it seems that my 6V battery is draining at a rate of around 1mV per minute therefore my battery will not last more than a day or two... which is totally the opposite of what I am trying to accomplish.

Am I doing anything wrong?

Thanks for any help.

Benoit