MP2632 SYS On/Off Vin Detect

I am designing a circuit for a new product. It is a small handheld device about the size of large coffee mug. It will run on a wall adapter and internal batteries. There are no USB functions involved.

I have been using the EV2632 eval board for testing and as the basis for the product PCB. Charging current limits and output current limits are as designed and expected. No issues there.

Two questions though.

The first is around power on/off. The device must go into charge mode automatically when the wall adapter is plugged in. (Vin is present) It is preferred that Vsys not go on automatically. So I would think that the PB input needs to get a short pulse to do this. I am I correct that just a cap between PB and the ground connector on the incoming power jack would work?

The problem though is that Vsys would than also be present and turn the unit on which is not supposed to happen. To resolve that, I could have the main power switch be a DPST non-momentary switch. One side of the switch would have its cap that would also give the PB input its pulse that would put IC into boost mode. The other side of the switch would switch the now present Vsys to the rest of the product.

If all of that is correct, turning the power switch off would remove Vsys internally thus putting the IC into low load current mode. The IC would then shut down after the internal timer went off.

Am I correct in all of this? If not, some guidance would be appreciated.

The second queston is in regards to multi-cell unbalanced charging. Is this IC OK to used this IC to charge 4 18650 cells in an unbalanced configuration?

Thanks for your help.


Hello Bob,

I will take a look into your question and respond as soon as possible.

Thank you,
Vinh Tran