MP2632 Charge current not as expected

Battery Management
1

We are having some problems with the charge current limit for the MP2632. We have designed it for 2A charging current but we are only getting 900mA charging current as measured by the volt drop across the sense resistor of 10 mOhms. Riset is 75K and we have a 200 Ohm resistor between DM1 & DP1 so believe the charger is using the charge current limit as set by Riset. Iilim resistor is 14.7K so should be set to 2.7A input limit.
We have tested the battery pack on a PSU and it wants to take 2A in constant current mode. We have looked at the voltage sensing lines from Rsense and do not see any appreciable noise on this signal.

The layout is not identical to the eval board but is close, could a lay out issue case this problem. Any guidance would be appreciated.

Kind regards

Ian

2

Hi Ian,

It’s a bit difficult to diagnose and troubleshoot your issue like this, please send the issue over to mpsnow@monolithicpower.com along with your schematic and layout so I can review everything for you. Anything you can tell me about your test set up will be beneficial as well.

Thanks,
Brendan Schoemehl
Field Applications Engineer
Monolithic Power Systems | MPS Now

3

Hello!

I have the same problem. Instead of the 3A i need, the best I cant get is 1.2A while charging.

What could be the problem?

Thanks,
Ginjo

4

Hi Ginjo,

Thank you for contacting the MPS forum. Can you tell me what your testing set up is? Are you using our evaluation board or your own custom PCB?

Thanks,
Brendan