Hello everyone,
I am having a problem using the MP2720A charge controller. We are currently developing a control unit for a wearable device that is powered by a LiPo battery (Varta 1/LPP 443441 S PCM W). We are currently using the MP2720A charge controller for this battery. Unfortunately, we are receiving incorrect error messages from this controller. At the end of a charging cycle, we sporadically receive an error indicating that there is battery overvoltage. We checked this with an oscilloscope and could not detect any overvoltage. With another circuit board, we sporadically received an error during battery operation indicating that the battery and NTC were missing.
Attached are screenshots of the layout(Top & Bottom-Layer) and the Schematic. The jumpers JP6 and JP14 are bridged. The jumper JP11 is left open.
In the last 3 weeks I have already tried twice to get help via the contact form, but unfortunately I have not received a response.
Hi @janek.roessing,
Can you please provide screenshots from the oscilloscope at the time of the battery overvoltage event and NTC fault event? Also, how is the battery attached to the PCB?
Thank you, Will
Hi Will,
Unfortunately, I did not save the oscillograms and am unable to record them again at this time. However, I was unable to measure any overvoltage while the error occurred. Sporadically, there was a little noise, which caused voltages above 4.2V. The noise never occurred together with the reported overvoltage. A little noise should also be okay.
The battery wires are soldered directly to the pads shown in the screenshot. The cable length is approximately 30 mm.
Regarding the NTC/battery missing error: As described above, the error only occurs in battery mode, where no battery can be missing. If I have understood the data sheet correctly, the NTC is also evaluated primarily when charging the battery.