BQ24650 MPPT stability question

BQ24650 achieves MPPT function through a close-coop control by detecting the MPPSET voltage.

First I would like to see the schematic for detail information to have better technical support.

If it's not suitable to post in forum, send it to our APPS/FAE via email.

I modified the bq24650EVM to set 260mA charge current and have 9.5V as VMPP to charge 2-cell battery. I set the input power supply to be 11V with 0.4A current limit to simulate the solar-panel. Using another resistor load connect at VSYS-GND to overload the input power, I can see the charge current decreases steadily from 260mA to 0 (disable termination) while input voltage is constant at 9.5V.

I can not duplicate the customer issue on EVM.

Suggestion:

1, verify the test on EVM without the temperature compensation. (Test 2 in above email must be wrong, 50mOhm gives 800mA Ichg instead of 80mA)

2, observe the Vin while we see charge current drops to 0 directly, make sure no other reason collapse the charger input.

3, when using a real solar panel, reduce the light brightness slowly to avoid solar panel output collapse due to weak light.

By changing the angle between the light and panel and/or inserting a paper (with hole) to partially block the light, we can simulate the cloudy/sunny condition.

Following are some test waveforms with real solar-panel as customer required. We can see the MPPT works stable.

Please double check the work condition and provide schematic/waveforms.

1) with and without solar panel temperature compensation to verify if it's a temperature compensation issue.

2) check waveforms to see if it's not a suitable MPP point setting. The solar panel might run out of the kneel-point and collapse.

It turned out customer’s solar module has a problem making the charging current up and down abruptly during the operation.

The customer has agreed that this is not our device issue.