I’m using the MP2672A in the host control mode with RISET at 6.04K. When charging, the charging current I’m seeing is about 30% below what I expect.
I’m measuring the current right at the battery. I used a few ICC settings. Here is what I’m getting:
| ICC |
Current (A) |
Expected (A) |
%Drop |
| 1111 |
1.35 |
2 |
32.5% |
| 0011 |
0.535 |
0.8 |
33.1% |
| 1100 |
1.2 |
1.7 |
29.4% |
| Here is what I’m reading at the I2C bus when ICC is 0011: |
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At other ICC values, the numbers are the same, except for REG[1], which reads the ICC.
I tried this on two different boards with exactly the same results. The battery voltage when this occurs is about 7.5V. This is the battery voltage, not the charging voltage.
My schematic is like this:
Any ideas why this is?
Hello @igal.brodetsky ,
Thank you for bringing this matter to our attention. To help us clarify your issue, are you seeing this drop off only when the battery reaches 7.5V? Does the charging current ever reach the expected Icc? Furthermore, does the battery voltage continue to increase to your desired Vbatt?
From your register settings in the example screenshot, register 1 show that the IC is reading an output current of 0.8A. These register readings can be found on page 29 of the datasheet for your reference.
Hi Ryan,
The current is 30% low during fast charging phase independent of the battery voltage. I discharged the battery down to about 6.7V and are still seeing the same lower charging current.
The battery voltage does increase and the battery charges just fine, just at the lower current than expected.
As far as the register settings. I set them to 0.8A through my firmware code, but the current I’m measuring in this particular case is only 0.535A.
Hello Igal,
Thank you for your response and your patience. Would you be able to probe the CV pin and let me know if it’s tied correctly to VCC? I notice that you have a 2k resistor there as a tie to the pin, but the datasheet states that it should be connected directly to VCC in host control mode. Are you also able to confirm that your inductor is not saturating during operation?
Furthermore, to make sure that we are on the same page, I want to confirm that your input voltage is 5V.
