BQ25601D: Extremely low charging

Hi Carolina,

Can you please send me a snapshot of your registers?

Best regards,

Angelo

Hello, today I have been working in DCP mode which also allows 2.4A, but having the same result.

At the beggining, I just check that the USB adaptar is well recognized.  Then I set the pin to start the chaging process. If the charging current is low, then it works fine.

But as you can see, If I set the charge current at 960mA in REG02, then the input current is changed in the REG00 0x04.

Hi Carolina,

Thanks for sending your register settings.

My understanding of your issue is as follows (please correct me if any of this is wrong). Initially, the BQ25601D correctly detects a DCP and sets the input current limit to 2.4 A. However, after you increase the ICHG setting from 0.48 A to 0.96 A, the input current limit register is set to 0.5 A, so the actual charge current is lower than 0.96 A.

I tested this on an EVM and was unable to duplicate your issue. When I increased the ICHG setting from 0.48 A to 0.96 A, the input current limit stayed at 2.4 A, as expected.

As a quick sanity check, can you try manually setting the input current limit register to 2.4 A and see if the BQ25601D can provide a 0.96 A charge current in that case?

Finally, there are some discrepancies in the 3rd picture you sent. The REG07 and REG08 values in the top line do not match the REG07 and REG08 values below the top line. Which data is correct?

Best regards,

Angelo

The right values are the ones in the bot, it takes some time to update them on top line.

If I try to set the input current register manually, then the carge stops and it begins the circle again (Good detection os USB, start charging, modify input current). So it is reseting the charging all the time if I try to set the input current value to a higher one than 0x04.

Could it be a problem with the voltage needed on the battery to reach that current? or the IC should be able to increase the charge voltage until the charge current is achieved?

Another weird thing is that when I read the register 11, I cannot read the value of the chip BQ25601D : 0111(bit6:3). I read 0x11.

The name of the chip is clearly written on the top, so it is not posible to have an incorrect part number from the distributor. Could this be the origin of the problem? The fives prototypes I have assemble have the same error on the register.

Hi Carolina,

REG0B[6:3] should actually be '0010.' '0111' is a typo in the datasheet, so thanks for bringing this to our attention. Like you, I also read 0x11 from REG0B from an EVM, so this isn't an issue.

A few more questions:

1) Are you manually shorting D+/D- to simulate a DCP, or are you using an actual DCP adapter?

2) After the 2.4 A input current limit is set to 0.5 A, does forcing input detection using the IINDET_EN bit correctly set the input current limit back to 2.4 A?

3) Can you please capture a waveform that shows VBUS, IBUS, VBAT, and IBAT the moment when you increase ICHG from 0.48 A to 0.96 A, thus causing the input current limit setting to fall to 0.5 A?

Best regards,

Angelo

Hello Angelo,

Thank you for the support, but I have given up with this chip. I have changed it for the BQ24190, which is almost compatible, just a few changes and the circuit is already working propperly. 

Regards,