BQ25601: input current detection

Peter Xu

Part Number: BQ25601

Hi team,

When I test on BQ25601, I can see REG07 BIT[7] is set to 1 and the input current limit is set to 2.4A at start-up period. But when I set the current limit to another value, then lower the input voltage to 4V and increase it back to 4.5V, the input limit is set to 2.4A again. This is weird because the input current limit detection is only applied in start-up period. I can see the charger is in VINDPM status but the chip did not shut down so the detection should not be applied when the input voltage rise from 4 to 4.5. But when I set the VINDPM to other value(default 4.5V), for example, 4.2V or 5V, the input current limit would not be reset. Can you help to check on this?

Test condition:

input voltage: 4.5V - 4V - 4.5V

battery voltage:3.8V

turn off watchdog timer

Others are default value.

Best Regards,

Peter

over 2 years ago

0 Ning T over 2 years ago

TI__Guru 58501 points

Peter,

For the input voltage, did you measure at the VBUS pin?

Thanks,

Ning.

0 Peter Xu over 2 years ago in reply to Ning T

TI__Expert 6205 points

Hi Ning,

I test the voltage on board(C1 PIN/TP3 and PGND), the voltage is accurate.

Forgot to mention that this only happens when SYS and BAT connect nothing. If a battery is connected(I use a power source here), Ilim will not be reset.

Regards,

Peter

0 Ning T over 2 years ago in reply to Peter Xu

TI__Guru 58501 points

Peter,

1. Did you test on the EVM?

2. Do you mean that when SYS and BAT are floating (i.e. only VBUS presents), the input current limit register (REG00[4:0]) may reset to default during your test?

3. Do you mean that when both VBUS and VBAT are present, the input current limit register (REG00[4:0]) will not reset to default during your test?

Thanks,

Ning.

0 Peter Xu over 2 years ago in reply to Ning T

TI__Expert 6205 points

Ning,

1. Yes.

2. Yes.

3. Yes.

Regards,

Peter

0 Ning T over 2 years ago in reply to Peter Xu

TI__Guru 58501 points

Peter,

It looks normal for VBUS = 4V - 4.5V.

Thanks,

Ning.

0 Peter Xu over 2 years ago in reply to Ning T

TI__Expert 6205 points

Hi Ning,

Could you please tell me the principle for this phenomenon? Thanks.

Regards,

Peter

+1 Garrett Kreger over 2 years ago in reply to Peter Xu

TI__Mastermind 32110 points

Hi Peter,

When you toggle the input supply below the VINDPM threshold then back above it the device sees this as a new input being plugged in and it resets the input current limit back to the original detected value of 2.4A.

Best Regards,

Garrett

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BQ25601: input current detection