BQ24171: How to detect the adapter is not presented

Leo Yang

Expert 3735 points

Part Number: BQ24171

Tool/software:

Hi team,

How could we know if the adapter is removed from the charger if the system CPU needs to know?

Can I use BATDRV pin to drive the MOSFET and give the high/low status to CPU at the same time?

Is BATDRV pin pulling high only when the adapter is removed (Battery discharge)?

Thanks,

Leo

7 months ago

0 Jeff F 7 months ago

TI__Guru**** 154406 points

Hi Leo,

Yes, you can use BATDRV going high to indicate when adapter is removed.

Regards,

Jeff

0 Leo Yang 7 months ago in reply to Jeff F

TI__Expert 3735 points

Hi Jeff,

Thanks for answering.

Can I use ACDRV? I read the datasheet and it seems that this pin goes down when the adapter removed immediately.

BATDRV goes down after SYS voltage is lower than VBAT.

Another question is if the Vbat is 10.89V, could the charger support that output when the Vin is 12V?

I am considering the duty radio.

Thanks,

Leo

0 Jeff F 7 months ago in reply to Leo Yang

TI__Guru**** 154406 points

HI Leo,

Yes, ACDRV can be used as well. .You might test REGN and VREF as well.

The max duty cycle = VREG/VIN is 97%.

Regards,

Jeff

0 Leo Yang 7 months ago in reply to Jeff F

TI__Expert 3735 points

Hi Jeff,

Should REGN be a 6V stable LDO voltage?

I don't get what you say for The max duty cycle = VREG/VIN is 97%. please let me know, thank you.

Leo

0 Jeff F 7 months ago in reply to Leo Yang

TI__Guru**** 154406 points

Hi Leo,

REGN is output of the LDO. The LDO is powered from the input to the charger. I can't recall if REGN is available from battery only power. You can test on an EVM if REGN is available when only battery is attached.

The max duty cycle for a buck converter is VOUT/VIN = VREG/VIN=97%. 10.98V/12V = 91.5%<97%.

Regards,

Jeff

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BQ24171: How to detect the adapter is not presented