BQ24171: IC permanently in error state.

Alexei Trushnikov

Part Number: BQ24171

Hello!

We need for technical support on BQ24171 device application. Our scheme is attached below; voltage levels are highlighted in red.

Scheme functioning doesn’t match the specifications, particularly paragraph 9.3.9 (Enable and Disable Charging). IC is in error state with 0.5 Hz output on STAT pin. As a result, IC doesn’t charge our cells. There is no any activity on SW pin.

We need to know:

- Are there any reasons for BQ24171 to be in error state except for the ones mentioned in 9.3.9?

- What can we do to find out why BQ24171 is in error state?

over 7 years ago

0 Steven Bangdiwala over 7 years ago

TI__Expert 8690 points

Hi Alexei,

A few things to try:
1. The TS pin voltage may be triggering charge suspend, it is almost hitting the cold threshold. Try to force a voltage of 2V on TS.
2. Pull TTC high to VREF, this should disable safety timer.
3. If that doesn't work, provide scope shot of V_PVCC, V_SRN, VREF and STAT

Regards,
Steven

0 Alexei Trushnikov over 7 years ago in reply to Steven Bangdiwala

Prodigy 30 points

Steven,

Thanks a lot for your attention.
1. We tried to put voltage in range of 1.5-3.5 V on TS pin, situation has not changed.
2. We tried to pull TTC pin on VREF - the same result.
3. Voltages on mentioned pins are seems like DCV without any disturbances.
May be have any ideas?

Best regards, Alexei

0 Steven Bangdiwala over 7 years ago in reply to Alexei Trushnikov

TI__Expert 8690 points

Alexei,

Can you provide a scope shot when you input the adapter? Show AVCC, PVCC, ACDRV and VSRN. I'm thinking there is too much delay between input adapter and ACFET turning on.

Regards,
Steven