BQ24171: The condition of VREF disable

Shinichi Inoue

Guru 21721 points

Part Number: BQ24171

Dear Specialists,

My customer is considering BQ24171 and has a question.

I would be grateful if you could advise.

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According to the datasheet P.15 9.2 Functional Diagram and P.18 9.3.6 Power Up, when the AVCC>3.6V and AVCC > VSRN+90mV, the device exits sleep mode and VREF is enabled.

Are there any conditions for disabling VREF.

Although I supply 12V to AVCC, VREF is still disabled.

I think other condition of disabling VREF.

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I appreciate your great help in advance.

Best regards,

Shinichi

over 6 years ago

0 Jeff F over 6 years ago

TI__Guru**** 167196 points

Hi Shinichi,

I am not aware of another condition that disables VREF. At what voltage was SRN (i.e. the battery voltage) when you applied 12V to AVCC?

Regards,

Jeff

0 Shinichi Inoue over 6 years ago in reply to Jeff F

Guru 21721 points

Hi Jeff,

Thank you for your reply.

I'll share your information with the customer.

Also I confirm the voltage when AVCC(12V) applied and feedback.

I appreciate your great help.

Best regards,

Shinichi

0 Jeff F over 6 years ago in reply to Shinichi Inoue

TI__Guru**** 167196 points

Shinichi,

I haven't heard back from you so I will close this thread for now.

Regards,

Jeff

0 Shinichi Inoue over 6 years ago in reply to Jeff F

Guru 21721 points

Hi Jeff,

Thank you for your reply.

I couldn't receive any feedback from the customer.

So I confirm the customer again.

I will get back to you once I get any updates.

I appreciate your great help and patience.

Best regards,

Shinichi

0 Shinichi Inoue over 6 years ago in reply to Shinichi Inoue

Guru 21721 points

Hi Jeff,

I could get the response.

The customer could fix the problem.

As you mentioned, SRN is higher than AVCC, VREF wasn't output.

Could you please see below.

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I checked the voltage and understood the situation.

When DC = 12 V input

The AVCC voltage was dropped to 11.86 V by the resistors R1 and D1.

Since the SRN terminal is 12 V (shorting PVCC and SW),

Because the voltage is higher than AVCC, VREF was not output.

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I appreciate your great help.

Best regards,

Shinichi

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BQ24171: The condition of VREF disable