BQ25703A: Unexpected Register Change

Hideki Hayashi1

Part Number: BQ25703A

Hello team,

There are an unexpected behavior at the BQ25703A, and three questions.

・Behavior

When writing 0 from 1 at ChargeOption3 Register (I2C address = 35h) bit7: EN_HIZ, InputVoltage Register (I2C address = 0B/0Ah will be changed from set value.

This is checked by both reading resister and actual.

・Questions

1, Is this behavior expected?

2, I recognized that InputVoltage register is written when CHRG_OK pin is changed to H from L, but in above situation CHRG_OK pin is still not changed. Do you know other trigger to pull it up?

3, Is there any way to prevent to change InputVoltage register?

Regards,

Hideki

over 4 years ago

0 Kedar Manishankar over 4 years ago

TI__Mastermind 24075 points

Hi Hideki,

Is the VINDPM register being auto set to VBUS at no load - 1.28V even when toggling the EN_HIz bit?

0 Hideki Hayashi1 over 4 years ago in reply to Kedar Manishankar

TI__Expert 8390 points

Hi Kedar,

Did you mentioned that ChargeOption3 Register (I2C address = 35/34h) bit5 should be checked when toggling the EN_HIZ bit?

In the bits description, "measure VINDPM threshold" is written, but I don't know where they are or are used.

Regards,

Hideki

0 Kedar Manishankar over 4 years ago in reply to Hideki Hayashi1

TI__Mastermind 24075 points

Hi Hideki,

Read the input voltage register (0x0A and 0x0B) when you enable the converter by disabling EN_HIz

0 Hideki Hayashi1 over 4 years ago in reply to Kedar Manishankar

TI__Expert 8390 points

Hi Kedar,

The input voltage register will be 'Input Voltage bit 7-0 =0x05 or 0x06', equals 3.52V or 4.16V.

Note that the most customer's concern is that they don't want to change the register value.

Regards,

Hideki

0 Kedar Manishankar over 4 years ago in reply to Hideki Hayashi1

TI__Mastermind 24075 points

Hi Hideki,

What is the customer's input voltage? Inputting 0x06 in REG0x0A gives me 3.2V setting for the input voltage register (VINDPM)

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BQ25703A: Unexpected Register Change