BQ25798: Unable to set EN_HIZ and EN_MPPT

David P

Part Number: BQ25798

Tool/software:

Hello TI,

We have an issue where we are trying to write a values to EN_HIZ and EN_MPPT. After write these values do not stick. Watchdog is disabled. The write succeeds (i2c does not complain), but on the next read our values are not there.

What else do we need to do to be able to write those two bits?

Thank you,

David

over 1 year ago

0 David P over 1 year ago

Prodigy 20 points

Another interesting observation:

I2C at 400kHz wont write the EN_MPPT bit. At 100kHz that bit is written and the IC starts to charge.

Now once we switch the MPPT on some caps are whistling, and the ADC (VBAT, VSYS, ...) values go crazy. They don't reflect reality.

Any ideas?

0 David P over 1 year ago

Prodigy 20 points

Well even at 100kHz EN_MPPT does not stick reliably. There must be another condition which block EN_MPPT from being enabled, but I don't see it mentioned in the documentation.

0 Christian Moyer over 1 year ago in reply to David P

TI__Mastermind 31551 points

Hello David,

Can you provide your register values?

What is battery voltage?

What is REG0x1E[4]= ?

Best Regards,

Christian.

Power management

Power management forum

BQ25798: Unable to set EN_HIZ and EN_MPPT