Other Parts Discussed in Thread: BQ25896
Hi,
We have two battery-powered products with BQ25890 and we've got a few returns due to "dead" devices.
We suspect it happens when shipping mode is enabled, but we're unable to reproduce the problem in our lab.
When the product was returned we did some measurements around the BQ:
- VBAT: 3.45V
- VBUS: 0V
- VSYS: 0V
Since the devices can be externally powered/charged with a USB cable, we inserted a cable with power and did some new measurements:
- VBAT 3.45V
- VBUS: 5V
- VSYS: 0V
Tried toggling VBUS a few times, but the BQ would never power up the VSYS. The expected result is that it would exit shipping mode and power up the system.
A logic low on QON for around 1 second powers the system as expected.
Since our host is powered by VSYS we were unable to read the registers.
Are there any situations where toggling VBUS won't power up VSYS again?
I saw a post regarding BQ25896 where there was a known issue regarding I2C comm while entering ship-mode. Does this issue also apply to BQ25890?