Tool/software:
Hi TI team,
I'd like to check if the BQ24780S' ACOVP threshold will be affected by rise time or battery?
These days we find about 4pcs NG boards(ACOK issue) on our production line.
Phenomenon:
Battery voltage:11.1V; ACDC output: 24.56V. VCC = 23.93V(The diode voltage drop is about 0.6V.)
- Battery connected: First time plug in ACDC adapter, ACOK is high, charging normally. Pull out the ACDC and plug in again, ACOK is low. Seems that an error is locked.
- Battery not connected: Every time plug in ACDC adapter, ACOK is high. The board works normally.
- Without battery, increasing ACDC output from 24V, when the ACDC output is 25.6V, the ACOK is low. Suppose the OVP threshold should be 25.6V.
- With battery, increasing ACDC output from 24V(the board is charging), when the ACDC output is 24.6V, the ACOK is low. Seems the threshold is changed.
CH2—BQ24780S_VCC pin
CH3---BQ24780S_ACOK pin
VCC normal voltage is 24V.
Condition: With battery. Twice plug in ACDC.
2nd time pull out the ACDC, when the VCC voltage goes down to 23.4V, the ACOK is pulled up shortly.
Every time plug in the ACDC, the VCC has a voltage spike, suppose it can be ignored by deglitch time.
This issue can be solved by increasing the VCC voltage rise time. The VCC pin voltage rise time is about 40us, we changed it to be 10ms, the issue can be solved.
I can't find the related information from the datasheet, can anyone help to explain it for me ?
Thanks.
Best regards.
Kylin
