Part Number:bq76930
Hi,
In a scenario where the bq76930 is configured with 6 cells, with all other settings being OK, data flash protection and PF settings all cleared to ease testing, we only had difficulty with CHG pin.
When 0x001F is written to 0x0 to set the pin high, the pin would go high for several hundred milliseconds, then low for over 10 seconds, then high, and continues this periodically.
To isolate the pin behavior, we removed Q5 in the PWR524A EVM which is connected to the CHG pin. We temporarily had some difficulty in resoldering it back, so what was described was only and exactly the behavior of CHG pin alone.
As Q5 is removed, the CHG is not applied to NFET Q4, so there is no actual charging current. We suspect the periodical behavior (the CHG is not always high) is due to some undocumented design: the DAC checks the current sensor, and drives CHG pin low and waits for several seconds for another test. We could not find any pertinent description in the documents.
This is urgent. Please kindly give us detail accounts of the CHG FET driver’s behavior.
Don