BQ79616-Q1: OV_THRESH hysteresis

Hi Alessandro,

Are you clearing the fault once the voltage is under 4.2V? The fault registers are constantly checking for an error. If you reset the register, and the OV fault is still there, the register will set itself to 1 again as the fault is still present. 

Regards,

David

I'm continuously (every 1s) checking and clearing the fault using the RST_OV bit in the FAULT_RST1 register. I see that the fault is cleared only if the voltage is under 4.150.

Hi Alessandro,

Can you tell me what the OVDAC value is after you see this behavior? The AUX ADC should be running in continuous mode and OVUV should be running for the OVDAC registers to be populated. The OVDAC HI/LO byte registers to read are 0x5D0 and 0x5D1 respectively.

The OVUV protectors compare the cell voltage with the OVDAC voltage reference to determine if the cell is over voltage or not over voltage.

Regards,

David

Hi David, the registers you mentioned have those values:

• REFOVDAC_HI - 0x5d0 = 0x5b
• REFOVDAC_LO - 0x5d1 = 0x97

Those values remain constant.

Again, the OV fault is triggered at the correct threshold (I set OV_THRESH = 0x23 = 4.200V) but the error can be resetted only if the cell goes under 4.150V