BQ76952: BQ7695202

Hi Rahul,

1. What is the minimum & maximum value of equivalent Rsense Resistor in BQ7695202 IC? (This is required measured continuous current 500A.)

See below taken from the TRM. The maximum recommended Rsense value is 1mOhm. There is no theoretical limit on how small of a value you can use, however the voltage across the resistor due to the maximum current (including transients) should remain within the +/-200mV range of the ADC. It is also worth noting that as the resistor gets smaller, the maximum error of the current reading increases and the measurement resolution decreases.

For a maximum current of 500A, I would recommend Rsense = 0.2mOhm. This would mean that 500A * 0.0002 Ohm = 100mV across the sense resistor, leaving plenty of room for any transients to be properly measured by the ADC.

To calibrate the BQ76952 for this value, you just need to follow the steps in Section 2.6: Current Calibration of the BQ769x2 Calibration and OTP Programming Guide.

2. Condition Open Wire: DSG MOSFET OFF & CHG MOSFET ON, we need to configure both mosfet off in open wire condition.

See below, taken from the TRM, which describes how the Open Wire detection works on the BQ76952. An open wire results in a simultaneous Overvoltage (COV) and Undervoltage (CUV) condition. COV would turn off the CHG FET and CUV would turn off the DSG FET, so both FETs will turn off in an Open Wire condition.

Regards,

Max Verboncoeur