Distributed coulomb counter

A method of operating a battery management system, the method comprising:

• receiving, at an amplifier, having a gain setting, included in an analog front end (AFE) circuit, an analog signal representation of a battery current of a battery;
• converting, using an analog-to-digital converter (ADC) included in the AFE circuit, the analog signal representation of the battery current to a digital signal representation of the battery current;
• accumulating, at the AFE circuit, (1) a first value corresponding to a number of ADC sample cycles, and (2) a second value corresponding to an accumulation of the digital signal representation of the battery current for the ADC sample cycles accumulated in the first value;
• transferring, from the AFE circuit to a host microcontroller, the first value and the second value;
• and
• calculating, at the host microcontroller, a value representative of an accumulated charge transfer from the battery based upon the first value and the second value.

An analog front end (AFE) circuit for use in a charge transfer measurement system, the AFE circuit comprising:

• a gain amplifier, including gain amplifier inputs configured to receive a current of interest, and gain amplifier outputs to provide a signal representative of the current of interest and a gain setting of the gain amplifier;
• an analog-to-digital converter (ADC), including ADC inputs respectively coupled to the gain amplifier outputs, and providing a digital output representative of the current of interest;
• digital circuitry to (1) accumulate a first value corresponding to a number of ADC sample cycles of the ADC, and to (2) accumulate a second value corresponding to the digital output representative of the current of interest for the ADC sample cycles accumulated in the first value;
• and
• wherein the AFE circuit transfers a representation of the first value and a representation of the second value to a microcontroller, wherein the transfer occurs over a DC-isolated bus.