JAJSSA8 November 2023 BQ76905
PRODUCTION DATA
The BQ76905 integrates a delta-sigma voltage ADC that is multiplexed between measurements of cell voltages, an internal temperature sensor, an external thermistor, as well as performs measurements of the voltage at the VC5 pin, the internal 1.8-V LDO voltage, and the VSS rail (the latter two are for diagnostic purposes). The BQ76905 device supports measurements of individual differential cell voltages in a series configuration, ranging from 2-series cells to 5-series cells. Each cell voltage measurement is a differential measurement of the voltage between two adjacent cell input pins, such as VC1–VC0, VC2–VC1, and so on. The cell voltage measurements are processed based on trim and calibration corrections and then reported in a 16-bit resolution using units of 1 mV.
The ADC takes its input from the ADC multiplexer and generates a high-speed digital data stream, which is digitally filtered to produce a 24-bit output. The ADC uses the 262.144-kHz LFO clock as its sampling clock. The digital filter includes programmable decimation rates, which result in data generated at different intervals and with differing resolutions. The effective resolution (defined as the resolution such that the data exhibits 1-sigma variation with ±1-LSB) of the ADC conversions changes as the decimation rate changes, with effective resolution increasing as the output rate is reduced.