Since the SBS specification defines the registers for charge current and charge voltage, there is no setup needed on the charger side. Voltage, current, and temperature are sensed by the gauge and the appropriate charge current and charge voltage is sent to the charger based on the Advanced Charge Algorithm settings.

The control loops in the charger will limit the current to the programmed ChargingCurrent()from the gauge during the Constant Current (CC) phase of charging, and then the charger will limit the charging voltage during the Constant Voltage (CV) phase based on the programmed ChargingVoltage() from the gauge.

Most TI chargers that use SMBus are SBS compliant and considered level 2 smart chargers. This requires them to accept ChargingCurrent() and ChargingVoltage() commands to the 0x14 and 0x15 addresses respectively.

The SBS Specification⁽¹⁾ states the ChargingVoltage() data range is from 0 to 65,534 mV with +1% to –9% accuracy in voltage regulation while there is a good power supply attached. The ChargingCurrent() has the data range from 0 to 65,534 mA with ±5% accuracy. This must be for both the gauge and charger. See the ChargingCurrent() (0x14) section and ChargingVoltage() (0x15) section of the SBS Specification for more information on exceptions.

For the I2C-based system using the BQ28Z610-R1, the charger also does not need to be configured for the application. The gauge will write directly to the charging voltage and charging current registers in the charger after they are set in the gauge.

The BQ25730 is an I2C-based charger that has 2-byte charge current and voltage registers, the BQ28Z610-R1 can be configured to work with the BQ25730 charger because of its 2-byte registers that do not have any other configuration information in the registers. Refer to Section A for more information on the charger setup.