All the data collected was using the BQ40Z80 device, which follows the SBS guidelines, BQ25750 device with the I²C protocol, and MSPM0L1306 in between to translate.

The MCU polling the gauge is shown below.

The SMBus structure observed follows the structure in Section 3.4. Also note that the data received is little endian. Charging Voltage: 0x6018 = 24600mV and Charging Current: 0x0866 = 2150mA. Note: This is before the gauge settings were changed to what is shown in Figure 3-2.

The MCU sending ChargingVoltage() and ChargingCurrent() to the charger is shown below.

The I²C structure observed follows the structure in Section 3.4. Also note that the data transmitted is little endian. 24600mV ChargingVoltage() is scaled to 31 = 0x001F for the charger FB regulation target (following the logic in MCU Code Example) and charging current: 2150mA is scaled to 172 = 0x00AC. The address registers for the voltage and current are 0x00 and 0x02, respectively.

The complete charging profile can be seen below.

Figure 3-12 illustrates the test result using test set up discussed in the previous section. The result follows the gauge setting detailed in Table 3-1 and charge profile in Figure 3-1. Charge current is first regulated to the charging current at low voltage setting. Once the battery voltage reaches the Medium Voltage Threshold setting, charge current is increased to charging current at medium voltage. Then, current drops to charging current at high voltage once the battery voltage is increased to High Voltage Threshold. Then, the charger enters constant voltage mode once the battery reaches the Max Charge Voltage. In constant voltage mode, the current tapers until the current reaches Termination current. The termination in this application is handled by the charger because, once the charger reaches termination current, the charger disables the charge. The termination can by handled by the gauge and MCU if needed, which can be done by disabling the enable termination bit in BQ25750.