The REG1 and REG2 LDOs in the BQ76942 device are for customer use, and their output voltages can be programmed independently to 1.8 V, 2.5 V, 3.0 V, 3.3 V, or 5.0 V. The voltage levels are selected using the Settings:Configuration:REG12 Config[REG1V_2:REG1V_0] and Settings:Configuration:REG12 Config[REG2V_2:REG2V_0] configuration bits as shown below. The LDOs are enabled using the Settings:Configuration:REG12 Config[REG1_EN] and Settings:Configuration:REG12 Config[REG2_EN] configuration bits, and their settings can be modified during operation using the 0x0098 REG12_CONTROL() subcommand. This subcommand takes an 8-bit value that matches the bits in the Settings:Configuration:REG12 Config configuration register. It is important that the voltage selection not be changed in CONFIG_UPDATE mode while the LDO is enabled.

The REG1 and REG2 LDOs and the REG0 preregulator are disabled by default in the BQ76942 device, with the REG1 and REG2 pulled to VSS with an internal resistance of ˜2.5-kΩ. If the pullup resistors for the serial communications are connected to the REG1 voltage output, the REG1 voltage can be overdriven from an external voltage supply on the manufacturing line, to allow communications with the device. The BQ76942 device can then be programmed to enable REG0 and REG1 with the desired configuration, and this setting can be programmed into OTP memory. Thus, at each later power-up, the device will autonomously load the OTP settings and enable the LDO as configured, without requiring communications first.