Tool/software:
Hello,
We are designing a space constrained device that uses a BLE MCU and an AFE for taking measurements. The BLE MCU can operate from 1.7 - 3.6 V, while the AFE requires 3.3 V.
We want to use the integrated LDO in order to avoid needing a separate BMS and LDO. Can the system be designed as follows?:
In the above design, we want to use BLE MCU as host to the BQ25155. During power up, the BQ5155 LDO would output 1.8V by default. Then the BLE MCU would change LDO output to 3.3V using I2C. After the LDO output becomes 3.3V, the AFE and BLE MCU are ready to communicate with each other. In this design the VDD and PMID outputs are not used.
We understand that 1.8V VDD of BQ25155 can also be used to power the host. However, we would prefer to keep the BLE MCU and AFE on the same voltage rail (avoids needing level shifter for SPI) and VDD has a limit of 10 mA.
We want to know if this design would be feasible given that the voltage level for I2C communication between the BLE MCU and BQ25155 is dynamic?
Thank you!
Crisvin K.
