Hello everyone,
I would like to know if there is any way to use a 3V Coin Cell battery backup for the NVCC_BBSM_1P8 power rail of the imx93 with the PCA9451A PMIC. As I must keep the RTC and Tampers working once the main supply has been shutted down, a Coin Cell backup is needed.
In the "4.1.3 Power architecture" section of the imx93 datasheet there is an image which shows the basic diagram for a backup battery.
I wonder if there is a way to connect the 3V CC to the PMIC. In order to achive an uninterrumpted NVCC_BBSM_1P8 (provided by LDO1), I must keep INL1 and VSYS above 2.7V due to the UVLO feature of the PMIC (which is impossible with a 3V CC). Anyway, a LDO with a CC would be pretty bad in terms of efficiency.
Is there any way to use a 3V CC backup alongside the PCA9451A to keep NVCC_BBSM_1P8 power rail on?
If no, is a power mux with ideal diodes needed to do a custom switchover between the PMIC's LDO output and a regulated (with a buck converter) 3V coin cell to manage this issue?
Best regards,
Gorka.
