Can I enable/disable an LDO (more specifically NCV8163AMX280TBG) by using the I2C SCL signal? This would allow me to turn ON the regulator once a master starts the I2C protocol and turn it off once the master stops communicating via I2C.
If possible, what extra components do I need (caps & diodes probably)?
Any help is appreciated.
PS: The I2C configuration is 1 master to N slaves.
PPS: the regulator turns on at 1.2V and the circuit will be powered from 3.3V
Details: This will be an array of small sensors and actuators built around STM8L001. There will be one STM8L001 for each sensor and actuator. There is a contraint on cost and the number of wires. Currently I have 2 wires for power + 2 wires for communication. When the master wakes up it needs a way to wake up the slaves as well.
I currently see the below options to enable this behaviour:
- 1 extra wire to drive the ENABLE pin on the LDO from the master (master wakes up, starts i2c, enables the GPIO that starts all the LDOs on the slaves)
- using MOSFETs to power up/down the entire power rail
- using the SCL signal to signal the ENABLE pin on the LDO
The sexiest option is the last one as it is the cheapest.
The below schematic is for the slave. As you can see it is a minimal design using STM8L001 with the ENABLE pin directly on the power rail.