Hello
Need some advise.
I am designing a simple power supply enable circuit. Please see attached schematic.
The On OFF switch would be logically "OR"ed together with a MCU GPIO.
The initial state of the POWER_HOLD_GPO would be LOW.
Once the ON switch is pushed, it will ENABLE the power regulator and also the MCU.
From then, the POWER_HOLD_GPO would be configured as output HIGH.
To turn off, when the switch is opened, it will drive the line LOW and the ON_OFF_SENSE GPIO (input) to the MCU will sense it and start the power down sequence and save criticial info. Once its done it will set POWER_HOLD_GPO low and it should shut off the power regulator.
My problem is, if during the power off sequence (ON_OFF_SWITCH =L & POWER_HOLD_GPO =H) and the MCU is within the power down sequence, and the ON/OFF switch is suddenly closed quickly enough prior the POWER_HOLD_GPO going LOW, the POWER_REGULATOR would be remain enabled, however the MCU has thought it would been powered down.
How do I avoid this state?
Any thoughts
Need some advise.
I am designing a simple power supply enable circuit. Please see attached schematic.
The On OFF switch would be logically "OR"ed together with a MCU GPIO.
The initial state of the POWER_HOLD_GPO would be LOW.
Once the ON switch is pushed, it will ENABLE the power regulator and also the MCU.
From then, the POWER_HOLD_GPO would be configured as output HIGH.
To turn off, when the switch is opened, it will drive the line LOW and the ON_OFF_SENSE GPIO (input) to the MCU will sense it and start the power down sequence and save criticial info. Once its done it will set POWER_HOLD_GPO low and it should shut off the power regulator.
My problem is, if during the power off sequence (ON_OFF_SWITCH =L & POWER_HOLD_GPO =H) and the MCU is within the power down sequence, and the ON/OFF switch is suddenly closed quickly enough prior the POWER_HOLD_GPO going LOW, the POWER_REGULATOR would be remain enabled, however the MCU has thought it would been powered down.
How do I avoid this state?
Any thoughts
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