I have a device that is powered off of a large battery. This device has peripherial ICs on it that consume power. Right now I have the input voltage through a switching regulator to 5 volts and then to a 3.3 volt linear regulator. This 3.3 volts goes to the entire board.

I also have a 3.3 volt regulator that is supplementary. This regulator is desired to power the MCU while being able to shut off the switching regulator to conserve power by only powering the MCU alone.

The schematic below shows what I am trying to describe. So 3.3_PERIPH_SHUTOFF is able to cut off the 3.3 rail from the rest of the board and turn on the supplementary regulator to power the MCU.

Then uC_PWR_CTRL is able to shut off the main power in.

D801 has been changed to a low ohm resistor.

Ignore the VUSB circuit.

But is this a good solution for a design that is able to sleep when desired, or is there a better way to do low power supply design?

Thank you

  • \$\begingroup\$ Hi, Did you really mean to delete the original schematic diagrams, a few hours ago? Although we can look in the "edit history" to see them, it seems strange to have a question which refers to diagrams which are not shown! \$\endgroup\$ – SamGibson Jun 14 at 17:36

There may be problems if you have unpowered peripheral devices connected to a powered microcontroller. You need to make sure that all microcontroller pins that are connected to these peripherals are set to a low voltage (logic 0) before removing power to the peripherals. Otherwise, significant current will flow through the input protection circuits of the peripherals.


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