I am currently devising ways to shut off different circuit sections in an embedded circuit. Here is a breakdown of what I am doing and my initial idea. Currently I have a micro controller which is sampling multiple analog sensors and in between sampling it goes on to sleep mode, but know due to the low power constraints in the specs, I would like to shut off some of the individual analog circuit sections (equivalent to each sensor circuit), my current Idea is through the use of Op Amps and ICs with shutdown support, however I am also wondering whether I can actually use an "IC" to cutoff the power to a circuit section based on a digital output or via a digital interface (I2C, SPI... ETC) which will allow me to completely isolate that section from the circuit, but is this possible?

Any Feedback or if you can point me to application notes, design notes, research papers, links... I would greatly appreciate it.

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    \$\begingroup\$ Off the top of my head, I would suggest logic control switch ICs - a MCU signal could be used to connect or disconnect power to whatever you want through the switches, as long as you consider the maximum current. Another option is to switch the power/ground from various components using transistors such as MOSFETs. \$\endgroup\$ Aug 29 '13 at 6:31
  • \$\begingroup\$ Apart from using components with a "shutdown" or similar capability, I've also used P-ch MOSFET's to switch power to subsystems on and off in the past. Which option you choose probably depends on what you're controlling. \$\endgroup\$
    – markt
    Aug 29 '13 at 8:19

For this case you can use the next one: (+1.8V is VCC in your case)

enter image description here

  • \$\begingroup\$ With a P-Channel MOSFET, assuming that you meet your Vgs(th) requirements, you don't need IC508 since it just complicates the circuit and doesn't really add much if anything. In that case, the resistor on the gate should be a pullup and not a pulldown. That way, when then uC is in reset or not fully booted, and the uC pin is tri-stated, the analog circuit defaults to being turned off. \$\endgroup\$
    – user3624
    Sep 3 '13 at 20:51
  • \$\begingroup\$ It really isn't clear how this relates in any way to the original question. \$\endgroup\$
    – Dave Tweed
    Sep 3 '13 at 22:15
  • \$\begingroup\$ He asked about how to shut off different circuit sections. I sent that image showing how to do it using a P Mosfet. \$\endgroup\$
    – Dante
    Sep 4 '13 at 20:39

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