How to turn off power supply with a switch

[ebuddy]

I have an IC on PCB board. I'll need to put a switch to turn off the +5V power to the IC from time to time. However, I only have "normally-off" switch in hand. Anyone knows how to do this? Thanks.

 

[rohitkhanna]

You'll need some additional circuitry. Something to "invert" your normally=off switch. So when your switch is OFF, the circuit (power to IC) is ON, and vice-versa. A simple BJT/ FET/ MOSFET/ Relay comes to mind. Take our pick & work it out.

cheers!

 

[goldsmith]

Dear ebuddy
Hi
It depends on how much is your required current through switch and how much should be the frequency of turning off and turning on .
Best Wishes
Goldsmith

 

[mister_rf]

To use a single switch he may use the bistable flip-flop which can be toggled between states with a single push button.

See some details here:
http://www.bowdenshobbycircuits.info/page9.htm
**broken link removed**


By the other hand we can change the relay by a P channel MOSFET. :grin:

 

[ebuddy]

Dear ebuddy
Hi
It depends on how much is your required current through switch and how much should be the frequency of turning off and turning on .
Best Wishes
Goldsmith

The current is several mA, and frequency of switch is very slow (manual switch). Thanks.

 

[rohitkhanna]

To use a single switch he may use the bistable flip-flop which can be toggled between states with a single push button.

See some details here:
http://www.bowdenshobbycircuits.info/page9.htm
**broken link removed**


By the other hand we can change the relay by a P channel MOSFET. :grin:

Nice overkill mister_rf ... LoL !!

Here's a simpler one. Just chose a relay which works with 5v or whatever your Vcc is.

 

[mister_rf]

You don’ t get it… I understand there's push-to-make switch available, that returns to its normally open (off) position when you release the button, so using that diagram you may keep a closed circuit after pressing the button and disconnect the load for a second push, and that's similar to a toggle switch. :roll:

 

[rohitkhanna]

I'm not quite sure the question asker wants a 'toggle' switch. Does he ? He just wants to disconnect an IC's power when he presses a switch.
The principle used here is know as the "KISS".

Maybe you've heard/ read of it ?

cheers!

 

[goldsmith]

The current is several mA, and frequency of switch is very slow (manual switch). Thanks.

Hi again
You can use a simple opto coupler for this aim . or a simple BJT . in series with ground path .
Best Wishes
Goldsmith

 

[papunblg]

I have an IC on PCB board. I'll need to put a switch to turn off the +5V power to the IC from time to time. However, I only have "normally-off" switch in hand. Anyone knows how to do this? Thanks.

Buy. Buy one switch as per your requirement.

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ebuddy,
Learn and get idea from all the posts. Also consider time and money required to make changes to your normally off switch.
Consider feasibility for your case.