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+12V source switching (lowest part count, lowest cost)

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Jester

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I have done this a few times and the end solution never looks elegant.

I need to switch (control) a 500ma, +12V source ( with 5V logic). The switch must Source not sink.

Please show me your elegant solutions.

Here is a 4 component $0.40 solution

cheap.png
 

Rajnaveen

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Well you are using P channel Mosfet that will not work as I can see. Use NPN BD 139 Transister.
 

yassin.kraouch

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I have done this a few times and the end solution never looks elegant.

I need to switch (control) a 500ma, +12V source ( with 5V logic). The switch must Source not sink.

Please show me your elegant solutions.

Here is a 4 component $0.40 solution

View attachment 108620
what is the issue than ? yo uonly need to choose the right component rating, your circuit work perfectly
 

BradtheRad

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Last edited:

Jester

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what is the issue than ? yo uonly need to choose the right component rating, your circuit work perfectly

Yes it works, but can it be done with less than 4 components?
or
with less expensive components
or
both

- - - Updated - - -

Here is a 1 part SOT-363 165 mOhm $0.09 High Side 1A switch with extra parts for slew rate control. +/- 1.1A

View attachment 108625


Ding Ding Ding Ding Ding Ding ...... we have a winner

1/2 the parts in a small package for cheap:)

The +12V output will be connected to the load by the end user (ESD what's ESD?). Any suggestions for protection?

Thank you SunnySkyguy :)
 

dick_freebird

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Depending on some secondary values / concerns, a 5V
reed relay can be a nice simple and fairly reliable option.
Not as high a cycle reliability, but more resilient to some
overstress conditions (and providing isolation between
control and load, if that kind of thing matters).
 

D.A.(Tony)Stewart

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Electro-Static-Discharge = ESD . This part has protection with intrinsic diodes.

- - - Updated - - -

This is a half bridge (complementary) emitter follower. THis is equivalent to SPDT between V+ and gnd but with Vce-saturation voltage drops and use where low impedance is but voltage drop is not as important.
 

Jester

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Electro-Static-Discharge = ESD . This part has protection with intrinsic diodes.

- - - Updated - - -

This is a half bridge (complementary) emitter follower. THis is equivalent to SPDT between V+ and gnd but with Vce-saturation voltage drops and use where low impedance is but voltage drop is not as important.

I guess you did not catch my dry humor about ESD, I have had very limited success persuading most end users to take any ESD precautions with electronic equipment.
 

KlausST

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Hi,

If low side switching is possible, then a single n ch mosfet with low vgth will do.

Klaus
 

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