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

[Jester]

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

 

[Rajnaveen]

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

 

[assu]

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

What you have to say about this?
https://www.falstad.com/circuit/#$+...+0+64+0+35+7.62939453125E-5+9.765625E-5+0+-1

No voltage at the load!

 

[Jester]

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

Works, what is the issue?

https://www.electronics-lab.com/blog/?p=10584

 

[yassin.kraouch]

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]

What you have to say about this?
https://www.falstad.com/circuit/#$+...+0+64+0+35+7.62939453125E-5+9.765625E-5+0+-1

No voltage at the load!

Falstad's simulator is excellent, although it is a bit fussy about how wire connections are made. The wire ends must meet exactly.

I revised your wiring to the drain terminal. Current now flows through the load.

https://www.falstad.com/circuit/#$+...+496+272+496+304+0 o+0+64+0+33+10.0+0.2+0+-1

 

[D.A.(Tony)Stewart]

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

 

[Jester]

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]

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).

 

[Jester]

Has anyone ever used a gate driver as a load switch?

For example: https://www.digikey.ca/product-detail/en/ZXGD3003E6TA/ZXGD3003E6TR-ND/1827735

 

[D.A.(Tony)Stewart]

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]

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]

Hi,

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

Klaus