Load switch MOSFET

[dark]

That's not telling us what you are driving it with. Makes a big difference.

Driving What ? I gave you the part number its a dedicated chip . It doesnt make any difference if you condition a bridge or an RVDT , please have a look into the datasheet.If it does please point me.

-Adi

 

[duffy]

"With" What are you driving it WITH?

 

[dark]

"With" What are you driving it WITH?

Ah , an MCU . Did I get you right this time Duffy?


-Adi

 

[duffy]

Yes. This circuit would be the kind of thing you want for that. A high logic level will turn on both supplies, a low will turn them both off.

 

[Roff]

Yes. This circuit would be the kind of thing you want for that. A high logic level will turn on both supplies, a low will turn them both off.

The only concern I have is that the circuit dissipates almost 1 Watt, most of it in the 1k resistor. That resistor could be changed to 1.5k, which would reduce the dissipation to less than 600mW, but it's still pretty high. Changing the load switches to MOSFETs (and changing some resistor values) would allow the dissipation to be reduced dramatically, as long as switching speed isn't an issue.
As a side issue, the value of R4 could be at least an order of magnitude larger.

 

[duffy]

Ugh, I didn't even notice that. Here, got rid of the 1 watt resistor. On state resistance is .3 ohms, 50v breakdown, over an amp of on-state goodness in a TO92 or smaller package.

 

[dark]

Thanks duffy the negative MOS schematic is good , Though I was a bit reluctant with the BJT pasrt due to its heavy dissipation.

 

[duffy]

The BJT's didn't have heavy dissipation. A certain resistor did.

 

[dark]

The BJT's didn't have heavy dissipation. A certain resistor did.

I know BJTs dont dissipate , I said regarding the previous schematic that included the BJTs .

 

[bassnut]

Guad, how far can this thread run (despite the fun diversions). Remind me why Boncuks, Ericiaks and my suggestion of a miniature DPDT relay isnt the simplest, smallest, fastest and bestes solution?.