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Driving both N and P mosfet with same power supply

iamthevector

Aug 8, 2015
3
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Aug 8, 2015
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I need to drive both n and p mosfet with the same microcontroller and same power supply,

I have a 12v supply, 1 n and 1 p channel mosfet.
When i wanted to drive the N channel i allways used this scheme

-12 to GND , SOURCE to Signal , drain to a pole of the component , +12v to component to switch on and off
if i wanted to use the P channel
+12 to 5V , SOURCE to Signal, drain to a pole of the componente, -12v to component to switch on and off

If i want to use them individually no problem. If i want to use BOTH P and N mosfet with the same power supply
i cannot connect GND to -12 and +12v to 5V or i will blow up the Arduino . How can i solve this? Thanks
 

CDRIVE

Hauling 10' pipe on a Trek Shift3
May 8, 2012
4,960
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May 8, 2012
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4,960
Hello and welcome to EP. We speak the schematic language here, so it's best to post schematics of what you want to do. PCH FETs can be inverted similar to the way we use PNPs with a positive rail supply. When the Gate is brought to GND it will be gated on.

Chris
 

iamthevector

Aug 8, 2015
3
Joined
Aug 8, 2015
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I planned to use the npn indeed, the problem is i need this circuit to be very fast in switching from n and p. Do you think the npn could have any delaying problem?
Here the scheme CDRIVE. As you can see if i use the normal approach the 12v will flow trough the arduino.
 

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CDRIVE

Hauling 10' pipe on a Trek Shift3
May 8, 2012
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Well your schematic is more akin to a PCB layout. It's absolutely painful on old eyes. That said and unless my eyes have totally failed me, I don't see how any of that will work properly. For starters you have the LEDs and the current limiting resistors wired in parallel with the Drain-Source junction of the FETs. The leftmost drawing has NO Vdd either. The PCH FET (middle drawing) has no GND connection.

Please explain fully what exactly you're trying to do and why you think you need a P-CH FET.

Chris
 

AnalogKid

Jun 10, 2015
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An NPN transistor switch such as a 2N4401 will delay the signal by less than 1 us, probably closer to 200 ns. If you need less delay than this, you can use any inverting CMOS logic gate. If you don't want to add a 14 pin package for only one gate, some CMOS functions are available in single-gate SOT23 package.

ak
 

BobK

Jan 5, 2010
7,682
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Jan 5, 2010
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7,682
Another option is a high and low side MOSFET driver, which allows you to use an N channel on the high side.

Bob
 
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