Thread Starter

Imakeithappen92

Joined Nov 24, 2019
2
Hello all,
Im having trouble switching my mosfet with an arduino within my asymmetrical h bridge. I had it working with an 8 channel relay and switched to a faster isolated switching device, (Dual high power mosfet trigger switch drive module (5v - 36V) 15A). I believe it's because my winding line and source is on the same line, which is reducing the voltage. I was able to get it to switch on my first pcb design then it stopped working (possibly because I damaged the switch mode power supply), but now I got a new switch mode power supply and re did the circuit to make it clear and more drawn out. The second pcb just locks the motor and just melts the source to arduino wires. The arduino is supposed to switch the mosfet on for 3 seconds and then off for 1 second.

 

AlbertHall

Joined Jun 4, 2014
9,642
Why do you have two switches, S1 and S2?
Only S2 is needed, leave S1 as a direct connection to +V and then you don't need D1 either.

In the circuit with MOSFETs, the arduino cannot properly switch Q1, Q3, Q5 but as described above you don't need them. Only Q2, Q4, Q6 and needed.
 

Thread Starter

Imakeithappen92

Joined Nov 24, 2019
2
Why do you have two switches, S1 and S2?
Only S2 is needed, leave S1 as a direct connection to +V and then you don't need D1 either.

In the circuit with MOSFETs, the arduino cannot properly switch Q1, Q3, Q5 but as described above you don't need them. Only Q2, Q4, Q6 and needed.
Why are they in alot of diagrams? What would they be used for? Bi directional flow?
 

jpanhalt

Joined Jan 18, 2008
9,085
Switching "high-side" N-channel mosfets as in Q1, Q3, and Q5 requires that the gate voltage be well above the supply (Vdd) voltage. What gate voltage are your supplying?
 

ScottWang

Joined Aug 23, 2012
6,882
As jpanhalt already pointed out the gates voltages of high sides, normally I will add the gates voltages at least Vdd + 3V.
 

djsfantasi

Joined Apr 11, 2010
6,338
When switching MOSFETs with an Arduino, I typically use a logic level N-channel to switch the P-channel high side MOSFET with a pull-up to Vdd on the P-channel gate. Without this high-side driver, the Arduino cannot switch the MOSFET.
 
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