Problem in the control of the pump 12V :in the motor driver!!!

[Mr HG]

I designed this circuit hacheur.jpg and I will use this method to control my pump 12V (in the place of an other circuit which I posted two weeks ago...) from the STM32 microcontroller which give a PWM 3.3V in the input.

The problem now is : If I put the supply +12V, the IR2110 become very hot and it is destructed!!! the IRF350 is also very hot and I haven't the PWM (12V) in the output !!!!

Can you help me and tell me what's the problem and what can I modify ???

 

[KMoffett]

That MOSFET has a Vgs of between 2V and 4V. That's the turn-on "threshold", not the saturation level. The 3.3V (probably actually lower) PWM is only partially turning it on, so you are dropping a lot of voltage across the MOSFET. You need a "logic level" MOSFET.

Ken

 

[Misterbenn]

Or a driver designed for a power FET

 

[dr pepper]

I f I read the schematic right the op is only driving the opto led with 3.3, everything else driving the fet is 12v.

If the fet is hot without any pwm at the i/p it looks like it isnt switching off for some reason, maybe this is a layout issue, driver ics can go into oscillation if the layout isnt very good or there isnt enough decoupling.

Also 100r on the fet gate seems a little high, how did you get this value?, 10r seems more likely, check the 1n4148, if there has been bad ground bounce maybe you fried it, a uf4001 might be a better choice, also might be worth putting a similar diode across the motor connections to soak up bemf at the source, even if the fet has a diode built in.

 

[Mr HG]

Hello,

I solved my problem. The pump must be connected in parallel with the free wheeling diode BYW29.

Thank you

 

[dr pepper]

Glad we could help.
If only I had a quid for every time noise catched me out.

 

[perla]

hi,
I'm new to this forum and I have a problem which is very urgent for me to find a solution.

I realized this circuit and I have the same problem as MR HG.
can you help me please.
thank you.

 

[alec_t]

I realized this circuit

How? Breadboard? Perf-board? Pcb?
Circuit layout is a possible cause. The conducting path between IC8 and the FET Q1 is critical and should be as physically short as possible. A star ground system is advisable.

 

[4pyros]

hi,
I'm new to this forum and I have a problem which is very urgent for me to find a solution.

I realized this circuit and I have the same problem as MR HG.
can you help me please.
thank you.

This is a vary old thread, you should have started a new one.
It seems to me that the FET is connected across the supply shorting it out.
The pump needs to be in series with the FET, not in parallel with the FET or that extra diode.
Get rid of D1, and move your LED down to the other end of motor by the FET.

 

[perla]

thanks a lot