high amp H-Bridge motor control with a photo resistor

I definitely bit off way more than I can chew with this project. I have gotten a ton of help with the circuit and I think it is done. Now I need some help with the program. My arduino experience is limited to completing the lessons in the starter kit.

First let me show you my circuit that I have built so far:


I have successfully tested the H-Bridge with a 12v battery. I have now added the TC4427 and the Enable mosfet. I would like to test those before I get into anything else.

I am really afraid that I will blow this circuit up.

I think to test this I just need A (Pin 11) to come on high and B (pin 10) to come on low and then the enable mosfet (Q5 Pin 12) to come on low. Then let the motor spin for 20 seconds and then shut it all down. My thought is then I can physically swap A and B to test the other side and then move forward with the final program. I am thinking this through correctly?

Your approach sounds reasonable to me, but you might want to start a bit more slowly, replacing the motor with a resistor of about 1,000 ohms (1K0). Please compute the power dissipation and compare to your resistor before proceeding.

In any case, be prepared to shut off all power rapidly, and wear eye protection.

Good Luck!


Include a fuse in the power line before you do anything else, the resistor instead of a motor during programming is a good idea.

Tom... :)

the resistor instead of a motor during programming is a good idea.

I'd use a 12v auto light bulb so there is visual feedback of what is going on.


I've had a close look at your circuit, the Vdd pin on the TC4427 has to go to the 12V supply, otherwise you will not be able to turn the top P-Ch FETs off. The current config will only let the OUTA and OUTB to go to 5V. This may be enough to turn the N-CH FETs ON, but the P-CH FETs will also still be ON as there will be 7V still between the P-CH Gate and Source.

You need to read the source of your circuit a little more..


Tom..... :)

No decoupling capacitors?