SimpleFoc with IR2104 not working

Hi. I build this driver from here : Sensorless BLDC motor control with Arduino - DIY ESC - Simple Circuit
The problem was that only pin 9 gave me a pwm output, the other pins showed nothing on the oscilloscop.
So i gave up and started with simplefoc. I used the same outputs like the driver above, the code is Open loop motor control example (with modified pins)
The arduino pro mini gives the 3 pwm on those respective pins but only 1.25V per pin from GND.
and i think the minim input voltage for the ir2104 is 3.3V.
The driver does nothing.
SD pin is connected to be active high (5V).
Is there a way to boost the voltage?

Hi @Vlad_Daniel ,

How are you measuring the voltages on the PWM pins? You would need an oscilloscope to look at them… could you send a picture.

If the output voltage on the PWM is really only a 1.25V square wave, then there is something electrically wrong with the setup. The PWM should be a 5V square wave.

What happens if you disconnect the Pro-Mini from the motor driver, and just look at the PWM with no driver attached? Is it a 5V wave in this case?

i only measure with a multimeter from the pwn pin to ground but the oscilloscop does give me peak to peak voltage of 5V.
I only suspect that the driver is not turn on.
I think SD is active low. but i tried low and high but the driver does not turn on.
plus i saw on the internet several schematics with the SD pin to the 12V rail.


You can’t measure the PWM signal reliably with a multimeter. If it’s 5V on the oscilloscope then it is correct, in terms of voltage.

You can check this with the oscilloscope too :slight_smile:

SD = SHUTDOWN is active low. So the opposite of shutdown (let’s call it “ENABLE”) is active-high.

5V should be enough on the SD pin to switch it on, according to the datasheet.

Yes, you can apply up to VCC to the logic pins, but 3V is enough to activate them.

Could you solve your issues?

thanx for the reply.Nope i didnt make nothing work not IR2104 or any other ir chip like ir2113 or ir2110.
I have a simplefoc mini but i dont have a bldc motor with encoder so i just used it in open loop but the motor just buzz and its not turning.
Btw there is no output (square wave ) on oscilloscope on the ir2104 or any other IR.There is voltage but thats all( on one ouput 11V)
Maybe i have faulty IRs.
I really want to verify them but i dont know how.
The reason i think have faulty because i bought 10 pcs of IR2101 and they get hot when connected with only power.
I also bought 5 pcs of IR2153 for the fun of it, but one of them was defective so i guess i have to find a different supplier.