Solved: Increase PWM source current

TKirv1 · ‎08-31-2016

Wondering if it is possible to increase the source current on the Edison's 4 pwm pins. If it makes a difference, I am using the mini breakout board.

Right now I can get about 6-10 mA from the pwm lines, but was hoping to get up to around 50 mA. I am trying to drive brushless motors via ESC's, but the ESC's don't seem to detect the pwm signal with such a low current. The frequency (50-500 hz) and duty cycle (1-2 ms) are all fine, which leads me to believe the current isn't sufficient to be recognized by the ESC. Basically, I NEED MORE ELECTRONS.

I suspect I will need to build some kind of circuit with transistors etc, but wanted to make sure there wasn't a simple way to change some internal configuration on the pwm gpio's to source more current.

I really appreciate any suggestions, or a simple "you need to build an external circuit..". My background is physics and mechanical engineering, but unfortunately not electrical engineering.

Thanks!

idata · ‎09-01-2016

Hi Lit,

I did a little research and I'm afraid to tell you that it isn't possible to increase the PWM source current of the Edison boards internally . Personally, I would recommend you to use an external PWM controller to implement your flight controller, if you want an example that uses Emax simonk 12A you can check this thread: https://communities.intel.com/message/292004# 292004 https://communities.intel.com/message/292004# 292004. The controller used there can help you with your current issues and PWM resolution.

I hope this information helps you.

Regards,

-Leonardo

View solution in original post

idata · ‎09-01-2016

Hi Lit,

I did a little research and I'm afraid to tell you that it isn't possible to increase the PWM source current of the Edison boards internally . Personally, I would recommend you to use an external PWM controller to implement your flight controller, if you want an example that uses Emax simonk 12A you can check this thread: https://communities.intel.com/message/292004# 292004 https://communities.intel.com/message/292004# 292004. The controller used there can help you with your current issues and PWM resolution.

I hope this information helps you.

Regards,

-Leonardo

View solution in original post

TKirv1 · ‎09-02-2016

Thanks for the feedback Leonardo! I was able to make a simple circuit consisting of a transistor and the 5v source which allows me to use the pwm lines to spin the motors. I can do so at 500 hz pwm rate, and get about 75 discrete pulse width values between the min and max speeds of the motor. This may be enough for stable flight but If not I will likely buy an external pwm controller as you suggested.

Cheers

idata · ‎09-02-2016

Hi Thomas,

That's awesome, best wishes for your flight controller and remember that we are here to help you.

Regards,

-Leonardo