Control BLDC Motor with 555 Timer: Tutorial & Schematics

[MRClark32493]

I have read that it is possible to control a Brushless DC Motor With A 555 Timer, However I Do Not Know How To Accomplish This, And Have Been Unable To Find Any Schematics For This. Could Someone Please Explain To Me How To Do This And Provide Images Or Schematics. Also, If It Is Not Possible To Accomplish With The 555 Timer, Then Could You Please Direct Me In Another Location To Easily Control A Brushless DC Motor.
Thanks
~Matt

 

[jbord39]

You want to use pulse-width modulation. You can variably change the motors speed by changing the "duty-cycle" of the square wave output from the 555. Here is a simple schematic which will vary the frequency as well as the duty cycle, although that shouldn't make much of a difference (the % high time is really all that matters after about 30Hz).

The optional diode from pins 7 to 2/6 will allow you to get a duty cycle of lower than 55%.

 

[MRClark32493]

Ok, thank you. Now just to make sure that i got this correct,
I supply my voltage to 8
The speed is controlled by a pot between 7/6
And my output is between 3 and ground.
I am fairly new to EE so i would just like to double check everything.
Thanks
~Matt

 

[jbord39]

Yeah that's correct. If your motor needs more than 200mA you might need a transistor.