Bi-Directional PWM DC Motor Speed Controller -
Bi-Directional PWM DC Motor Speed Controller - CANUK1125
bidirectional DC motor speed controller is based around using a
Microchip PIC Microcontroller at the heart of the circuit controlling a
Full H-Bridge Power stage using four high-power efficient MOSFETs.
The controller allows controlling both the Speed and Direction of a DC
motor using a Pulse-Width-Modulated (PWM) DC voltage with a Duty Cycle
fully adjustable from 0 to 100% (both Positive and Negative DC output).
It can can provide up to a maximum continuous current of about 7A out of
the box, and up to 10A to 15A with the addition of an optional fan
(Model No. FAN-12VDC) and reinforcement of PCB tracks.
Traditionally, switches are used to reverse the polarity of the voltage
applied to a DC motor in order to change the rotation direction.
However, this method requires use of DPDT switches and causes the
voltage applied to the motor to suddenly change from full positive to
full negative. The sudden change while the motor is spinning leads to a
high level of mechanical stress on the motor as well as high current
surges that can cause damage to any electronics in the path.
Using a Full H-Bridge circuit, the solid-state design of this motor
speed controller does not use any mechanical switches and allows the
control of both speed and direction through a single potentiometer. At
its center position, the motor will be forced to stop (i.e. it brakes).
Turning the potentiometer clockwise will cause the motor to start
spinning slowly in the positive direction, with increasing speed up to
the maximum supply voltage at it’s maximum position. Turning the
potentiometer in the counter-clockwise direction will cause the motor to
spin in the reverse direction, again starting slowly up to a maximum
negative supply voltage. Note that in it’s center position, the motor
will actually brake (motor terminals will be grounded) forcing the motor
to stop rather than be in a “floating” or coasting position.
As an added option, the controller allows for selection of two operating
PWM frequencies: 100 Hz or 200 Hz .
• Supply / Load
Voltage: 6 to 24V DC (12V DC Recommended)
• 7 Amps @ 100 Hz Maximum Continuous Current
• Fully adjustable from 0 to 100% Duty Cycle in both directions.
• Frequency: 100Hz or 200 Hz
• PWM Duty Cycle Range: 0% to +/- 100%
• High efficient design using Four High-Power MOSFETs
• Includes two Heatsinks
More common uses
include controlling DC motors in golf carts, buggies, RC cars, robotics,
DC hobby motors, toy DC motors, etc.
See all our motor controllers here
CANUK1125.pdf for complete
instruction manual. Requires
Adobe Acrobat Reader available at