Maxim’s MAX4295 Circuit provides Class D motor control

Maxim’s MAX4295 Circuit provides Class D motor control

Class D audio amplifiers provide a dual benefit for battery-powered portable devices (Figure 1). They enhance battery life, and they produce much less power dissipation than do their linear cousins. Those features make Class D amplifiers ideal candidates for controlling speed and direction in small electric motors.

The standard application circuit for a Class D audio amplifier, IC1, requires only slight modifications. In place of the usual audio-signal input is a variable dc voltage that potentiometer R2 generates. Resistor R1 biases the potentiometer to match the input range of IC1. Full-counterclockwise rotation of the potentiometer corresponds to maximum-speed reverse rotation of the motor. Midscale on the potentiometer corresponds to motor off, and full-clockwise rotation of the potentiometer produces maximum-speed forward rotation in the motor. The characteristics of a given motor may allow you to eliminate the amplifier’s output filter, which comprises L1, L2, C1, and C2. But, unless the control circuitry is near the motor, you should include the filter to reduce EMI.

author: John Guy

Please follow and like us:
Pin Share
About mixos

Mike is the founder and editor of, an electronics engineering community/news and project sharing platform. He studied Electronics and Physics and enjoys everything that has moving electrons and fun. His interests lying on solar cells, microcontrollers and switchmode power supplies. Feel free to reach him for feedback, random tips or just to say hello :-)

view all posts by admin
Notify of

Inline Feedbacks
View all comments
Get new posts by email:
Get new posts by email:

Join 97,426 other subscribers