A Standalone Full Bridge DC Motor Driver

sam.moshiri · October 30, 2022

The Full-Bridge (H-Bridge) is the most popular driver circuit to control brushed DC motors. The main advantage of a full bridge driver is the ability to change the rotation direction of the motor, without manually reversing the supply wires. I’ve already published the Half-bridge and H-bridge driver circuits before; however, I was receiving many requests and comments for a standalone H-Bridge driver to control the DC motors, without using any external board or a controller.

Therefore, I introduced a cheap, compact, and standalone H-Bridge DC motor driver that can be embedded in a variety of mechatronic devices. A cheap ATTiny13 microcontroller controls everything and I used the Arduino IDE to write the microcontroller code. All components, except for the connectors, are SMD.

The motor can be controlled in three modes: Forward, Stop, and Reverse. The user can adjust the rotation speed of the motor separately in the forward or reverse direction, using two panel-mounting potentiometers. The low ON-Resistance of the Mosfets allows you to use this circuit in high currents.

To design the schematic and PCB, I used Altium Designer 22. The fast component search engine (octopart) allowed me to quickly collect the components’ data and generate the BOM as well. To get high-quality fabricated boards, I sent the Gerber files to PCBWay. To test the driver board, I disassembled an electric toy car and used its powerful 775 DC motor (plus the gearbox).

It’s a cool experience, just build one and have fun!

Specifications

Input Voltage (Motor): 8-40VDC

Supply Voltage (Controller): 12VDC

PWM Frequency: 25KHz

Motor Control: Forward-Stop-Reverse

Motor Speed: [0 to 100%] Forward, [0 to 100%] Reverse