DIY Small-Power Brushless Motor Driver Board

If you're looking to build a small-power brushless motor driver board, check out this article.

Circuit Board

Testing

Wiring: It works with both 3-wire and 4-wire motors.

Use this hard disk motor for testing, or any other low-power motor.

Power it on. Here, we're measuring the protection output signal, which should normally be a low level.

The motor is running.

During normal operation, the current is minimal and the torque is low. At startup, the current will increase several times.

Measure the speed, as the chip provides a speed output signal.

Around 300 Hz, which translates to a speed of 300 * 20 = 6000 RPM.

There will be some fluctuations.

Duty cycle: 50%...

Use an oscilloscope to check the speed output signal.

A 50% square wave.

Next, check the signals on the UVW phases.

The three drive signals look roughly like this. Without a dual-trace oscilloscope, you won't see phase differences between the drive signals.

This chip can also adjust the speed. The circuit is straightforward, but the chip can be tricky to solder.