Micro-Step Driver for Bipolar Step Motor

Overview

The device is designed to use parallel ports in order to connect a bipolar step motor to a personal computer.

Details

The circuit is allowed to manage motors up to 3A for phase and is optically isolated from the PC for safety reasons. Also, up to 6 motors can be connected to a single PC parallel port through the digital interface. The ability to implement the micro-step technique and to multiply up to 64 times the motor real steps number are the interesting aspects of this circuit. In the order of fractions of rpm, this function is particularly useful when the spin speed is very low. To test the operation of a motor under Windows, a short software was included along with a mini-software for DOS and Linux.

Two sections divide the hardware of the device which include power section built around LMD18245 and digital section. To digitally create the current that must be sent to the load in 16 steps, the LMD18245 includes logic. The value of resistance as well as the four digital inputs provide the value of current. The maximum power supply is 50V while the maximum current is 3A.