Schematic Reference

Using the LMD18245 full-bridge power amplifier that incorporates all the circuit blocks required to drive and control current in a brushed type DC motor or one phase of a bipolar stepper motor can be designed various motor applications.

The LMD18245 controls the motor current via a fixed off-time chopper technique. An all DMOS H-bridge power stage delivers continuous output currents up to 3A (6A peak) at supply voltages up to 55V. An innovative current sensing method eliminates the power loss associated with a sense resistor in series with the motor.

LMD18245 Bipolar Stepper Motor Circuit Diagram

This LMD18245 circuit application is a power stage of a chopper drive for bipolar stepper motors. The 20 kΩ resistor and 2.2 nF capacitor connected between RC and ground set the off-time at about 48 μs, and the 20 kΩ resistor connected between CS OUT and ground sets the gain at about 200 mA per volt of the threshold for chopping. Digital signals control the thresholds for chopping, the directions of the winding currents, and, by extension, the drive type (full step, half step, etc.). A μprocessor or μcontroller usually provides the digital control signals.

For this bipolar stepper motor driver electronic circuit you will need a 5 volt DC power supply for logic control and a 40 volt DC for powering driver .