1.5A Full-Bridge PWM Motor Driver Using A4973 Circuit

The Schematic is based on A4973 IC, Designed for bidirectional pulse width modulated (PWM) current control of inductive loads, the A4973 is capable of continuous output currents to ±1.5 A and operating voltages to 50 V. Internal fixed off-time PWM current-control circuitry can be used to regulate the maximum load current to a desired value. The peak load current limit is set by the user’s selection of an input reference voltage and external sensing resistor. The fixed off-time pulse duration is set by a user- selected external RC timing network. Internal circuit protection includes thermal shutdown with hysteresis, transient-suppression diodes, and crossover current protection. Special power-up sequencing is not required. With the ENABLE input held low, the PHASE input controls load current polarity by selecting the appropriate source and sink driver pair. The MODE input determines whether the PWM current-control circuitry operates in a slow current-decay mode (only the selected source driver switching) or in a fast current-decay mode (selected source and sink switching). A user-selectable blanking window prevents false triggering of the PWM current-control circuitry. With the ENABLE input held high, all output drivers are disabled. A sleep mode is provided to reduce power consumption.

Note : – For Higher Motor Supply (12-50V) Input, Omit U2 , in the case logic 5V supply required and possible Motor supply range 12-50V DC 

Note : – Refer data sheet of IC A4973 for R1 and R2 Value

▪ ±1.5 A continuous output current

▪ 12 V DC Supply

▪ 3 V to 5.5 V logic supply voltage

▪ Internal PWM current control

▪ Fast and slow current-decay modes

▪ Sleep (low current consumption) mode

▪ Internal transient-suppression diodes

▪ Internal thermal shutdown circuitry

▪ Crossover current and UVLO protection




Inside IC A4973