Dual DMOS Full-Bridge Microstepping PWM Motor Driver:Designed for pulse-width modulated (PWM) current control
of bipolar microstepping stepper motors, the A3972 is capable
of continuous output currents to ±1.5 A and operating voltages
to 50 V. Internal fixed off-time PWM current-control timing
circuitry can be programmed via a serial interface to operate
in slow, fast, and mixed current-decay modes.
The desired load-current level is set via the serial port with
two 6-bit linear DACs in conjunction with a reference voltage.
The six bits of control allow maximum flexibility in torque
control for a variety of step methods, from microstepping to
full-step drive. Load current is set in 1.56% increments of the
maximum value.
Synchronous rectification circuitry allows the load current
to flow through the low RDS(on) of the DMOS output driver
during the current decay. This feature will eliminate the
need for external clamp diodes in most applications, saving
cost and external component count, while minimizing power
dissipation.