A4992: Automotive Stepper Driver

The A4992 is a flexible microstepping motor driver with integrated phase current control and a built-in translator for easy operation. It is a single chip solution designed to operate bipolar stepper motors in full, half, quarter, eighth, and sixteenth step modes, at up to 28 V. At power-on the A4992 is configured to drive most small stepper motors with simple step and direction inputs.

The current regulator operates with fixed frequency PWM. It uses adaptive mixed current decay to reduce audible motor noise and increase step accuracy.

The current in each phase of the motor is controlled through a DMOS full bridge using synchronous rectification to improve power dissipation. Internal circuits and timers prevent crossconduction and shoot-through when switching between high-side and low-side drives.

The outputs are protected from short circuits. Features for low load current and stalled rotor detection are included. Chip level protection includes hot thermal warning, overtemperature shutdown, and overvoltage and undervoltage lockout.

An optional serial interface mode, using the STEP, DIR, and MS inputs, can be used to configure several motor control parameters and diagnostics.

The A4992 is supplied in a 20-pin TSSOP power package with an exposed thermal pad (package type LP). This package is lead (Pb) free with 100% matte tin lead frame plating.

Applications:

• Automotive stepper motors
• Engine management
• Headlamp positioning