Allegro MicroSystems Europe (www.allegromicro.com) has introduced a new programmable stepper motor driver IC that offers improved diagnostics and programmability as well as micro-stepping capability.

A microstepping motor driver, the flexible A4979 provides a single-chip solution for operating bipolar stepper motors in sixteenth-, quarter-, half- and full-step modes at currents up to 1.5A and voltages up to 50V. For easy operation, the A4979 offers a built-in translator.

Using digital timing, the A4979 eliminates the need for external timing components while utilizing a serial port (SPI) for reading back diagnostics information and programming operating parameters. This allows the device to be controlled via the SPI-compatible serial interface or by simple step and direction inputs.

Its phase current tables can be programmed through serial interface to create distinct micro-stepping current profiles that will improve the performance of the motor for specific applications. Additionally, its current regulator can also be programmed to operate in fixed frequency pulse-width modulation or fixed off-time modes, with various decay modes available to optimize step accuracy and reduce audible motor noise.

Circuit protection of the A4979 includes cross-conduction when switching between low-side and high-side drives. Allegro has also integrated the device with mixed decay to enhance low load current accuracy, while its outputs are protected from short circuits. Other protection features of the A4979 include stall detection and hot and cold thermal warnings, under-voltage lockout and over-temperature shutdown.

The company said that the new device is aimed at the industrial, office automation and consumer markets.