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High-Performance Power ICs and Hall-Effect Sensors
Full-Bridge PWM Microstepper for Digital Control of Bipolar Stepper Motors
Editorial Contact:
Liz Gulachenski, Director, Marketing Communications
Phone: (508)854-5359
October, 1997 - Allegro MicroSystems Inc. announces the release of the A3955SB and A3955SLB, full-bridge PWM, 50 V, ±1.5 A motor drivers intended for use in bipolar stepper systems which require digital microstepping control. The A3955 incorporates a 3-bit digital-to-analog converter to provide 8-step control of 2-phase bipolar stepper motors. Microstepping provides for increased step resolution, and reduces torque variations and resonance problems at low speed.
The A3955 PWM current control can be optimized by selecting either slow (two quadrant) current-decay, fast (four quadrant) current-decay, or mixed current-decay modes. In the mixed decay mode, the user selects the ratio of fast and slow decay. This optimization minimizes the load ripple current, and hence motor heating, while maintaining good current regulation.
Internal circuit protection includes thermal shutdown, transient-suppression diodes, and under-voltage lockout circuitry that prevents the need for special power-up sequencing. The A3955 is offered in both 16-pin power DIP as well as 16-lead power SOIC.
Allegro MicroSystems, Inc. serves major automotive, industrial and computer peripheral customers with it's growing line of mixed-signal (analog/digital) products. Allegro specializes in developing system-level solutions that integrate proprietary combinations of bipolar, CMOS and DMOS structures into a single monolithic integrated circuit.
Allegro Microsystems, Inc. serves major automotive, industrial and computer peripheral customers with its growing line of mixed-signal analog/digital)products. Allegro specializes in developing system-level solutions that integrate proprietary combinations of bipolar, CMOS and DMOS structures into a single, monolithic integrated circuit.