Minh Que Tu

US Patent:

48292222, May 9, 1989

Filed:

Aug 19, 1987

Appl. No.:

7/087138

Inventors:

Richard A. Hallenbeck - Wilton CT
Minh Q. Tu - Bethel CT

Assignee:

Pitney Bowes Inc. - Stamford CT

International Classification:

H02P 800

US Classification:

318696

Abstract:

A driver circuit is under the control of a microprocessor and in communication with a stepper motor. The stepper motor is in driving communication with a mechanism. A power source having a first and second voltage level is in communication with the stepper motor such that the first voltage level is in direct communication with the power terminal of the stepper motor. The second voltage level can be selectively applied to the power terminal of the stepper motor upon instruction of the microprocessor to a gate circuit of the driver circuit. The driver circuit also includes a gating amplifier having a plurality of stages, each stage in communication with a respective one of the stepping terminals of said stepper motor. A coupling circuit means is provided for receiving a series of step commands from said microprocessor and turning "ON" or "OFF" a respective stage of said gating amplifier in accordance with a respective step command in the form of a binary set number.