Pitney Bowes Inc.

Mark E Sasso

Luu T Pham

Yanqing Li

The invention is a low-cost stepper motor drive system comprising a microstepping motor and a logic circuit. The logic circuit includes two integrated circuits for controlling one or more phases of the microstepping motor. Each one of the integrated circuits is a motor driver capable of producing up to sixteen microsteps per full step. Further, each one of the integrated circuits takes a set of analog/digital bits and a phase bit as input. Additionally, within the logic circuit, there is included a microcontroller for controlling the microstepping motor. The microcontroller comprises six control bits, which direct the controller in outputting a set of step sequences to the integrated circuits. The microcontroller can run in one of two program modes: a stand-alone mode which utilizes two profile bits to select one of a set of four slew velocities and which will accelerate the microstepping motor then slew at a preprogrammed velocity as selected by the two profile bits; and, a pulse controlled mode, wherein the motor velocity of the microstepping motor is directly related to an input pulse signal wherein each time the microcontroller receives the input pulse signal the microcontroller will output a step to the integrated circuits. The logic circuit further includes a driver circuit for driving current through each one of the motor phases, and two snubber circuits operatively located between the outputs of each one of the motor phases of each integrated circuit for stabilizing the voltage level of the logic circuit.

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Naugatuck, CT, United States of America

Mark E Sasso