Abstract: A closed loop motor system having a motor with a plurality of poles and motor windings associated therewith. The poles define full step motor output positions. The system is of the type that assigns intermediated current values to the motor windings for fine step positions of the motor. The system also comprises a motor output position encoder for generating an integral and fixed number of encoder pulses as the motor moves between any two motor poles. The pulses are equally spaced and at least some corresponding to the fine step positions. An initializing current comprising components for applying full step current values to motor windings for a time interval in which the motor output is assumed to align with a full step position, and components for zeroing the count in the counter and assigning the torque angle value, whereby the encoder does not require alignment relative to the motor.

Abstract: A micro-stepping translator controller for supplying current to a stepping motor having a plurality of windings comprises a power supply for supplying current to all windings and electronic switches for gating current to all windings. Logic means receive inputs comprising a clock input having a frequency being indicative of the micro-stepping rate and a multiplexing pulse. The logic means having digital circuits for outputting over a data bus signals indicative of two quadrants of a stepped periodic function. The signals correspond to different phases of the stepped periodic function during different multiplexing intervals. The logic means has digital circuits for sequentially outputting signals indicative of one of the four quadrants. A digital-to-analog converter is connected to the output data bus for producing an analog signal.

Abstract: A switching amplifier comprises an input terminal connected to a d.c. power supply and an output terminal connected to a load. At least one power transistor is placed in series with the input and output terminals. A PWM circuit outputs a pulse width modulated signal. An isolating driver circuit between the PWM circuit and the control terminal of the power transistor comprises a low voltage power supply; a transformer having primary and secondary windings; an oscillator for outputting a high frequency signal; means for gating the high frequency signal from the oscillator to the primary winding of the transformer in response to the pulse width modulated signal from the PWM circuit; a MOSFET; means for rectifying the voltage in the secondary winding of the transformer and for applying the rectified voltage to the gate of the MOSFET; and switching means for rapidly discharging the gate of the MOSFET when the high frequency signal is no longer gated to the transformer.