Browse Prior Art Database

Light Emitting Diode Stepper Motor Shutoff Control Circuitry

IP.com Disclosure Number: IPCOM000084948D
Original Publication Date: 1976-Feb-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Boinodiris, DK: AUTHOR

Abstract

Fig. 1 shows a stepper motor 10 which is controlled by a computer 11. The stepper motor driver 12 receives low-level electrical pulses from computer 11 and translates such pulses to high-power motor phase driver signals. When the stepper motor phases are stepped, the optical emitter wheel 14 is also stepped by the same angular increment. The light-emitting diode (LED) and phototransistor transducer assembly 15 senses the rotational incremental motion and transmits the two signals (90 degrees out-of-phase) back to the computer 11.

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Light Emitting Diode Stepper Motor Shutoff Control Circuitry

Fig. 1 shows a stepper motor 10 which is controlled by a computer 11. The stepper motor driver 12 receives low-level electrical pulses from computer 11 and translates such pulses to high-power motor phase driver signals. When the stepper motor phases are stepped, the optical emitter wheel 14 is also stepped by the same angular increment. The light-emitting diode (LED) and phototransistor transducer assembly 15 senses the rotational incremental motion and transmits the two signals (90 degrees out-of-phase) back to the computer
11.

The LED and stepper motor shutoff circuitry assures that when the stepper motor 10 is not in use, the drivers 12 are turned off and the LEDs turned down. This avoids excessive power dissipation by the driver circuits 12 with the attendant deleterious effects and extends the life of the LED elements.

Referring to Fig. 2, each of the stepper motor phase signal lines is connected to OR block 16 such that a signal on any one of the lines 17 will fire a retriggerable multivibrator 18. If the single-shot circuit 18 times out without a subsequent signal causing the circuit to be reset, indicating that the drivers have not changed state for this period of time, it is indicative that the stepper motor 10 is not in use and a DEGATE signal is generated.

When AND circuit 19 is satisfied, a down condition occurs on line 20 which causes all four stepper motor driver circuits 12 to be degated...