Claims
- 1. In a driver circuit for a stepping motor having a coil, a stator and a rotor, and receptive of pulse signals from a pulse signal generator to rotationally drive said rotor, the improvement wherein said driver circuit comprises means for detecting a voltage induced in said coil by momentarily connecting said coil to a high impedance element soon after application of a pulse signal from said pulse signal generator, and means for comparing the induced voltage in said coil with a predetermined voltage and providing a corresponding output signal indicative of whether or not said rotor has undergone incremental rotation in response to the applied pulse signal.
- 2. In a driver circuit for a stepping motor having a coil, a stator and a rotor, and receptive of pulse signals from a pulse signal generator to rotationally drive said rotor, the improvement comprising: means switchable between a high impedance loop which includes said coil and a low impedance loop which includes said coil to cause a voltage to be induced in said coil; and detecting means for detecting the induced voltage in said coil.
- 3. A driver circuit for a stepping motor as claimed in claim 2; wherein said switchable means includes means for alternately switching between said high impedance loop and said low impedance loop in response to a detection signal of a relatively higher frequency than said pulse signal from said pulse signal generator.
- 4. A driver circuit for a stepping motor as claimed in claim 3; wherein said switchable means forms said high impedance loop comprised of a high impedance element and said coil after the pulse signal is applied to said stepping motor; and comparing means for comparing a voltage developed across said high impedance element with a predetermined voltage.
- 5. A driver circuit for a stepping motor as claimed in claim 4; wherein said predetermined voltage has a value corresponding to the threshold voltage of a C-MOS logic circuit.
- 6. A driver circuit for a stepping motor as claimed in claim 4; wherein the impedance value of said high impedance element is over five times as high as the direct resistance value of said coil.
- 7. A driver circuit for a stepping motor as claimed in claim 2; wherein said switchable means selectively forms one of two high impedance loops by connecting said high impedance element selectively to either one terminal of said coil or the other terminal of said coil and one of the two loops is selected in response to the energized polarity of said coil.
- 8. A driver circuit for a stepping motor as claimed in claim 7; wherein the two high impedance loops include at least two high impedance elements connected with one terminal and the other terminal of said coil respectively and the other terminals of said two high impedance elements being connected through a gate to a reference voltage level respectively.
- 9. In a circuit for detecting the voltage induced in a coil of a rotary stepping motor of the type having a driving transistor connected to the coil, the improvement comprising: means switchable between a first state wherein a first closed loop is formed which includes the coil and a relatively low impedance element and a second state wherein a second closed loop is formed which includes the coil and a relatively high impedance element; means for switching the switchable means into the first state during the driving of the coil and into the second state thereafter so that a voltage is induced in the coil; and means for detecting the induced voltage in the coil.
- 10. A circuit according to claim 9; including means responsive to the detected induced voltage for providing an output signal indicative of the rotational state of the stepping motor.
Priority Claims (1)
Number |
Date |
Country |
Kind |
52-144651 |
Dec 1977 |
JPX |
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Parent Case Info
This is a divisional of application Ser. No. 966,115, filed Dec. 4, 1978, now U.S. Pat. No. 4,326,278.
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3855781 |
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Divisions (1)
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Number |
Date |
Country |
Parent |
966115 |
Dec 1978 |
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