Driver circuit for electro-mechanical transducer
First Claim
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1. A driver circuit for an electro-mechanical transducer of an electronic timepiece having an oscillator circuit providing a relatively high frequency signal and a frequency divider to divide down the relatively high frequency signal to provide a low frequency signal, said driver circuit comprising:
- a driving coil for driving said electro-mechanical transducer;
means for detecting an induced voltage of said driving coil and producingan output signal when said induced voltage decreases below a predetermined value; and
a pulse width change-over circuit connected to said frequency divider and responsive to said low frequency signal to provide first driving pulses of a first pulse width to energize said driving coil when said induced voltage is above said predetermined value;
said pulse width change-over circuit including means for providing second driving pulses of a second pulse width larger than said first pulse width to energize said driving coil in response to said output signal to compensate for a decrease in said induced voltage below said predetermined value.
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Abstract
An electro-mechanical transducer driver circuit for an electronic timepiece characterized in that the pulse width of a driving pulse which drives an electro-mechanical transducer is controlled in a step-wise manner by the induced voltage of a driving coil.
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Citations
7 Claims
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1. A driver circuit for an electro-mechanical transducer of an electronic timepiece having an oscillator circuit providing a relatively high frequency signal and a frequency divider to divide down the relatively high frequency signal to provide a low frequency signal, said driver circuit comprising:
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a driving coil for driving said electro-mechanical transducer; means for detecting an induced voltage of said driving coil and producing an output signal when said induced voltage decreases below a predetermined value; and a pulse width change-over circuit connected to said frequency divider and responsive to said low frequency signal to provide first driving pulses of a first pulse width to energize said driving coil when said induced voltage is above said predetermined value; said pulse width change-over circuit including means for providing second driving pulses of a second pulse width larger than said first pulse width to energize said driving coil in response to said output signal to compensate for a decrease in said induced voltage below said predetermined value. - View Dependent Claims (2, 3, 4)
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5. A driver circuit for an electro-mechanical transducer of an electronic timepiece powered by a battery and having an oscillator circuit providing a relatively high frequency signal, and a frequency divider to divide down the relatively high frequency signal to provide first and second low frequency signals, said driver circuit comprising:
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a driving coil to drive said electro-mechanical transducer; a voltage detection circuit adapted to be connected to said battery for detecting an output voltage thereof to provide an output signal when said output voltage decreases below a predetermined level; a waveform shaping circuit responsive to said first low frequency signal to provide first driving pulses of a first pulse width to energize said driving coil when said output voltage is above said predetermined value; and said waveform shaping circuit including means for providing second driving pulses of a second pulse width larger than said first pulse width to energize said driving coil in response to said output signal and said second low frequency signal to compensate for a decrease in said battery below said predetermined value. - View Dependent Claims (6, 7)
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Specification