Microcomputer circuit for attenuating oscillations in a resonant circuit by reversing phase and feeding back resonant circuit output oscillation voltage
First Claim
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1. A microcomputer circuit comprising:
- a central processing unit (CPU) for processing data, for selectively generating an output signal and for generating a suppression signal immediately after ending generation of the output signal;
a resonant circuit;
an output circuit for outputting the output signal from said CPU to said resonant circuit;
attenuation means connected to said output circuit and said CPU, responsive to the suppression signal for attenuating oscillations in said resonant circuit when said CPU generates the suppression signal, and including means for reversing the phase of an oscillation voltage from said resonant circuit and means for feeding back the reversed phase oscillation voltage from said means for reversing to said resonant circuit.
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Abstract
A microcomputer for driving a resonant circuit includes a CPU for processing data, an input circuit for detecting an input signal and for transmitting it to the CPU, an output circuit for outputting an output signal from the CPU to the resonant circuit, and attenuation device for attenuating oscillation in the resonant circuit after the output signal from the CPU is turned off. In a non-contact IC card the resonant circuit is an antenna for sending and receiving data to and from the outside without contact.
44 Citations
6 Claims
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1. A microcomputer circuit comprising:
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a central processing unit (CPU) for processing data, for selectively generating an output signal and for generating a suppression signal immediately after ending generation of the output signal; a resonant circuit; an output circuit for outputting the output signal from said CPU to said resonant circuit; attenuation means connected to said output circuit and said CPU, responsive to the suppression signal for attenuating oscillations in said resonant circuit when said CPU generates the suppression signal, and including means for reversing the phase of an oscillation voltage from said resonant circuit and means for feeding back the reversed phase oscillation voltage from said means for reversing to said resonant circuit. - View Dependent Claims (2, 3)
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4. A non-contact integrated circuit (IC) card comprising:
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antenna means for sending and receiving data; a central processing unit (CPU) for processing data, for selectively generating a transmission signal, and for generating a suppression signal immediately after ending generation of the transmission signal; a reception circuit for detecting a reception signal received by said antenna means and for transmitting the reception signal to said CPU; a transmission circuit for transmitting the transmission signal from said CPU to said antenna means; and attenuation means connected to said transmission circuit and said CPU, responsive to the suppression signal for attenuating oscillations in said antenna means when said CPU generates the suppression signal, and including means for reversing the phase of an oscillation voltage from said antenna means and means for feeding back the reversed phase oscillation voltage from said means for reversing to said antenna means. - View Dependent Claims (5, 6)
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Specification