COMMUNICATION CIRCUIT
1 Assignment
0 Petitions
Accused Products
Abstract
In a communication circuit, an RFIC includes an IO terminal and a control IC includes an IO terminal. A variable capacitance element includes control terminals, a capacitance element with a capacitance value that is determined according to a control voltage, and a resistance voltage divider circuit configured to generate the control voltage by dividing a voltage inputted to the control terminals. One of the RFIC and the control IC supplies control data to the variable capacitance element via a signal line. The variable capacitance element, along with an antenna coil, constitutes an antenna circuit of an LC parallel resonance circuit, and sets a resonant frequency of the antenna circuit to be a predetermined frequency.
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Citations
21 Claims
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1. (canceled)
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2. A communication circuit comprising:
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an RFIC configured to perform modulation and demodulation between a baseband signal and a high-frequency signal; a control IC configured to control the RFIC by receiving and transmitting data including communication data; an antenna coil; and a variable capacitance element configured to change a resonant frequency of an antenna circuit including the antenna coil;
whereinan IO terminal of the RFIC and an IO terminal of the control IC are connected by a signal line, and control terminals of the variable capacitance element are connected to at least a portion of the signal line. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification