Semiconductor device and driving method thereof
First Claim
1. A semiconductor device comprising:
- an antenna circuit;
a converter circuit which converts an AC voltage to a DC voltage through rectification;
a comparator circuit;
a reference voltage source;
a switch element electrically connected to the comparator circuit and the ground; and
a capacitor electrically connected to the antenna circuit and the switch element, wherein the antenna circuit is electrically connected to the converter circuit, and, wherein the comparator circuit compares an output voltage of the reference voltage source with an output voltage of the converter circuit.
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Accused Products
Abstract
There has been a problem in battryless RFID chips that a high voltage AC signal is generated when an antenna is exposed to a high electromagnetic field, and a DC voltage that is obtained through rectification of the AC signal becomes a high voltage accordingly. As a result, heat generation of a logic circuit and a clock generator circuit or element break down occur. The invention takes the following measures: a DC voltage generated through rectification of an AC signal is compared with a reference voltage in a comparator circuit, and a switch element is turned ON when the DC voltage becomes higher so as to add capacitance to an antenna circuit. Accordingly, resonance point of an antenna changes which in turn attenuates an AC signal generated in the antenna circuit, thereby suppressing a DC voltage.
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Citations
69 Claims
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1. A semiconductor device comprising:
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an antenna circuit;
a converter circuit which converts an AC voltage to a DC voltage through rectification;
a comparator circuit;
a reference voltage source;
a switch element electrically connected to the comparator circuit and the ground; and
a capacitor electrically connected to the antenna circuit and the switch element, wherein the antenna circuit is electrically connected to the converter circuit, and, wherein the comparator circuit compares an output voltage of the reference voltage source with an output voltage of the converter circuit. - View Dependent Claims (7, 13, 19, 25, 31, 37, 43, 49, 55, 61)
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2. A semiconductor device comprising:
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an antenna circuit;
a converter circuit which converts an AC voltage to a DC voltage through rectification;
a plurality of comparator circuits;
a plurality of reference voltage sources;
a plurality of switch elements each of which is electrically connected to the comparator circuit and the ground; and
,a plurality of capacitors each of which is electrically connected to the antenna circuit and the respective switch elements, wherein the antenna circuit is electrically connected to the converter circuit, and, wherein the plurality of comparator circuits compare output voltages of the respective reference voltage sources with an output voltage of the converter circuit, respectively. - View Dependent Claims (8, 14, 20, 26, 32, 38, 44, 50, 56, 62)
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3. A semiconductor device comprising:
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a first antenna circuit;
a second antenna circuit;
a first converter circuit which converts an AC voltage to a DC voltage through rectification;
a second converter circuit which converts an AC voltage to a DC voltage through rectification;
a comparator circuit;
a switch element electrically connected to the comparator circuit and the ground; and
a capacitor electrically connected to the first antenna circuit and the switch element, wherein the first and the second antenna circuits are electrically connected to the first and the second converter circuits, respectively, and, wherein a comparator circuit compares an output voltage of the first converter circuit with an output voltage of the second converter circuit. - View Dependent Claims (9, 15, 21, 27, 33, 39, 45, 51, 57, 63)
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4. A semiconductor device comprising:
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an antenna circuit;
a converter circuit which converts an AC voltage to a DC voltage through rectification;
a comparator circuit;
a reference voltage source;
a monitor circuit electrically connected to the converter circuit and the comparator circuit;
a switch element electrically connected to the comparator circuit and the ground; and
a capacitor electrically connected to the antenna circuit and the switch element, wherein the antenna circuit is electrically connected to the converter circuit, and wherein the comparator circuit compares an output voltage of the reference voltage source with an output voltage of the monitor circuit. - View Dependent Claims (10, 16, 22, 28, 34, 40, 46, 52, 58, 64)
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5. A semiconductor device comprising:
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an antenna circuit;
a converter circuit which converts an AC voltage to a DC voltage through rectification;
a plurality of comparator circuits;
a plurality of reference voltage sources;
a monitor circuit electrically connected to the converter circuit and the comparator circuit;
a plurality of switch elements each of which is electrically connected to the comparator circuit and the ground; and
,a plurality of capacitors each of which is electrically connected to the antenna circuit and the respective switch elements, wherein the antenna circuit is electrically connected to the converter circuit, and wherein the plurality of comparator circuits compare output voltages of the respective reference voltage sources with an output voltage of monitor circuit, respectively. - View Dependent Claims (11, 17, 23, 29, 35, 41, 47, 53, 59, 65)
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6. A semiconductor device comprising:
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a first antenna circuit;
a second antenna circuit;
a first converter circuit which converts an AC voltage to a DC voltage through rectification;
a second converter circuit which converts an AC voltage to a DC voltage through rectification;
a comparator circuit;
a first monitor circuit electrically connected to the first converter circuit and the comparator circuit;
a second monitor circuit electrically connected to the second converter circuit and the comparator circuit;
a switch element electrically connected to the comparator circuit and the ground; and
a capacitor electrically connected to the first antenna circuit and the switch element, wherein the first and the second antenna circuits are electrically connected to the first and the second converter circuits, respectively, and, wherein a comparator circuit compares an output voltage of the first monitor circuit with an output voltage of the second monitor circuit. - View Dependent Claims (12, 18, 24, 30, 36, 42, 48, 54, 60, 66)
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67. A driving method of a semiconductor device, comprising the steps of:
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converting an AC voltage generated in an antenna circuit to a DC voltage through rectification;
comparing the DC voltage with a reference voltage;
connecting a capacitor in parallel to the antenna circuit when the DC voltage reaches higher than the reference voltage;
attenuating the AC voltage generated in the antenna circuit; and
converting the attenuated AC voltage to a DC voltage through rectification.
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68. A driving method of a semiconductor device, comprising the steps of:
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converting an AC voltage generated in an antenna circuit to a DC voltage through rectification;
comparing the DC voltage with a plurality of reference voltages;
connecting a capacitor being corresponding to the reference voltage at higher level than the DC voltage in parallel to the antenna circuit when the DC voltage reaches higher than any one of the reference voltages;
attenuating the AC voltage generated in the antenna circuit; and
converting the attenuated AC voltage to a DC voltage through rectification.
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69. A driving method of a semiconductor device, comprising the steps of:
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converting an AC voltage generated in a first antenna circuit to a first DC voltage through rectification;
converting an AC voltage generated in a second antenna circuit to a second DC voltage through rectification;
comparing the first DC voltage with a the second DC voltage;
connecting a capacitor in parallel to the antenna circuit when the first DC voltage reaches higher than the second DC voltage;
attenuating the AC voltage generated in the first antenna circuit; and
converting the attenuated AC voltage to a DC voltage through rectification.
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Specification