Semiconductor integrated circuit and non-contact electronic device using the same
First Claim
1. A semiconductor integrated circuit, comprising:
- first and second antenna terminals for connection to an antenna;
a power supply circuit for performing rectification of signals between the first and second antenna terminals and voltage control; and
a load modulator for performing modulation of the signals between the first and second antenna terminals,wherein, in a current-voltage characteristic between the first and second antenna terminals in a region where an output voltage of the power supply circuit reaches a predetermined voltage and a voltage suppression operation works, a voltage change slope in a first current region is larger than a voltage change slope in a second current region having a higher current that of the first current region,wherein the power supply circuit has a first voltage controlled circuit and a first voltage detector,wherein the first voltage controlled circuit is provided with a first input terminal and a first output terminal,wherein between the first input terminal and the first output terminal, a first MOS transistor having a first resistor and a second resistor connected in series between a gate and a drain thereof is connected,wherein between a connecting point of the first resistor and the second resistor and a ground terminal, a second MOS transistor whose gate is connected to the first input terminal and a third MOS transistor are connected in series,wherein between the gate of the first MOS transistor and the ground terminal, a fourth MOS transistor whose gate is connected to the first input terminal, a current limiter, and a fifth MOS transistor are connected in series,wherein the gates of the third MOS transistor and the fifth MOS transistor are connected to an output terminal of the first voltage detector,wherein the current limiter controls current flowing between a drain and a source of the fifth MOS transistor,thereby controlling voltage which can be generated in the second resistor,wherein a first input terminal of the first voltage controlled circuit is connected to the first antenna terminal,wherein a first output terminal of the first voltage controlled circuit is connected to a power supply terminal, andwherein the first voltage detector outputs a voltage corresponding to a power supply voltage generated between the power supply terminal and the ground terminal.
4 Assignments
0 Petitions
Accused Products
Abstract
Depending on the power supplied to the non-contact electronic device, the voltage suppression characteristic of the regulator function mounted in a power supply circuit is changed. When the power supplied to the non-contact electronic device is small, the voltage change amount of the voltage between antenna terminals for the current flowing in the antenna is increased, and when the power supplied to the non-contact electronic device is large, the voltage change amount of the voltage between the antenna terminals for the current flowing in the antenna is decreased. By this means, the current change of the entire consumption current for the current change of the load modulator (transmitting circuit) at the time of the long distance communication is increased.
5 Citations
14 Claims
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1. A semiconductor integrated circuit, comprising:
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first and second antenna terminals for connection to an antenna; a power supply circuit for performing rectification of signals between the first and second antenna terminals and voltage control; and a load modulator for performing modulation of the signals between the first and second antenna terminals, wherein, in a current-voltage characteristic between the first and second antenna terminals in a region where an output voltage of the power supply circuit reaches a predetermined voltage and a voltage suppression operation works, a voltage change slope in a first current region is larger than a voltage change slope in a second current region having a higher current that of the first current region, wherein the power supply circuit has a first voltage controlled circuit and a first voltage detector, wherein the first voltage controlled circuit is provided with a first input terminal and a first output terminal, wherein between the first input terminal and the first output terminal, a first MOS transistor having a first resistor and a second resistor connected in series between a gate and a drain thereof is connected, wherein between a connecting point of the first resistor and the second resistor and a ground terminal, a second MOS transistor whose gate is connected to the first input terminal and a third MOS transistor are connected in series, wherein between the gate of the first MOS transistor and the ground terminal, a fourth MOS transistor whose gate is connected to the first input terminal, a current limiter, and a fifth MOS transistor are connected in series, wherein the gates of the third MOS transistor and the fifth MOS transistor are connected to an output terminal of the first voltage detector, wherein the current limiter controls current flowing between a drain and a source of the fifth MOS transistor, thereby controlling voltage which can be generated in the second resistor, wherein a first input terminal of the first voltage controlled circuit is connected to the first antenna terminal, wherein a first output terminal of the first voltage controlled circuit is connected to a power supply terminal, and wherein the first voltage detector outputs a voltage corresponding to a power supply voltage generated between the power supply terminal and the ground terminal. - View Dependent Claims (2, 3, 4, 5, 10, 13, 14)
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6. A semiconductor integrated circuit, comprising:
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first and second antenna terminals to which an antenna is connected; a power supply circuit for performing rectification of signals between the first and second antenna terminals and voltage control; and a load modulator for performing modulation of the signals between the first and second antenna terminals, wherein, in a current-voltage characteristic between the first and second antenna terminals in a region where an output voltage of the power supply circuit reaches a predetermined voltage and a voltage suppression operation works, a voltage change slope in a first current region is larger than a voltage change slope in a second current region having a higher current than that of the first current region, wherein the power supply circuit comprises a third voltage controlled circuit and a first voltage detector, wherein the third voltage controlled circuit is provided with a third input terminal and a third output terminal, wherein between the third input terminal and the third output terminal, a sixth MOS transistor having a third resistor connected between a gate and a drain thereof and a fourth resistor are connected in series, wherein between the third output terminal and the ground terminal, a seventh MOS transistor is connected, wherein between the gate of the sixth MOS transistor and the ground terminal, an eight MOS transistor whose gate is connected to the third input terminal, a current limiter, and a ninth MOS transistor are connected in series, wherein the seventh MOS transistor and the ninth MOS transistor are connected to an output terminal of the first voltage detector, wherein the third input terminal of the third voltage controlled circuit is connected to the first antennal terminal, wherein the third output terminal of the third voltage controlled circuit is connected to a power supply terminal, wherein the current limiter controls a current flowing between a drain and a source of the ninth MOS transistor, thereby controlling a voltage which can be generated in the third resistor, and wherein the first voltage detector outputs a voltage corresponding to a power supply voltage generated between the power supply terminal and the ground terminal. - View Dependent Claims (7, 8, 9)
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11. A semiconductor integrated circuit, comprising:
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first and second antenna terminals to which an antenna is connected; a power supply circuit for performing rectification of signals between the first and second antenna terminals and voltage control; and a load modulator for performing modulation of the signals between the first and second antenna terminals, wherein the power supply circuit is made up of a first voltage controlled circuit and a first voltage detector, wherein the first voltage controlled circuit is provided with an input terminal and an output terminal, wherein a first MOS transistor having a first resistor connected between a gate terminal and a drain terminal is connected between the input terminal and the output terminal, wherein a second MOS transistor is connected between the output terminal and a ground terminal, wherein between a gate terminal of the first MOS transistor and the ground terminal, a third MOS transistor whose gate terminal is connected to the drain terminal of the first MOS transistor, a current limiter, and a fourth MOS transistor are connected in series, wherein a gate terminal of the second MOS transistor and a gate terminal of the fourth MOS transistor are connected to an output terminal of the first voltage detector, wherein the input terminal of the first voltage controlled circuit is connected to the first antenna terminal, wherein a second resistor is connected between the input terminal of the first voltage controlled circuit and a power supply terminal, wherein the current limiter controls current flowing between a drain terminal and a source terminal of the fourth MOS transistor, thereby controlling voltage which can be generated in the first resistor, and wherein the first voltage detector outputs a voltage corresponding to a power supply voltage generated between the power supply terminal and the ground terminal. - View Dependent Claims (12)
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Specification