SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE AND IC CARD USING THE SAME
First Claim
1. A semiconductor integrated circuit device comprising:
- an antenna terminal coupled to an antenna;
a first power supply circuit for rectifying and smoothing an AC signal supplied from the antenna to the antenna terminal, thereby obtaining a DC voltage in a first power supply line;
a power supply terminal and a ground terminal to which power is supplied from the outside;
a second power supply circuit comprising a first MOS transistor disposed between the power supply terminal and the first power supply line and a voltage control circuit for controlling a voltage of a gate terminal of the first MOS transistor; and
a substrate potential control circuit for controlling substrate voltage of the first MOS transistor,wherein in the case of using the voltage generated by the first power supply circuit as a power supply, the first MOS transistor is interrupted, thereby isolating the power supply terminal and the first power supply line from each other, andwherein in the case of using a power supply from an external terminal, the power supply control circuit controls the first MOS transistor to suppress voltages supplied from the power supply terminal and the ground terminal to a predetermined voltage and outputs the resultant voltage to the first power supply line.
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Accused Products
Abstract
The present invention enables a power-supply voltage terminal and an internal circuit to be isolated from each other in a noncontact operation without largely increasing a chip area in a semiconductor integrated circuit device for an IC card. A semiconductor integrated circuit device comprises: a first power supply circuit for rectifying and smoothing an AC signal supplied from an antenna to an antenna terminal, thereby obtaining a DC voltage in a first power-supply line; a second power supply circuit comprising a voltage control circuit for controlling gate terminal voltage of a first MOS transistor disposed between a power supply terminal to which power is input from the outside and the first power supply line; a substrate potential control circuit for forming source voltage of the first MOS transistor as a substrate voltage; and a second MOS transistor which makes substrate voltage and gate voltage of the first MOS transistor conductive in the case of using the voltage generated by the first power supply circuit as a power supply, and which makes the substrate voltage and the gate voltage nonconductive in the case of using a power supply from an external terminal.
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Citations
14 Claims
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1. A semiconductor integrated circuit device comprising:
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an antenna terminal coupled to an antenna; a first power supply circuit for rectifying and smoothing an AC signal supplied from the antenna to the antenna terminal, thereby obtaining a DC voltage in a first power supply line; a power supply terminal and a ground terminal to which power is supplied from the outside; a second power supply circuit comprising a first MOS transistor disposed between the power supply terminal and the first power supply line and a voltage control circuit for controlling a voltage of a gate terminal of the first MOS transistor; and a substrate potential control circuit for controlling substrate voltage of the first MOS transistor, wherein in the case of using the voltage generated by the first power supply circuit as a power supply, the first MOS transistor is interrupted, thereby isolating the power supply terminal and the first power supply line from each other, and wherein in the case of using a power supply from an external terminal, the power supply control circuit controls the first MOS transistor to suppress voltages supplied from the power supply terminal and the ground terminal to a predetermined voltage and outputs the resultant voltage to the first power supply line. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A semiconductor integrated circuit device comprising:
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a first power supply circuit for rectifying and smoothing an AC signal supplied from an antenna to an antenna terminal, thereby obtaining a DC voltage in a first power supply line; a second power supply circuit comprising a voltage control circuit for controlling gate terminal voltage of a first MOS transistor disposed between a power supply terminal to which power is input from the outside and the first power supply line; a substrate potential control circuit for forming source voltage of the first MOS transistor as a substrate voltage; and a second MOS transistor which makes substrate voltage and gate voltage of the first MOS transistor conductive in the case of using the voltage generated by the first power supply circuit as a power supply, and which makes the substrate voltage and the gate voltage nonconductive in the case of using a power supply from an external terminal. - View Dependent Claims (11, 12, 13, 14)
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Specification