Semiconductor integrated circuit device, and non-contact type IC card and portable information terminal using the semiconductor integrated circuit device

1. A semiconductor integrated circuit device comprising:

an antenna terminal which is connected to an antenna;

a power source circuit which has a rectifier/smoothing circuit which obtains a DC voltage by rectifying and smoothing an AC signal which is supplied to the antenna terminal from the antenna, and a shunt regulator and a series regulator which stabilize the DC voltage; and

an internal circuit which is operated upon the supply of the DC voltage from the power source circuit,

wherein the series regulator performs a voltage stabilizing operation and the shunt regulator stops a voltage stabilizing operation in a stage that a signal is transmitted to a reader/writer, and

wherein the shunt regulator performs a voltage stabilizing operation and the series regulator stops a voltage stabilizing operation in a stage that inner processing is performed.

2. A semiconductor integrated circuit device according to claim 1 ,

wherein the semiconductor integrated circuit device further includes a load modulator which is connected to the antenna terminals, and

wherein the signal is transmitted to the reader/writer in response to the presence or non-presence of an electric current which flows in the load modulator.

3. An IC card comprising:

a coil which constitutes an antenna; and

a semiconductor integrated circuit device,

wherein the semiconductor integrated circuit device comprises:

an antenna terminal which is connected to the antenna;

a power source circuit which includes a rectifier/smoothing circuit which outputs a power source voltage by rectifying and smoothing an AC signal which is inputted to the antenna terminal, and a regulator which stabilizes a voltage of the power source voltage and outputs the stabilized power source voltage to a power source terminal; and

an internal circuit which includes a control circuit which generates a control signal which controls a voltage stabilizing operation of the power source circuit,

wherein the power source circuit is controlled in response to the control signal such that a voltage between the rectifier/smoothing circuit and the power source terminal is changed in a stage that a signal is transmitted to a reader/writer and is controlled in response to the control signal such that a current which flows between the power source terminal and a ground terminal is changed in a stage that inner processing is performed.

4. An IC card according to claim 3 , wherein the antenna terminal is constituted of two terminals for inputting the AC signal from the antenna, and the internal circuit includes a load modulator which is connected between one terminal out of two terminals and the ground terminal, and the signal is transmitted to the reader/writer in response to the presence or non-presence of an electric current which flows in the load modulator.

5. An IC card according to claim 3 , wherein the regulator is operated as a series regulator in the stage that the signal is transmitted to the reader/writer, and is operated as a shunt regulator in the stage that the inner processing is performed.

6. An IC card according to claim 3 ,

wherein the regulator is constituted of a shunt regulator and a series regulator, and

wherein the series regulator performs a voltage stabilizing operation in response to the control signal in the stage that the signal is transmitted to the reader/writer, and the shunt regulator performs a voltage stabilizing operation in response to the control signal in the stage that the inner processing is performed.

7. A portable information terminal comprising:

a data processing circuit which processes data;

a display device which displays data which is inputted to and outputted from the data processing circuit;

an input device which inputs data to the data processing device; and

an IC card which includes a coil which constitutes an antenna and a semiconductor integrated circuit device, and is electrically connected with the display device,

wherein the semiconductor integrated circuit device comprises:

an antenna terminal which is connected to the antenna;

a power source circuit which includes a rectifier/smoothing circuit which outputs a power source voltage by rectifying and smoothing an AC signal which is inputted to the antenna terminal, and a regulator which stabilizes a voltage of the power source voltage and outputs the stabilized power source voltage to a power source terminal; and

an internal circuit which includes a control circuit which controls a voltage stabilizing operation of the power source circuit,

wherein the power source circuit is controlled by the control circuit such that a voltage between the rectifier/smoothing circuit and the power source terminal is changed in a stage that a signal is transmitted to a reader/writer and is controlled by the control circuit such that a current which flows between the power source terminal and a ground terminal is changed in a stage that inner processing is performed, and

wherein data which the IC card possesses is displayed on the display device.

8. A portable information terminal according to claim 7 , wherein the antenna terminal is constituted of two terminals for inputting the AC signal from the antenna, and the internal circuit includes a load modulator which is connected between one terminal out of two terminals and the ground terminal, and the signal is transmitted to the reader/writer in response to the presence or non-presence of an electric current which flows in the load modulator.

9. A portable information terminal according to claim 8 , wherein the portable information terminal is a mobile phone which further includes a transmission and reception circuit for performing communication using voice or data.

10. A portable information terminal according to claim 7 , wherein the regulator is operated as a series regulator in the stage that the signal is transmitted to the reader/writer, and is operated as a shunt regulator in the stage that the inner processing is performed.

11. A portable information terminal according to claim 10 , wherein the portable information terminal is a mobile phone which further includes a transmission and reception circuit for performing communication using voice or data.

12. A portable information terminal according to claim 7 ,

wherein the regulator is constituted of a shunt regulator and a series regulator, and

wherein the series regulator performs a voltage stabilizing operation in the stage that the signal is transmitted to the reader/writer, and the shunt regulator performs a voltage stabilizing operation in the stage that the inner processing is performed.

13. A portable information terminal according to claim 12 , wherein the portable information terminal is a mobile phone which further includes a transmission and reception circuit for performing communication using voice or data.

14. A portable information terminal according to claim 7 , wherein the portable information terminal is a mobile phone which further includes a transmission and reception circuit for performing communication using voice or data.