Chip for noncontact reader/writer having function for managing power supply

• US 20030141989A1
• Filed: 04/08/2003
• Published: 07/31/2003
• Est. Priority Date: 03/02/2001
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Arisawa, Shigeru, Yamagata, Akihiko
• Granted Patent: US 7,554,383 B2
• Time in Patent Office: Days
• US Class Current: 340/870.01
• CPC Class Codes: G06K 19/0707 the arrangement being capable of collecting energy from external energy sources, e.g. thermocouples, vibration, electromagnetic radiation G06K19/0702 takes precedence
• CPC Class Codes: G06K 19/0712 the arrangement being capable of triggering distinct operating modes or functions dependent on the strength of an energy or interrogation field in the proximity of the record carrier active means for hindering electromagnetic reading or writing G06K19/07336
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 7/10237 the reader and the record carrier being capable of selectively switching between reader and record carrier appearance, e.g. in near field communication [NFC] devices where the NFC device may function as an RFID reader or as an RFID tag
• CPC Class Codes: H02J 5/00 Circuit arrangements for transfer of electric power between ac networks and dc networks H02J3/36 takes precedence
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves

Abstract

The present invention relates to a semiconductor integrated-circuit device capable of seamlessly switching a power source obtained by rectifying a carrier wave and an external power source. The semiconductor integrated-circuit device having a non-contact card function and a non-contact reader/writer function includes a rectifier 131 for rectifying a received carrier wave, a serial regulator 132 for obtaining a predetermined voltage from an output voltage of the rectifier 131, and a power-supply control circuit 138 for turning on/off the voltage from a battery 160. In a case where the output voltage of the battery 160 is equal to or higher than a predetermined voltage, the power-supply control circuit 138 selects the voltage of the battery 160 as power required for operation of an IC 300 when a reader/writer mode signal or a card mode signal is received. On the other hand, when the output voltage of the battery 160 is lower than the predetermined voltage, the power-supply control circuit 138 selects the output voltage from the rectifier 131 as power required for operation of the IC 300. The present invention can be applied to a portable terminal, such as a cellular phone.

Claims

1. A semiconductor integrated-circuit device comprising:

rectifying means for rectifying a received carrier wave;

generation means for generating a first power-supply voltage on the basis of an output by said rectifying means; and

selection means for selecting one of said first power-supply voltage generated by said generation means and a supplied second power-supply voltage as a power-supply voltage required for operation,

wherein said selection means selects said first power-supply voltage as a power-supply voltage required for operation when said second power-supply voltage is equal to or lower than a threshold value, and selects said second power-supply voltage as a power-supply voltage required for operation when said second power-supply voltage is equal to or higher than the threshold value and an instruction to operate in accordance with a predetermined function is given.

2. A semiconductor integrated-circuit device according to claim 1, wherein, in a case where said second power-supply voltage is equal to or higher than the predetermined threshold value, said selection means selects said second power-supply voltage as a power-supply voltage required for operation when an instruction to operate in accordance with a data carrying and processing function for performing communication with an external information processing apparatus is given or when an instruction to operate in accordance with a function for performing communication with an external data carrying and processing medium is given.

3. A semiconductor integrated-circuit device according to claim 2, wherein a function section for realizing a data carrying and processing function, and a function section for performing communication with an external data carrying and processing medium are formed by one chip.

4. A semiconductor integrated-circuit device according to claim 2, further comprising control means, disposed between a connection point of said rectifying means and said generation means and a grounding point, for controlling the switching of a switch in accordance with a signal instructing an operation in accordance with a function for performing communication with an external data carrying and processing medium,

wherein said control means turns off said switch when said signal is supplied, and prevents an inflow of leakage current by said generation means, which occurs when said second power-supply voltage is selected, by said selection means, as a power-supply voltage required for operation.

5. A semiconductor integrated-circuit device according to claim 1, further comprising:

clock extraction means for extracting a first clock on the basis of said carrier wave;

clock generation means for generating a second clock; and

clock selection means for selecting, as a clock used as an operation reference, one of said first clock extracted by said clock extraction means and said second clock generated by said clock generation means,

wherein said clock selection means selects said first clock as a clock used as an operation reference when said first clock is extracted by said clock extraction means, and selects said second clock as a clock used as an operation reference when said first clock is not extracted by said clock extraction means.

6. A portable terminal device comprising a semiconductor integrated-circuit device including:

rectifying means for rectifying a received carrier wave;

generation means for generating a first power-supply voltage on the basis of an output by said rectifying means; and

selection means for selecting one of said first power-supply voltage generated by said generation means and a supplied second power-supply voltage as a power-supply voltage required for operation,

wherein said selection means selects said first power-supply voltage as a power-supply voltage required for operation when said second power-supply voltage is equal to or lower than a threshold value, and selects said second power-supply voltage as a power-supply voltage required for operation when said second power-supply voltage is equal to or higher than the threshold value and an instruction to operate in accordance with a predetermined function is given.

7. A settlement method for performing a settlement, which occurs as a result of a predetermined transaction, with a portable terminal device comprising:

rectifying means for rectifying a received carrier wave;

generation means for generating a first power-supply voltage on the basis of an output by said rectifying means;

selection means for selecting one of said first power-supply voltage generated by said generation means and a supplied second power-supply voltage as a power-supply voltage required for operation; and

storage means for storing money information as a predetermined transaction price, said settlement method comprising;

a communication step of performing communication with said portable terminal device;

a reading step of reading said money information stored in said portable terminal device in the process of said communication step; and

a settlement step of performing a settlement on the basis of said money information read in the process of said reading step.