Passive type RFID semiconductor device, IC tag, and control method

• US 20060175420A1
• Filed: 02/08/2006
• Published: 08/10/2006
• Est. Priority Date: 02/09/2005
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: Satou, Koutarou
• Granted Patent: US 7,806,332 B2
• Time in Patent Office: Days
• US Class Current: 235/492
• CPC Class Codes: G06K 19/0701 at least one of the integrated circuit chips comprising an arrangement for power management
• 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

Abstract

To provide a semiconductor device capable of securely executing a reading operation to improve a reliability of read data, an IC tag including the semiconductor device, and a control method for the IC tag. A semiconductor device according to an embodiment of the present invention includes: a power supply voltage generating circuit for generating a power supply voltage based on a received radio signal; a power supply voltage generating circuit for detecting the power supply voltage; a memory area for storing predetermined data; a reading/writing circuit using different operation voltages for reading data from the memory area and writing data to the memory area; and a control circuit for executing a data reading operation for the memory area based on a detected power supply voltage.

Claims

1. A passive type RFID semiconductor device, comprising:

a power supply voltage generating unit for generating a power supply voltage based on a received radio signal;

a voltage detecting unit for detecting the generated power supply voltage;

a storage unit for storing predetermined data;

a reading/writing unit using different operation voltages for reading data from the storage unit and writing data to the storage unit; and

a control unit for executing a data reading operation for the storage unit based on the power supply voltage detected by the voltage detecting unit.

2. The passive type RFID semiconductor device according to claim 1, wherein the control unit executes the data reading operation based on the power supply voltage detected by the voltage detecting unit in response to a command received from a reader/writer.

3. The passive type RFID semiconductor device according to claim 2, wherein the data reading operation includes a processing of transmitting data read from the storage unit.

4. The passive type RFID semiconductor device according to claim 2, wherein the data reading operation includes a processing of transmitting a detection result from the voltage detecting unit.

5. The passive type RFID semiconductor device according to claim 1, wherein the control unit executes the data reading operation if the power supply voltage detected by the voltage detecting unit is a predetermined value or larger.

6. The passive type RFID semiconductor device according to claim 5, wherein the predetermined value is a voltage value at which the data reading operation can be executed.

7. The passive type RFID semiconductor device according to claim 1, wherein the storage unit is a nonvolatile memory.

8. The passive type RFID semiconductor device according to claim 1, further comprising a register unit for temporarily storing the detection result from the voltage detecting unit.

9. The passive type RFID semiconductor device according to claim 8, wherein the register unit further stores a tag ID.

10. An IC tag, comprising:

an antenna for transmitting/receiving radio waves to/from a reader/writer; and

a semiconductor device connected with the antenna and including;

a power supply voltage generating unit for generating a power supply voltage based on a received radio signal;

a voltage detecting unit for detecting the generated power supply voltage;

a storage unit for storing predetermined data;

a reading/writing unit using different operation voltages for reading data from the storage unit and writing data to the storage unit; and

a control unit for executing a data reading operation for the storage unit based on the power supply voltage detected by the voltage detecting unit.

11. The IC tag according to claim 10, wherein the control unit executes the data reading operation if the power supply voltage detected by the voltage detecting unit is a predetermined value or larger.

12. The IC tag according to claim 11, wherein the predetermined value is a voltage value at which the data reading operation can be executed.

13. A control method for controlling a reading operation for an IC tag including a storage unit for storing predetermined data, and a reading/writing unit using different operation voltages for reading data from the storage unit and writing data to the storage unit, includes processings executed in the IC tag, the processings including:

generating a power supply voltage based on a radio signal received from a reader/writer;

detecting the generated power supply voltage; and

executing a data reading operation for the storage unit based on the detected power supply voltage.

14. The control method according to claim 13, wherein the data reading operation executed in the IC tag includes a processing of transmitting data read from the storage unit, and

the reader/writer determines that the data reading operation ends in failure if not receiving the read data from the IC tag.

15. The control method according to claim 13, wherein the data reading operation executed in the IC tag includes a processing of transmitting a detection result from the power supply voltage, and

if the power supply voltage is determined to be a predetermined value or lower based on the detection result from the IC tag, the reader/writer determines that the data reading operation ends in failure.

16. The control method according to claim 15, wherein the predetermined value is a voltage value at which the data reading operation can be executed in the IC tag.

17. The control method according to claim 14, wherein if the reader/writer determines that the data reading operation ends in failure, a distance between the reader/writer and the IC tag is changed, and the reader/writer sends a radio signal to the IC tag.