Hitachi, Ltd.

Ryo Nemoto

Kazuki Watanabe

Yoshiaki Yazawa

Hiroki Yamashita

Hiroshi Yoshigi

Keiichi Yamamoto

Yasushi Goto

Hisaaki Kanai

Fumio Yuuki

Tadashi Oonishi

In an RFID system including RFID tags each incorporating a sensor, accuracy of measurement by the sensor can be improved. For example, when measurements are performed several times by using RFID tags each incorporating a sensor unit, generation of a carrier directed from an RFID reader/writer to the RFID tags is stopped for a predetermined period every time when a measurement ends. By this means, the chip temperature of the RFID tag increased due to power consumption in each measurement can be reduced to, for example, ambient temperature every time when a measurement ends. Therefore, an error in measurement by the sensor unit can be reduced, thereby achieving accurate measurement.

RFID tag, RFID reader/writer, RFID system, and processing method of RFID system

A receiver circuit includes first and second constant current sources respectively connected to a pair of first and second receiving terminals to receive complementary current signals, a first NMOS transistor connected at a source thereof to the first receiving terminal and the first constant current source and connected at a drain thereof to a first power supply via a first output terminal and first load means, and a second NMOS transistor connected at a source thereof to the second receiving terminal and the second constant current source and connected at a drain thereof to the first power supply via a second output terminal and second load means.

Semiconductor device having transmitter/receiver circuit between circuit blocks

A level conversion circuit capable of realizing low-power/high-speed operation and suppression of variations in input/output characteristics due to variations in source voltage and temperature and device variation. The level conversion circuit comprises: a source follower circuit including a first transistor to input an AC signal of CML level thereto and a second transistor to input a control voltage thereto; and a control-voltage generating circuit to generate the control voltage to be inputted to the second transistor. The control-voltage generating circuit comprises: a replica source follower circuit which is a replica of the source follower circuit including a third transistor to input a central voltage of CML level thereto and a fourth transistor to input the control voltage thereto; and a comparator which controls the control voltage, thereby equalizing an output voltage of the replica source follower and a threshold voltage of a CMOS circuit.

Level conversion circuit

To augment the temperature dependence of the voltage used to detect temperature in a semiconductor integrated circuit device having a temperature detection function, the operating power supply voltage of the semiconductor integrated circuit device needed to be enhanced. It becomes possible for such a semiconductor integrated circuit device to generate a voltage of great temperature dependence, even under a low operating power supply voltage, by including: a temperature-to-current converter which outputs a first electric current proportional to temperature; a current generator which outputs a second electric current having extremely small temperature dependence; a current subtracter which outputs a third electric current proportional to a differential current obtained by subtracting the second electric current from the first electric current; and a current-to-voltage converter which converts the third electric current into a voltage.

Semiconductor integrated circuit device and a contactless electronic device

A measuring system enabled to simultaneously start measurement by a plurality of transponders by communication between a reader/writer and a plurality of transponders each with a built-in sensor is to be provided. In addition to an identifier SID intrinsic to a sensor and a chip identifier TID intrinsic to a transponder chip, a unique identifier UID combining the sensor SID and the chip TID is provided in each transponder. A reader/writer, in designating a transponder and transmitting a measurement command to it, invalidates the chip TID out of the UID of each transponder, validates only information regarding a sensor function, and transmits measurement commands including action commands unique to each type of sensor.

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Kokubunji, Japan

Ryo Nemoto