Renesas Electronics Corporation

Ntt Docomo, Inc.

Norihisa Yamamoto

Shin Morita

Tomohiro Akiyama

Kunio Yoshikawa

Kumiko Yamaguchi

Tetsuhiro Tanno

Tetsuhiro Sasagawa

Kazuaki Gemma

Sumi Kawabata

Satoshi Akita

The present invention provides a noncontact interface technique capable of performing communication operation without stopping an internal operation even when a clock signal cannot be extracted from a carrier wave. In a semiconductor device that receives a modulated carrier wave from an antenna, generates an internal clock signal on the basis of a clock signal extracted from the received carrier wave, and performs operation synchronously with the internal clock signal, a PLL circuit that receives the extracted clock signal and generates the internal clock signal is provided with a voltage control oscillation function. In the case where the clock signal extracted from the carrier wave is discretely interrupted, the function makes the internal clock signal maintained at a frequency immediately before the interruption. With the configuration, even when the clock signal extracted from the carrier wave is interrupted, internal data processes such as decoding and bus interfacing can be continued.

Semiconductor device, portable communication terminal, IC card, and microcomputer

A portable terminal supplies power to a chip card therein with host power off. A power controller supplies power from a battery to a host, the chip card, and a CLF; a first switch opens/closes a power supply channel to the chip card, branching from a power supply channel from the power controller to the host; a second switch opens/closes a power supply channel to the chip card, branching from a power supply channel from the power controller to the CLF; a switch controller opens the first switch and closes the second switch if the CLF detects a contactless RF signal, if the host is off or if the portable terminal is in a low battery mode, and if the contactless RF signal conforms to the communication method of the chip card, and the switch controller closes the first switch and opens the second switch if the host is on.

Portable terminal, recording medium

The detector is reduced in DC power consumption when an input signal is at a low amplitude level. The detector includes first and second input terminals, first and second transistors, and a load element. The first and second input terminals are supplied with complementary input signals reverse to each other in phase. The first input terminal is connected to the first input electrode of the first transistor and the second input electrode of the second transistor. The second input terminal is connected to the second input electrode of the first transistor and the first input electrode of the second transistor. The load element is connected between output electrodes of the transistors and an operating voltage point. A detection voltage resulting from full-wave rectification arises from a circuit node. In the condition where a signal input to the input terminals is at a low amplitude level, the transistors are both in OFF state. Thus, DC power consumption is reduced.

Detector, RF circuit with detector, and mobile device with RF circuit

Growing community of inventors

Tokyo, Japan

Norihisa Yamamoto