Renesas Technology Corp.

Renesas Electronics Corporation

Hitachi, Ltd.

Ttp Com Limited

Tipcom Limited

Kazuhisa Okada

Kazuhiko Hikasa

Patrick Wurm

Hiroaki Matsui

Ryoji Furuya

Satoru Yamamoto

Ryoichi Takano

David Freeborough

Kenji Toyota

The present invention provides a semiconductor integrated circuit for communication (RF IC) realizing high yield without deteriorating a carrier leak characteristic even when a modulation circuit is formed by using cheep parts with large variations. In a semiconductor integrated circuit (RF IC) including: an input circuit constructed by a differential amplifier circuit and a level shifter, which is provided on the ante stage of a mixer of a differential circuit called a Gilbert Cell; and a modulation circuit that performs modulation by adding an I/Q signal and a carrier wave signal, a calibration circuit for canceling a DC offset in an output of the input circuit is provided.

Semiconductor integrated circuit for communication

A polar loop based radio telecommunication apparatus which has a phase control loop for controlling the phase of a carrier outputted from an oscillator for transmitter, and an amplitude control loop for controlling the amplitude of a transmission output signal outputted from a power amplifier circuit, wherein precharge means is provided on a forward path from a current source, through the power amplifier circuit, to a detection circuit, forming the amplitude control loop, for rapidly increasing a control voltage for the power amplifier circuit to a power threshold upon starting transmission.

Apparatus for radio telecommunication system and method of building up output power

When a transmitting oscillator is built in a communication semiconductor integrated circuit device like a high-frequency IC constituting a wireless communication system, the system prevents degradation of the accuracy of control on the output power of a power amplifier due to noise jumped from an output pin of the transmitting oscillator to an input pin for a detected signal (feedback signal) of an output level of the power amplifier. The transmitting oscillator is built in the high-frequency IC. The detected signal of the output level of the power amplifier, which is detected by a coupler, is attenuated to a level slightly higher than the level of noise jumped from the output pin of the transmitting oscillator to the input pin for a feedback signal of an amplitude control loop, which in turn is inputted to the feedback signal input pin of the high-frequency IC.

Wireless communication system and communication semiconductor integrated circuit device

A semiconductor integrated circuit with a PLL (Phase Locked Loop) built therein is used in a semiconductor integrated circuit for wireless communication. The PLL circuit generates an oscillation signal having a predetermined frequency, which is combined with a receive signal or a transmit signal for wireless communication. The PLL circuit includes a VCO capable of switching an oscillation frequency band, a variable divider, a loop filter and a phase comparator. An oscillation frequency of the VCO is controlled according to the difference in phase between a signal obtained by dividing the output of the VCO and a reference signal, and a discrimination circuit makes a decision as to a lead or delay of the phase of an output of the variable divider with respect to a reference signal having a predetermined frequency. An auto band selection circuit generates a signal for selecting a frequency band for the VCO.

Semiconductor integrated circuit for wireless communication

A mobile communication system has a mobile phone in which a voltage is set corresponding to the characteristic variation of a PA even when a PA having characteristic variation is used. The mobile phone employs a polar loop method, which comprises an antenna () for transmission and reception of signal waves; an antenna switch () for switching the transmission mode and the reception mode; a BBLSI () having a function to control the transmission and reception; an RFIC () having a function for modulating and demodulating the transmitted and received signals; and a PA () for amplifying up to the target output power by means of the amplitude modulation at the time of the transmission.

Growing community of inventors

Kiryu, Japan

Kazuhisa Okada