Renesas Technology Corp.

Hitachi, Ltd.

Ttpcom Limited

Renesas Electronics Corporation

Ttp Com Limited

Other

Hitachi Ulsi Engineering Corp.

Hitachi Tohbu Semiconductor, Ltd.

Hitachi Microcomputer Eng. Ltd.

Tipcom Limited

Ttp Communications Limited

Masumi Kasahara

Satoshi Tanaka

Kazuo Watanabe

Hirotaka Oosawa

Robert Astle Henshaw

Kumiko Takikawa

Taizo Yamawaki

Toshiya Uozumi

Noriyuki Kurakami

Masao Hotta

Kouichi Yahagi

Toyohiko Hongo

Tatsuji Matsuura

Kazuyuki Hori

Yukinori Akamine

Yasuyuki Kimura

Manabu Kawabe

Jiro Shinbo

Hiroki Nakajima

Hideo Nakane

Koichi Yahagi

Hirotaka Osawa

Koichi A Ono

Masahiro Ito

Masaru Kokubo

Takaya Yamamoto

Osamu Takada

Keisuke Kimura

Kazuaki Hori

Toshinori Hirashima

Hiroaki Matsui

Eiki Imaizumi

Shizuo Kondo

Julian Hildersley

Setsuo Ogura

Ryuichi Ujiie

Yoshitaka Jingu

Hisashi Okazawa

Akira Takigawa

Mikio Haijima

Oshima Takashi

Yoshiki Akamatsu

Junya Kudo

A semiconductor integrated circuit device having A/D converters for converting, by means of digital correction processing, analog input signals into digital signals is reduced in area. The semiconductor integrated circuit device has a first A/D converter and a second A/D converter. In a first mode, a first test signal is inputted to both the first and second A/D converters, and a first correction coefficient for the first A/D converter and a second correction coefficient for the second A/D converter are calculated. In a second mode, the first A/D converter converts a first analog signal into a first digital signal by subjecting the first analog signal to a first digital correction processing and the second A/D converter converts a second analog signal into a second digital signal by subjecting the second analog signal to a second digital correction processing.

Semiconductor integrated circuit device

A transceiver suitable for larger scale of integration employs direct conversion reception for reducing the number of filters. Also, the number of VCOs is reduced by utilizing dividers to supply a receiver and a transmitter with locally oscillated signals at an RF band. Dividers each having a fixed division ratio are used for generating locally oscillated signals for the receiver, while a divider having a switchable division ratio are used for generating the locally oscillated signal for the transmitter. In addition, a variable gain amplifier for baseband signal is provided with a DC offset voltage detector and a DC offset canceling circuit for supporting high speed data communications to accomplish fast cancellation of a DC offset by eliminating intervention of a filter within a feedback loop for offset cancellation.

Mobile communication apparatus

The present invention provides a PLL circuit containing a loop gain circuit capable of suppressing loop gain variation. This PLL circuit includes a counter that is driven by a voltage controlled oscillator within the PLL circuit, an accumulator (ACL) that accumulates the output of the counter, and a comparison operation circuit block that compares the count value of the ACL and the design value pre-stored in a register, and the loop gain of the PLL circuit is detected taking advantage of the fact that the ACL count value is inversely proportional to the loop gain. Based on the detection result, the loop gain is calibrated by correcting the loop gain with a charge pump current, etc. This allows the PLL circuit to maintain stable loop characteristics that will not affect the characteristics variation of each element constituting the PLL.

Phase locked loop circuit

The A/D converter converting an analog input signal into a digital output signal is constructed with a band pass &#x394;&#x3a3; modulator. The band pass &#x394;&#x3a3; modulator includes: a resonator showing a band-pass characteristic at a predetermined frequency and an attenuation characteristic at another frequency; a quantizer; and a local D/A converter. A signal of difference between the analog input signal and a local analog signal of the local D/A converter is supplied to the resonator. The A/D converter further includes an adder for supplying the analog input signal to an input of the quantizer. In addition, signal transmission circuits for reducing the influence of spike noise of the quantizer on the input to the resonator are connected between an input of the adder and an input of resonator selectively. The A/D converter constructed with the band pass &#x394;&#x3a3; modulator is improved in S/N ratio.

Semiconductor integrated circuit

A transmitter that can reduce noise without using an SAW filter whose IC integration is hard, and copes with two modulation formats of constant envelope modulation and non-constant envelope modulation, and a downsized and low-cost wireless communication apparatus that uses the transmitter are provided. The transmitter includes a quadrature modulator that modulates an input signal by quadrature modulation, a first amplifier that amplifies a modulation signal outputted by the quadrature modulator, and a second amplifier that amplifies an output signal of the first amplifier. The first amplifier operates as a limiter when the modulation format is the constant envelope modulation, and performs linear operation when the modulation format is the non-constant envelope modulation.

Transmitter and wireless communication apparatus using same

In a communication semiconductor integrated circuit device, an oscillator of a PLL circuit can operate in a plurality of frequency bands. With a control voltage (Vc) of the oscillator fixed to a predetermined value (VDC), an oscillation frequency of the oscillator is measured for each band to be stored in a storage. When the PLL operates, a setting value to specify a band is compared with the measured frequency values stored in the storage. As a result of the comparison, a band to be actually used by the oscillator is determined.

Communication semiconductor integrated circuit device and a wireless communication system

A &#x3a3;&#x394; transmitter that permits setting of a loop filter LF, a charge pump current and other factors to the same conditions even if it is operated in a plurality of frequency bands, therefore allows the number of components to be reduced and at the same time enables the angle between the phases of local signals for reception use to be close to exactly 90&#xb0;, which is a feature ensuring robustness against inter-element variations and accordingly suitable for large scale integration, is to be provided. The oscillation frequency of a VCO is set to an even-number multiple of the transmit frequency, and generates transmit signals via a divider. A device that varies the gain according to the amplitude component of modulating signals is added to an amplifier whose input is signals from the VCO, and the transmission of modulating signals involving amplitude modulation, such as EDGE, is thereby made possible.

Sigma delta (&#x3a3;&#x394;) transmitter circuits and transceiver using the same

Into an internal circuit to operate in a high-frequency band, there is incorporated a protective circuit of a multistage connection which is constructed to include a plurality of diode-connected transistors having a low parasitic capacity and free from a malfunction even when an input signal higher than the power supply voltage is applied. Into an internal circuit to operate in a low-frequency band, there is incorporated a protective circuit which is constructed to include one diode-connected transistor. The protective circuits include two lines of protective circuit, in which the directions of electric currents are so reversed as to protect the internal circuits against positive/negative static electricities.

A communication semiconductor integrated circuit has an oscillator circuit forming part of a transmission PLL circuit fabricated on a single semiconductor chip together with an oscillator circuit forming part of a reception PLL circuit and an oscillator circuit for an intermediate frequency. The oscillator circuit forming part of the transmission PLL circuit is configured to be operable in a plurality of bands. A circuit for measuring the oscillating frequency of the oscillator circuit forming part of the transmission PLL circuit is also used for measuring the oscillating frequency of the oscillator circuit forming part of the reception PLL circuit or for measuring the oscillating frequency of the oscillator circuit for the intermediate frequency.

Communication semiconductor integrated circuit and radio communication system

An image input system includes a solid state image pickup device and a preprocessor for performing correlated double sampling amplification on an output of the image pickup device and outputting a video signal. The preprocessor has a correlated double sampling amplifier for outputting signal information corresponding to a difference voltage between the black level in a feedthrough period of the image pickup device and a signal level in a charge signal output period; and an offset cancelling circuit for cancelling an offset voltage corresponding to the difference voltage in a state where the image pickup device is optically interrupted to the input terminal of the correlated double sampling amplifier. The correlated double sampling amplifier cancels out the offset voltage and the offset cancelling voltage as signal components of polarities opposite to each other, so that circuits following the correlated double sampling amplifier are not influenced by the offset voltage.

Image input system

A semiconductor integrated circuit device for communication is provided with a PLL circuit or the like formed therein, the PLL circuit which is capable of realizing the compensation of fluctuation due to temperature change, the inhibition of increase in the chip area and the ensurement of the performance margin, and which controls a VCO having multiple oscillation frequency bands. In the case where automatic calibration is performed by switching a switch to a side of a DC voltage source in the PLL circuit using a VCO having multiple oscillation bands, a tuning voltage (Vtune) of an RFVCO is fixed to a voltage value of a DC voltage source. However, since a temperature characteristic of canceling a VCO oscillation frequency is given to the DC voltage source, it is possible to minimize the influence on the band selection when a calibration table comes to no optimum one.

PLL circuit having a multi-band oscillator and compensating oscillation frequency

Growing community of inventors

Takasaki, Japan

Masumi Kasahara