Renesas Technology Corp.

Hitachi Ulsi Systems Co., Ltd.

Toshiki Matsui

Satoshi Tanaka

Kazuo Watanabe

Norio Hayashi

Noriyoshi Hagino

Hirotaka Oosawa

Ikuya Oono

The invention provides a signal processing semiconductor integrated circuit of the direct conversion system, which includes a dummy amplifier having the same circuit configuration as a low noise amplifier being the first stage amplifier, in which the DC offset calibrations on the subsequent stage amplifiers are carried out during shifting into the reception mode in a state that the low noise amplifier is deactivated and the dummy amplifier is activated. Thereby, the invention achieves to suppress generation of the DC offsets resulting from the leakage noises of the local oscillator during shifting into the reception mode, and to enhance the reception sensitivity.

Signal processing semiconductor integrated circuit device and wireless communication system

Disclosed herein is a direct conversion type signal processing semiconductor integrated circuit device capable of suppressing a DC voltage variation in the output of a variable gain amplifier upon the transition to a reception mode, reproducing stable receiving characteristics and improving receiving sensitivity. In the signal processing semiconductor integrated circuit device, voltage reference circuits for generating reference voltages for controlling or restricting currents for current sources for supplying operating currents for amplifiers constituting a reception-system circuit are boosted upon the transition from an idle mode or the like to the reception mode to allow the currents to flow into the constant-current sources of the amplifiers after the stabilization of the generated reference voltages.

Growing community of inventors

Takasaki, Japan

Toshiki Matsui