Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Joji Hayashi

Katsumasa Hijikata

Takashi Nakamura

Hiroshi Kimura

Takashi Morie

Hiroshi Shimomura

Takehiro Hirai

Akinori Matsumoto

Hirokuni Fujiyama

Hiroya Ueno

Ryangsu Kim

In a high-frequency amplifier for amplifying transmission and reception signals, an integrated circuit area is reduced to reduce production costs. A high-frequency amplifier () includes a reception signal amplifying part (), a transmission signal amplifying part (), and a spiral inductor (). An output of the reception signal amplifying part () is connected with an output of the transmission signal amplifying part () to be an output terminal OUT of the high-frequency amplifier (). The single spiral inductor () is connected to the output terminal OUT. This spiral inductor () is used as a load common to the reception signal amplifying part () and the transmission signal amplifying part (). Thereby, the area of the integrated circuit is reduced, and the production cost is reduced.

High-frequency amplifier, and transmission/reception system

In a broadband low-noise amplifier circuit to be used in a multichannel reception system, a capacitance of a variable capacitor () is controlled by a resonance frequency control circuit () so that a resonance frequency of a load unit () comprising the variable capacitor () and an inductor () matches a desired RF signal frequency. Therefore, high gain and broadband can be realized at the same time without increasing power consumption, and consequently, a reception system having reduced power consumption and high sensitivity for all channels can be realized.

Low-noise amplifier circuit and receiving system

A variable gain amplification circuit comprises a signal generator that has an output terminal and is able to vary an output amplitude; a variable capacitor connected between the output terminal and an AC grounded terminal; and a control circuit for controlling the output amplitude of the signal generator, and a capacitance of the variable capacitor. Therefore, unnecessary signals can be attenuated even when the gain is low, and degradation in distortion characteristics in the latter block can be suppressed.

Variable gain amplification circuit

A mixer circuit of a receiving system, requiring low noise characteristics at lower frequency, includes a bypass current source () which is connected in parallel with an LO transistor () between an IF output terminal () and a drain terminal of an RF transistor (), and a bypass current source () which is connected in parallel with an LO transistor () between an IF output terminal () and the drain terminal of the RF transistor (), thereby decreasing a current flowing through the LO transistors () without decreasing a bias current flowing through the RF transistor (). Accordingly, it is possible to suppress flicker noises occurring from the LO transistors () without lowering the gain of the mixer, thereby realizing a mixer circuit with excellent low frequency noise characteristics, which can improve the NF characteristics at lower frequency.

Mixer circuit

A pseudo-image signal producing section produces a pseudo-image signal imitating an actual image signal. An amplitude detection section detects the amplitude of the pseudo-image signal having passed through a complex filter circuit. A filter control section controls an element value control section in the complex filter circuit so as to decrease the detected amplitude. The element value control section performs an element value adjustment so that absolute element values of a pair of elements corresponding to each other in two filter circuits in the complex filter circuit increase/decrease in opposite directions.

Complex filter circuit and receiver circuit

A contactless IC card includes a reference voltage circuit, a judging circuit for monitoring a reference voltage that is outputted from the reference voltage circuit, and a power supply stabilization, unit. The judging circuit judges whether the reference voltage is equal to or higher than a predetermined voltage. When the reference voltage does not reach the predetermined voltage, the power supply stabilization unit supplies energy to the power supply to suppress a steep increase in the power supply voltage, thereby stabilizing the power supply in the contactless IC card and suppressing deterioration of the signal quality.

Contactless IC card

A power supply circuit of the present invention includes: a current detection circuit connected between a first power supply voltage section for applying a first power supply voltage to a first electronic circuit and a second power supply voltage section for applying a second power supply voltage to a second electronic circuit, the current detection circuit having a monitor terminal for monitoring a current flowing from the first power supply voltage section to the second power supply voltage section; and a current compensation circuit connected to the first power supply voltage section and the monitor terminal, the current compensation circuit controlling a compensation current flowing from the first power supply voltage section to a ground based on the monitored current to compensate for current fluctuations caused by load fluctuations of the second electronic circuit.

Power supply circuit and RF transponder IC

The present invention has an objective of providing a semiconductor amplifier circuit having a cascode amplifier in which a negative characteristic of an output conductance is improved at least in a particular frequency band. A semiconductor amplifier includes a cascode amplifier having a transistor and a transistor which are cascaded, and improvement means for improving the negative characteristic of the output conductance G of the cascode amplifier at least in a particular frequency band.

Semiconductor amplifier circuit and system

In an active area surrounded with an isolation formed on a silicon substrate, a large number of unit cells are disposed in a matrix, and the unit cell together form one MOSFET. Each of the unit includes a ring gate electrode in the shape of a regular octagon, a drain region and a source region formed at the inside and outside of the gate electrode, respectively, two gate withdrawn wires extending from the gate electrode to area above the isolation, a substrate contact portion in which the surface of the substrate is exposed, and contacts for electrically connecting these elements with wires. These elements such as the ring gate electrode and the gate withdrawn wires are formed so as to attain a high frequency characteristic as good as possible. Thus a MOSFET for use in a high frequency signal device, the high frequency characteristic such as the minimum noise figure and the maximum oscillation frequency in particular can be totally improved.

Growing community of inventors

Osaka, Japan

Joji Hayashi