Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Noritz Corporation

Akira Ohta

Akira Inoue

Norio Higashisaka

Tetsuya Heima

Kazutomi Mori

Shintaro Shinjo

Noriharu Suematsu

Seiki Gotou

Seiki Goto

Hiroaki Seki

Masaaki Shimada

Koji Yamanaka

Masatoshi Nakayama

Kazunori Takahashi

Teruyuki Shimura

Kazuhiro Ueda

Kazuhiro Iyomasa

Eigo Kuwata

Masaharu Hattori

Shohei Imai

Hiroaki Maehara

Yoshihisa Kitano

Yoshifumi Atobe

Tomoki Kishimoto

Hiroomi Ueda

Daisuke Konishi

Haruki Inoue

Yoshitaka Kimura

Ryo Ikeda

Yasuhide Ikeuchi

Tomoya Nakano

Shingo Matsuda

A solenoid valve driving apparatus includes switching means for ON/OFF-controlling application of a direct current voltage to a solenoid of a solenoid valve, and signal outputting means. A first period and a consecutive second period are set as a valve opening operation period of the solenoid valve. When the signal outputting means outputs the PWM signal to the switching means, a duty ratio of the output signal is set to be higher in the second period than in the first period so that a power supplied to the solenoid is larger in the second period than in the first period. As a result, a valve opening operation is performed in the solenoid valve reliably, and loud noise generation during the valve opening operation is suppressed.

Driving method for solenoid valve, solenoid valve driving apparatus, and combustion apparatus including same

A multi-finger transistor includes a circuit suppressing a variation in voltage current distribution. The circuit connects gate fingers () to each other, or source fingers () to each other in a region which is located outside an active region () and on a side where a drain pad () is disposed. The multi-finger transistor is configured to be linearly symmetric with respect to a direction of propagation of a signal from a gate pad () at the position of the gate pad ().

Multi-finger transistor and semiconductor device

Provided is a high frequency amplifier including two amplifying elements of different element sizes connected in parallel and switching the amplifying elements in accordance with a level of output power. In particular, the high frequency amplifier includes an output matching circuit for matching to characteristic impedance (50 ohms) both when the output power is high and low, and increasing impedance when the turned-off amplifying element is viewed from a connection node on an output side of the two amplifying elements. Consequently, characteristics such as high output power and high efficiency can be achieved and it is possible to prevent an amplified high frequency signal from passing around to a matching circuit on a turned-off amplifying element side.

High frequency amplifier

A high-power amplifier changes matching conditions of an output matching circuitconnected between a final stage amplifying elementand an output terminalin response to the output power of the amplifying element. Thus, the efficiency at low output power can be greatly improved without reducing the efficiency at the maximum output. Besides, since it is not necessary to load a DC-DC converter, an increase in size or cost can be prevented.

High-power amplifier

A high frequency power amplifier includes: a multi-finger transistor including transistor cells electrically connected in parallel; an input side matching circuit connected to gate electrodes of the transistor cells; and resonant circuits, each resonant circuit being connected between a gate electrode of a respective one of the transistor cells and the input side matching circuit. The resonant circuits resonate at a second harmonic of the operational frequency of the transistor or at a frequency within a predetermined range centered at the second harmonic and act as a short circuit or exhibit low impedance as seen from the gate electrode.

High frequency power amplifier

A high frequency amplifier includes a constant voltage driven amplifierusing as its amplifying element a bipolar transistorwith its base biased by a constant voltage, and a constant current driven amplifierusing as its amplifying element a bipolar transistorwith its base biased by a constant current. The idle current of the constant current driven amplifieris set at a low value. In accordance with the idle current, the idle current of the constant voltage driven amplifieris adjusted, and the two amplifiers are combined in parallel.

High-frequency amplifier

A semiconductor chip for amplification is connected between input-side and output-side matching circuits, and each of matching circuits includes balanced circuits which receive signals different in phase by 180 degrees, divided from an input signal. The balanced circuits are connected at a virtual grounding point, which is used as a grounding point sensitive to RF characteristics in an IPD. Thus, a semiconductor device can be free from influence of variations of grounding wires and can be reduced in size, weight, and cost.

Semiconductor device having balanced circuit for use in high frequency band

A second strip conductor is located, in a lamination direction of a multilayer substrate, at a is different position from that of a first strip conductor. A first grounding conductor and a second grounding conductor are disposed sequentially in the lamination direction of the multilayer substrate and sandwich the first strip conductor and the second strip conductor. The first grounding conductor includes a first grounding conductor portion for a wiring prohibited area in which no wiring may be placed, and a second grounding conductor portion for an area other than the wiring prohibited area. The second grounding conductor portion is positioned, in the lamination direction of the multilayer substrate, at a location is different from that of the first grounding conductor portion.

High-frequency power amplifier

A high-frequency amplifier in a power amplifier module includes, on a substrate on which the amplifier is formed, first- and second-stage amplifiers for receiving and amplifying an input signal, a harmonic processing circuit for matching of harmonics included in an output signal from the second-stage amplifier, and a low-pass filter receiving an output from the harmonic processing circuit to selectively pass a signal to be supplied to a non-reciprocal circuit element using a predetermined frequency as a cutoff frequency.

High-frequency amplifier and radio transmission device with circuit scale and current consumption reduced to achieve high efficiency

A low impedance high efficiency amplifier is connected to a low impedance isolator. The low impedance high efficiency amplifier includes a plurality of amplifiers and an output matching circuit having a harmonic processing circuit arranged between a fundamental wave regulator circuit/a final stage amplifier and the low impedance isolator.

High efficiency amplifier with amplifier element, radio transmission device therewith and measuring device therefor

A resonance circuit of a transmission line and a capacitor is connected to the base circuit of a transistor. The transmission line is shorter than one-quarter wavelength to make the resonant frequency of the resonant circuit higher than the frequency of a second harmonic. As a result, the angle of the reflection coefficient of the second harmonic when an input matching circuit side is viewed from the input terminal of the transistor ranges from 170&deg; to 270&deg; on a polar chart, and phase difference between the fundamental wave of the base current and the second harmonic decreases.

A high frequency power amplifier that can improve efficiency of an operation of a transistor without limiting any input-side higher harmonic load of an impedance matching circuit to a short-circuit load, and can increase reflection of higher harmonics. By adjusting line lengths and line widths of signal lines, a 2nd harmonic can be adjusted to be an open load (a reflected phase angle of &Ggr;in: 0-90&deg;, the quantity of reflection: 0.6-1.0), and a 3rd harmonic is adjusted to be a short-circuit load (the reflected phase angle of &Ggr;in: 110-270&deg;, the quantity of reflection: 0.6-1.0). With this input-side higher harmonic load of the impedance matching circuit, efficiency of transistor operation can be improved. By disposing a higher harmonic processing circuit closer to a transistor, a high frequency power amplifier with a shortened line length between the higher harmonic processing circuit and the transistor, and increased quantity of reflection of higher harmonics is produced.

A radio-frequency composite element includes an element substrate carrying a high-efficiency amplifier, a transmission line, and an isolator. The amplifier is a semiconductor element mounted on a multilayer substrate and enveloped by a cover. The transmission line furnished on the element substrate connecting an output terminal of the high-efficiency amplifier with an input terminal of the isolator, so that the components make up an integral composite element.

Radio-frequency composite element

A high frequency power amplifier with reduced power loss and improved power amplification efficiency has an output matching circuit providing an open circuit to a second harmonic and a short circuit to a third harmonic of a high frequency signal. This is accomplished by, for example, adjusting lengths of a drain bias line and a plurality of signal lines so that the phase of S parameter S11 (input reflection coefficient) to the second harmonic is from &minus;80&deg; to 140&deg;, and the phase of S parameter S11 to the third harmonic is from 160&deg; to 220&deg;. The line length of each line in an input matching circuit is also adjusted so that the phase of S parameter S22 (output reflection coefficient) at the fundamental frequency is between &plus;5&deg; to &minus;75&deg;.

A variable delay circuit that delays an input signal for a desired time and outputs the delayed signal includes N (N is an integer of 2 or more) load transistors and N control transistors for controlling the load transistors respectively connected in pairs in series to form N load transistor pairs. The load transistor pairs are connected in parallel to form a load transistor group. A switching transistor that is turned on or off according to an input signal input to a gate, and the load transistor group are connected in series between first and second power supplies. The input signal is delayed according to control signals that are respectively input to the control transistors, and a delayed signal is output from a connection node of the load transistor group and the switching transistor. Since no selector is required, a delay circuit operation due to differences in delay times between paths in a selector is avoided, thereby obtaining a variable delay circuit having minute resolution and a good yield.

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Tokyo, Japan

Akira Ohta