Sumitomo Electric Industries, Limited

Toyohashi University of Technology

National University Corporation Toyohashi of Technology

National University Corporation Toyohashi University of Technology

Nobuo Shiga

Takashi Ohira

Takeshi Sekiguchi

Kazuhiro Fujikawa

Kazuyuki Wada

Sosaku Sawada

Satoshi Hatsukawa

Hideaki Nakahata

Kenichi Hirotsu

Kenji Otobe

Kyohei Yamada

Kazuya Ishioka

Tuya Wuren

Hiromi Kurashima

Daisuke Takagi

Keigo Aga

Ryoji Sakamoto

Kazushi Sawada

Takashi Tsuno

Ichiro Tonai

Shigeru Nakajima

Nobuhiro Kuwata

Ken-ichiro Matsuzaki

Daiya Egashira

Ken-ichi Yoshida

Ken-ichi Kitayama

Hisato Takahashi

Kotaro Tanimura

Satoshi Ohe

Mitsutoshi Nakata

A transformer is provided between a power supply and a load, and includes a front stage circuit and a rear stage circuit each having a function of performing switching so as to alternately invert a polarity of output relative to input. The transformer further includes: a series unit provided in at least one of both circuits and composed of a pair of reactance elements connected in series to each other via a connection point; and a switch device which, with both ends of the series unit serving as a first port, causes a part between one end of the series unit and the connection point, and a part between the other end of the series unit and the connection point, to serve as a second port alternately through switching while inverting a polarity, and executes power transmission from the first port to the second port or vice versa.

Transformer

A transformer is provided between a power supply, and a load with a resistance value R, and includes a two-terminal pair circuit composed of n-number of reactance elements that are mutually connected, where n is a natural number equal to or greater than 4. With respect to any value of the resistance value R of the load, an input impedance Zof the two-terminal pair circuit has a real number component of k&#xb7;R, where k is a constant, and an imaginary number component of 0. Such a transformer has a small size and a light weight, and does not need a coil, an iron core, and the like as used in a conventional transformer.

A transformer of distributed-constant type is provided between an AC power supply with a frequency f and a load with a resistance value R, and includes: a first converter connected to the AC power supply and having a length of &#x3bb;/4; and a second converter provided between an end of the first converter and the load, and having a length of &#x3bb;/4, where a wavelength at the frequency f is &#x3bb;. Such a transformer has a small size and a light weight, and does not need a coil, an iron core, and the like as used in a conventional transformer.

Distributed-constant type transformer for voltage conversion

A power inverter circuitis a bridge power inverter circuit comprising first and second switching elementssequentially connected in series between input terminals on higher and lower voltage sides and third and fourth switching elementssequentially connected in series between the input terminals on the higher and lower voltage sides and alternately turning on a set of the first and fourth switching elementsand a set of the second and third switching elementsso as to convert a DC power fed between the input terminals on the higher and lower voltage sides into an AC power. One of the sets of the first and third switching elementsand the second and fourth switching elementsis subjected to switching control at a frequency higher than that of the other.

Power inverter circuit having switching elements

Provided is a transistor protection circuit capable of appropriately protecting a transistor even when a switching frequency is high. A transistor protection circuit according to an embodiment of the present invention is a transistor protection circuit for protecting a voltage-driven transistor that is switch-controlled by the application of a high-potential-side voltage or low-potential-side voltage of a power supply to a gate terminal of the transistor by a drive circuit. The transistor protection circuit has a power supply controller that gradually lowers the high-potential-side voltage of the power supply upon receiving a protection command for executing protection of the transistor.

Transistor protection circuit

A switching circuitcomprises a connection circuit cascade-connecting control terminals for controlling switching of n number of transistors M-Mn via n&#x2212;1 number of coils Lrespectively (n is an integer equal to or more than 2; and coils Lrespectively connected between one end of each of the transistors M-Mn and other end of a coil L, one end of the coil Lbeing electrically connected to a DC power source. The transistors M-Mn is sequentially switched with PWM signals inputted to an input terminal of the connection circuit. The switching circuitfurther comprises a transistor Minserted at the one end or the other end of the coil Lin cascade-connection.

Switching circuit and envelope signal amplifier

A switching circuit according to one embodiment has: N switching elements; a connection circuit including N&#x2212;1 first inductance elements that are connected in series; a second inductance element; and N third inductance elements. Control terminals of the N switching elements are connected to ends of the connection circuit and connection contacts, respectively. One end of the second inductance element is connected to a power supply. The N third inductance elements electrically connects one ends of the N switching elements and the other end of the second inductance element with each other, respectively.

A switching circuit according to one embodiment includes first to fourth semiconductor switch elements. A pulse-like signal is applied to each input terminal of the switch elements such that when the first and fourth switch elements are in an ON (OFF) state, the remaining switch elements are in an OFF (ON) state. The switching circuit includes first and second capacitance elements. The first capacitance elements connected between an output terminal of the second semiconductor switch element and the second capacitance elements connected between an input terminal of the second semiconductor switch element and an output terminal of the fourth semiconductor switch element has a capacitance to reduce a parasitic capacitance between the input and output terminals of each of the fourth and second switch elements at a frequency N times (N is an integer of 1 or more) as high as a clock frequency of the pulse-like signal.

Switching circuit

A switching circuit according to one embodiment is a switching circuit including at least one semiconductor switch element having an input, output, and a common terminals, a pulse-like signal being applied between the input and common terminals to switch a current between the output and common terminals. The switching circuit further includes a capacitance suppression element section connected at least one of between the input and output terminals, between the input terminal common terminals, and between the output and common terminals. The capacitance suppression element section reduces a parasitic capacitance between the terminals of the semiconductor switch element where the capacitance suppression element section is connected to less than that obtained when the capacitance suppression element section is not connected at a frequency N times (N is an integer of 1 or more) as high as a clock frequency of the pulse-like signal.

A switching circuit according to one embodiment includes: a switching element that has a first terminal and a second terminal, and is driven by a pulse signal to switch a conduction state between the first and second terminals; a power source section that supplies a voltage to the first terminal; a load circuit that is connected in parallel with the power source section; a passive circuit section that is connected between a connection point between the power source section and the load circuit, and the first terminal, and suppresses a current flowing from the connection point to the switching element at a frequency N times (N is an integer of 1 or more) as high as a clock frequency of the pulse signal; and a resonant circuit section that is connected between the passive circuit section and the connection point, and resonates at the frequency of N times.

Optical receiver/transmitter module

It is an object of the present invention to provide a highly reliable optical module circuit board having a sufficient mechanical strength with respect to an external stress. An optical module circuit board according to the present invention includes a flexible printed circuit having at least a multilayered structure in which a layer containing a conductive metal interconnection is sandwiched between insulating layers, wherein the flexible printed circuit includes a main body portion having the multilayered structure, a first surface mounted with an electronic component, and a second surface opposite to the first surface, a neck portion having the multilayered structure and extending from one end of the main body portion, and a head portion positioned at a distal end of the neck portion extending from the one end of the main body portion, having the multilayered structure, and mounted with an optical operation element and a bypass capacitor, Particularly, the neck portion defines the positional relationship between the main body portion and the head portion so as to give the circuit board a sufficient mechanical strength.

Optical module circuit board having flexible structure

A package semiconductor device comprises an insulating substrate having an upper surface formed with a plurality of connection pads and an under surface formed with a plurality of external connection members each of which is electrically connected to a corresponding one of the connection pads through a via hole formed through the insulating substrate. An integrated circuit chip is bonded facedown on the upper surface of the insulating substrate so that the integrated circuit chip is electrically connected to the connection pads through solder bumps. An electrically conductive cap is covered on the first surface of the insulating substrate so that the integrated circuit chip is encapsulated in a space defined by the insulating substrate and the conductive cap. A back electrode of the integrated circuit chip is electrically connected to the conductive cap through an electrically conducting element.

Packaged semiconductor device suitable to be mounted and connected to

It is an object of present invention to provide a low-cost photoelectric conversion module in which a signal for compensating noise caused by changes in temperature and variations in power supply is obtained. In the photoelectric conversion module according to the present invention, a first amplifier having an input terminal connected to the anode of a light-receiving element for converting an optical signal into an electrical signal amplifies the electrical signal to obtain an amplified signal. A second amplifier having an input terminal connected to one electrode of a capacitor outputs an amplified signal for compensating noise of the electrical signal amplified by the first amplifier. The other electrode of the capacitor is connected to the cathode of the light-receiving element. The capacitor has a capacitance value equal to the capacitance of the light-receiving element.

Photoelectric conversion module with noise compensation

In a mixer circuit, a first gate electrode of a dual gate MESFET having a pulse doped structure is connected through a filter to an LO signal input terminal, and a second gate electrode of the dual gate FET is connected through a matching circuit to an RF signal input terminal. The drain electrode of the dual gate FET is connected through a low-pass filter to an output terminal. The gate bias point of the first gate electrode 25a of the dual gate FET is set in the vicinity of the pinch-off point of the mutual conductance, and the gate bias point of the second gate electrode 25b of the dual gate FET is set in the area where the mutual conductance is unvaried with increase of the gate voltage. With this arrangement, the mixer circuit is so designed that the isolation characteristic of the RF signal and the LO signal is excellent, and a stable operational characteristic is obtained.

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Yokohama, Japan

Nobuo Shiga