Hitachi, Ltd.

Hitachi Information Technology Co., Ltd.

Densei Lambda K.k.

Naoki Maru

Hideho Yamamura

Shigeo Oomae

Koji Nisisu

Kazunori Nakajima

Katsumi Ishikawa

Ayumu Hatanaka

Satoshi Muraoka

Masakazu Yamamoto

Kaoru Kato

Satoshi Tomioka

Akihiro Sakurai

Mamoru Ogihara

Motoharu Ueguri

Hiroshi Kamee

The dead time is secured stably in a semiconductor drive circuit for switching devices using a wide band gap semiconductor. The drain terminal of the switching device of an upper arm is connected to the positive terminal of a first power supply, the source terminal of the switching device of a lower arm is connected to the negative terminal of the first power supply, and the source terminal of the switching device of the upper arm is connected with the drain terminal of the switching device of the lower arm. A gate drive circuit provided for each switching device includes an FET circuit and a parallel circuit made of a parallel connection of a first resistor and a first capacitor and having a first terminal connected to the gate terminal of the switching device.

Semiconductor drive circuit and power conversion apparatus using same

This invention prevents a deterioration of efficiency of a power supply apparatus due to a semiconductor power supply voltage drop, prevents an increase in wasted power, and prevents erroneous operations due to feeder wire voltage drop. In the mounting structure of electronic circuits having a plurality of busbars as current paths on a printed circuit board, the plurality of busbars have almost parallel portions spaced a predetermined distance apart; a span of the parallel portions of the plurality of busbars is greater than the predetermined distance; and in the parallel portions of the plurality of busbars, the plurality of busbars are connected by a wiring pattern. In the switching power supply apparatus built on a printed circuit board, with its output voltage of less than 2 V and its output current of more than 100 A, a means is provided for making the power efficiency higher than 70%.

Electronic circuit structure, power supply apparatus, power supply system, and electronic apparatus

An over voltage detection circuit, which is used in a power source, a power supply system, and an electronic apparatus, includes two voltage comparison circuits. A first comparison circuit, provided for high-speed signal responses, includes voltage dividing resistors, a voltage comparator, and a reference voltage source, while a second comparison circuit, provided for low-speed signal responses, includes voltage dividing resistors, a capacitor, a voltage comparator, and a reference voltage source. The second comparison circuit, which has the capacitor, is for low-speed-signal responses and does not respond to high-speed input changes, that is, high-frequency components. The first comparison circuit, which has no capacitor, responds to any frequency components including high-speed signals and high frequency components. A high setting voltage is selected for the first comparison circuit, while a low setting voltage for the second comparison circuit.

Over voltage detection circuit, and power source circuit, power supply system and electronic apparatus using the over voltage detection circuit

In a redundant configuration with multiple power sources connected in parallel to enhance reliability, a power source in which an overvoltage failure occurred has been difficult to identify and unable to be deactivated, which has impeded the improvement of reliability. However, it has become possible to deactivate selectively only the power source in which an overvoltage failure has occurred, by providing a independency-discrimination circuit that identifies the occurrence of the overvoltage failure by use of the state of a parallel operation control circuit, and connecting the independency-discrimination circuit, an overvoltage detection circuit, and a connection circuit.

Overvoltage protection circuit, and power source, power supply system and electronic apparatus using the overvoltage protection circuit

In the current detection circuit that detects the output currents of a switching power supply circuit, an improved current detection circuit makes it possible to detect the output current directions of power supplies solves the malfunction of the power supplies vibrating or diverging during changes in load state and during parallel operation, and thus implements stable operation. The direction of an output current Ican be detected by using the current detection circuitthat has multiple switching elements Sto Seach operating synchronously with an inverter circuit.

Current detection circuit, and power supply apparatus, power supply system and electronic apparatus using the current detection circuit

The present invention relates generally to D.C. power supplies and more particularly to overvoltage protection in one or more D.C. power supply circuits, where a plurality of D.C. power supplies may be connected together to supply power to an electronic system. In one embodiment a D.C. power supply circuit is provided which, when used with the plurality of D.C. power supply circuits connected in parallel, is capable of stopping only the power supply circuit having run into an overvoltage state with minimal effect on the other D.C. power supply circuits. Thus power to the load is continued.

D.C. power supply circuit and electronic apparatus using such circuits

A parallel power system is provided which can flexibly change output currents and the number of channels in short time and at low cost. A back board of the parallel power system has connectors ECC and DCC for plug-in mounting power source circuits to and an electronic circuit . Terminals of the connectors DCC and EDC are connected by wiring lines HP. The power source circuits to constitute a first voltage channel by a power source line DH and a parallel operation control line PCH of the electronic circuit , whereas the power source circuits to constitute a second voltage channel by a power source line DH and a parallel operation control line PCH . When a specification of the electronic circuit is to be changed, only the power source lines DH and DH and parallel operation control lines PCH and PCH are changed without changing the back board and the like.

Parallel power system and an electronic apparatus using the power system

An electronic circuit device having a power wiring resonance inhibition function includes a plurality of electronic circuit elements, and a wiring board having the electronic circuit elements disposed thereon. The wiring board includes a plurality of planar power supply wires for supplying power to the electronic circuit elements. The planar power wires include a pair of planar power supply wires for supplying power to the electronic circuit elements at a predetermined voltage. The electronic circuit device also includes a plurality of damping elements disposed at a plurality of positions on the wiring board. The damping elements are connected between the pair of planar power supply wires at a plurality of positions on the pair of planar power supply wires. The damping elements reduce power supply system impedance and inhibit power wiring system resonance, thereby reducing supply voltage fluctuation caused by the power wiring system resonance and noise caused by the supply voltage fluctuation.

Growing community of inventors

Hadano, Japan

Naoki Maru