Hitachi, Ltd.

Other

Hitachi Haramachi Semi-conductor, Ltd.

Koichi Suda

Katsumi Ishikawa

Masataka Sasaki

Hideki Miyazaki

Ryuichi Saito

Katsuaki Takahashi

Shoichi Ozeki

Tsunehiro Endo

Katsunori Suzuki

Yuhachi Takakura

Kouzou Watanabe

Keiichi Morita

Masayuki Wada

Hitoshi Matsuzaki

Tomoyuki Utsumi

Kunihiro Matsukuma

Yasuhiro Kida

A drive circuit that controls a switching device ON/OFF and a soft cutoff command circuit that gradually decreases the gate terminal voltage of the switching device when short circuit of the switching device is detected. Additionally, an ON-pulse retention command circuit retains the output of the drive circuit ON when the gate terminal voltage is judged to have exceeded a specified value by a gate voltage judgment comparator that detects the gate terminal voltage of the switching device.

Drive circuit for switching device

A level shifting circuit, satisfying a requirement of a high tolerated dV/dt level, and a highly reliable inverter circuit, wherein a set pulse signal and a reset pulse signal, both of which are level-shifted to a potential side taking as reference a reference potential of a gate control terminal of a switching terminal, are obtained differentially and integrated, and, in case these pulse signals equal or exceed stipulated integrated values, are transmitted as regular control signals controlling the on/off state.

Driving circuit for switching elements

A collector voltage of a power management semiconductor device is detected by a first comparator, and when the detected collector voltage exceeds a first reference voltage, the first comparator outputs a first detection signal. Furthermore, a gate voltage of the power management semiconductor device is detected by a second comparator, and when the detected gate voltage exceeds a second reference voltage, the second comparator outputs a second detection signal. The second reference voltage is a minimum gate voltage for feeding a rated power to the power management semiconductor device or over, and less than a line power voltage of a drive circuit of the power management semiconductor device. When both the first detection signal and second detection signal are being outputted, the gate voltage is reduced by a gate voltage reduction means so as to protect the power management semiconductor device from overcurrent and overvoltage.

Protection circuit for power management semiconductor devices and power converter having the protection circuit

To provide a highly reliable inverter apparatus which discriminates long-cycle noise generated by the isolated signal transmission element from short-cycle dv/dt noise and induction noise. A low pass filter, band pass filter, and a switching means are provided between the input section of the gate drive circuit of the voltage-drive type power semiconductor switching element and the isolated signal transmission means that transmits the output of the control circuit; and an abnormal signal discriminating circuit is also provided which turns on and off the switching means according to the output of the band pass filter thereby eliminating long-cycle noise derived from the isolated signal transmission element, short-cycle dv/dt noise, and induction noise; and also outputs alarm signals.

Inverter apparatus

A drive circuitthat controls a switching deviceON/OFF and a soft cutoff command circuit that gradually decreases the gate terminal voltage of the switching devicewhen short circuit of the switching deviceis detected. Additionally, an ON-pulse retention command circuitretains the output of the drive circuitON when the gate terminal voltage is judged to have exceeded a specified value by a gate voltage judgment comparatorthat detects the gate terminal voltage of the switching device

An insulated gate transistor comprising a first semiconductor region, a second semiconductor region includes plural portions, a third semiconductor region, a fourth semiconductor region, a first insulation layer, control electrodes, a first main electrode, and a second main electrode, wherein a metallic wiring layer is provided on the first main surface plane via an insulating layer, plural regions insulated from the first main electrode are provided through said first main electrode, and the metallic wiring layer is connected electrically to the control electrode through the insulating layer via the region insulated from the main electrode.

Insulated gate bipolar transistor decreasing the gate resistance

An inverter apparatus includes a flip-flop circuit and a voltage clamp circuit disposed in the upper arm, and set and reset signal generators each having a series connection of two switching devices. By using an input signal and using an output signal of the flip-flop circuit, the above described two switching devices are activated in a complementary manner. Owing to this configuration, no current flows except a minute time for supplying a trigger signal to the flip-flop circuit, resulting in low current consumption. If the output logic of the flip-flop circuit has been inverted by noise, two switching devices are simultaneously in the on-state and a re-trigger current is let flow to restore the above described output logic to the normal state, resulting in the complementary state again. As a result, signal transmission between the upper and lower arms is performed at higher speed and with a lower loss. In addition, the inverter apparatus is protected from false operation due to noise.

Level shift circuit and inverter apparatus using the same

A switching circuit providing detection circuit for detecting a current which flows through a main P-channel MOSFET detection of a floating voltage dependent upon a power supply potential, a reference-voltage generating circuit for generating a reference voltage which is a floating voltage dependent upon the power supply potential and has a constant value independently of variations in power supply potential, a comparator circuit operated on a supply voltage which is a floating voltage dependent upon the power supply potential, for comparing a detected voltage from the detection circuit with the reference voltage from the reference-voltage generating means, to convert the detected voltage into a logic voltage signal (i.e., a bi-level voltage signal and a conversion circuit for converting the logic voltage outputted by the comparator circuit into a voltage measured from a ground potential.

High-side switch with overcurrent protecting circuit

In a method of manufacturing a solar cell including a p-n junction formed in a semiconductor substrate, impurity ions are implanted through a mask in the form of an oxide film covering a light receiving surface of the semiconductor substrate except an electrode forming part, thereby forming a p-n junction which is deep in an area beneath the electrode forming part but shallow in the remaining area. Formation of the shallow p-n junction improves the spectral sensitivity in a short wavelength range. Further, utilization of the oxide film as a passivation film can prevent shortening of the life time of minority carriers in the substrate due to heat treatment, thereby retarding the electron-hole recombination rate at the light receiving surface of the substrate.

Growing community of inventors

Mito, Japan

Koichi Suda