Tdk Corporation

Oki Electric Industry Co., Ltd.

Yoshihisa Okita

Katsuaki Tanaka

Kazuyuki Itoh

Katsumi Yabusaki

Shiro Nakagawa

Yoshinobu Takayanagi

Kazuyuki Ito

A power conversion apparatus capable of reducing the conduction loss to achieve high efficiency yielding a downsized and weight-reduced apparatus and a method for driving such a power conversion apparatus is disclosed. A power conversion apparatus comprising a switching-element driving circuit which includes a current transformer having a primary coil connected to an current control type switching element, and a driving-current generating circuit formed of a secondary coil of the current transformer and a rectifying circuit connected to the secondary coil, wherein an output current generated in the driving-current generating circuit is supplied to the switching element as a driving current of the switching element, and a method for driving the switching element of such a power conversion apparatus are disclosed. This method comprises the steps of detecting an output current of the switching element, and extracting a part of the output current of the driving-current generating circuit out of the switching-element driving circuit so as to variably controlling the driving current of the switching element in response to the output current of the switching element. Preferably, the output current of the driving-current generating circuit extracted out of the switching-element driving circuit is supplied to any other auxiliary power supply as a regenerative power.

Method and apparatus for driving switching element in power converter

Power conversion apparatus utilizing soft switching resonant snubber circuitry

In a power conversion apparatus using a semiconductor switching element, a collector-emitter voltage detecting device is provided to detect the collector-emitter voltage in the semiconductor switching element in the power conversion apparatus in order to comprehensively reduce switching loss and conduction loss arising in a switching element. A base current supplied to the switching element is controlled based on the detected collector-emitter voltage so as to control the collector-emitter voltage or control a regenerative power to be transmitted from a switching element driving power supply to an external auxiliary power supply or the like. This provides an optimum driving in consideration of factors including dispersion in a specific current amplification factor (hfe) of the switching element, variance in the hfe caused by temperature, and variance in the hfe to a current flowing through the switching element, for reducing a sum of conduction loss and driving power of the switching element.

Driving device and method of switching element in power conversion apparatus using current-controlled semiconductor switching element

A switching circuit for a power conversion apparatus capable of reducing conduction loss to provide a higher efficiency, and achieving downsizing and weight-reduction and higher driving frequency based on the improved efficiency is disclosed. A driving transistor is connected to a switching main transistor to supply a driving power for ON-OFF driving thereto, and an auxiliary power source composed of a current transformer is provided between the main transistor and the driving transistor. An auxiliary transistor having a lower switching loss than that of the main transistor is connected in parallel with the main transistor to form a main switch in combination with the main transistor. A current-driven type transistor serves as the main transistor, and voltage-driven type transistors serve as both of the driving transistor and the auxiliary transistor. The auxiliary transistor is adapted to be driven at a higher speed than that of the main transistor when the main transistor is turned on, and adapted to be driven at a lower speed than that of the main transistor when the main transistor is turned off.

Switching circuit of power conversion apparatus

In a power conversion device including a current control semiconductor switching element, a driving device of the aforementioned switching element is disclosed. The driving device comprises an output main line connected to a base or gate of the switching element, an output return line connected to an emitter or source. A collector current detecting device for detecting a collector current or drain current, and a base current control device for controlling a base current or gate current are provided. The base current control device controls the base current to reduce the sum of conduction loss and drive power in the switching element in accordance with a collector current signal from the collector current detecting device.

Driving device of switching element in power conversion device using current control semiconductor switching element

A magnetic sensor apparatus comprises a magnetic detector (,) that outputs a signal responsive to a magnetic field and a magnetic substance (,) having a cavity (,) in which the magnetic detector (,) is placed. The magnetic detector (,) is placed in the cavity (,) of the magnetic substance (,). The ratio between a magnetic field (H) to be measured and a magnetic field applied to the magnetic detector (,) is set to a specific value, based on at least one of a first demagnetizing factor depending on the shape of the magnetic substance (,) and a second demagnetizing factor depending on the shape of the cavity (,). The magnetic sensor apparatus further comprises a feedback coil (,) that applies a negative feedback magnetic field to the magnetic detector (,) and a reference magnetic field coil (,) that applies a reference alternating magnetic filed to the magnetic detector (,) for controlling the property of the magnetic detector (,).

Magnetic sensor apparatus, current sensor apparatus and magnetic sensor element

It is an object of the invention to provide a magnetic sensor and a current sensor that exhibit high performance at low costs. A magnetic sensor has a magnetic core (,) having a magnetic saturation property and a sensor coil (,) wound around the magnetic core (,). An end of a detection coil (,) is connected to an end of the sensor coil (,). The other end of the detection coil (,) is grounded. The magnetic sensor further comprises a drive circuit (,) and a detection circuit (,). The drive circuit (,) has a series resonance circuit part of which is made up of the sensor coil (,). To the sensor coil (,) the drive circuit (,) supplies a resonance current flowing into the series resonance circuit as an alternating current that allows the magnetic core (,) to reach a saturation region. The detection circuit (,) detects a magnetic field to be measured by detecting variations in resonance current flowing through the sensor coil (,).

Magnetic sensor apparatus and current sensor apparatus

This PWM inverter apparatus includes a first and second current control type semiconductor switching elements connected in series which are connected in parallel to a DC power supply. An output is generated by alternately switching the first and second semiconductor switching elements. Resistive semiconductor switching elements having a higher switching speed than the first and second semiconductor switching elements and a resistance-to-current characteristics producing a voltage drop are respectively connected in parallel to respective the first and second semiconductor switching elements. In a half cycle of an alternating output current, while the output current is higher than a predetermined rate with respect to a peak current, a switching timing is controlled to produce a switching control signal to the resistive semiconductor switching elements ahead of a switching control signal to the first and second semiconductor switching elements, and to terminate the switching control signal to the resistive semiconductor switching elements at a time when a predetermined period passes after the switching control signal given to the first and second semiconductor switching elements has been terminated. In the half cycle of the alternating output current, while the output current is lower than the predetermined rate with respect to the peak current, the switching timing is controlled to generate the output by the switching operation only of the resistive semiconductor switching elements.

PWM inverter apparatus

The present invention provide a partial resonance PWM converter capable of making the switching loss occurring at a switch approximately zero and high efficiency by controlling a switching timing. A series circuit composed of upper and lower main switches is connected in parallel with a DC power supply, and diodes are respectively connected in parallel with each of the main switches in the opposite direction of a polarity of the DC power supply. A series circuit composed of upper and lower auxiliary switches is connected in parallel with the DC power supply, and diodes are respectively connected in parallel with each of the auxiliary switches in the opposite direction of the polarity of the DC power supply. A series resonance circuit composed of a capacitor and an inductor is inserted between the juncture of the upper and lower main switches and a juncture of the upper and lower auxiliary switches. The switching timing is controlled to make the auxiliary switch turn on just before the main switch is switched, to make the main switch turn off during the diode connected in parallel with each of the main switches is in ON condition, and to make the auxiliary switch turn off during the ON condition of the diode connected in parallel with each of the auxiliary switches.

Partial resonance PWM converter

The electric power conversion device includes an AC section, a DC section, a switching section connected between the AC section and the DC section for making power conversion by switching operation, and a control section for control the switching section. In the DC section is installed a ripple detection device for detecting a ripple component emerging into the DC side and for generating a ripple detection signal. When the DC component is included in the output current of the AC section, a ripple component having the same frequency with the AC frequency of the AC section output current is superimposed in the DC section. The ripple detection device is installed in the DC section, and thereby the ripple component emerging into the DC section is detected by the ripple detection device as a reflection of the DC offset included in the output current. The control section receives the ripple detection signal from the ripple detection device, generates the DC component compensation signal for controlling the DC component included in the AC side current based on the ripple detection signal, and controls the switching section by the control signal including the DC component compensation signal to compensate the DC offset.

Electric power conversion device

A bi-polar transistor structure in a superhigh speed logic integrated circuit, and a process for producing the same are disclosed. The transistor has a substantially coaxial symmetric structure. Single crystal active layers as base and collector regions have peripheries surrounded wholly or partially by respective polycrystalline electrode layers. The polysilicon electrodes have lateral portions and downward depending portions that connect to single crystal layers. The polycrystalline electrode layers are separated from each other by insulation. One process for producing the structure uses only thin film forming techniques and etching techniques to dispose the active layers, an emitter electrode layer, parts of the other electrode layers and parts of the insulating layers inside a recess formed in an insulating layer formed on a substrate. Another process uses a photoetching technique by which polycrystalline layers for base and collector electrodes are patterned. Around the patterned polycrystalline electrode, side wall insulating layers are formed in the respective later steps.

Process for forming bipolar transistor structure

Method for fabricating a semiconductor device

Bi-polar transistor structure

In method of fabricating a bipolar transistor on a semiconductor substrate, the emitter pattern is formed using the horizontal etching effect and filling-in effect of the RF-bias sputtering method, so a fine, self-aligned emitter pattern can be created that is disposed entirely in the center of the active base region without the use of photoetching. In addition, the passive base layer and the emitter layer can approach each other to any desired degree as long as they do not touch, so no high-concentration base layer is necessary, the base resistance is reduced, and the passive base region is reduced to a very small size. Furthermore, after the formation of the base region, the only heat treatment step that alters the diffusion layer profile is the formation of the emitter layer, so the use of a thin epitaxial layer to reduce the collector resistance does not result in proximity of the buried collector layer and the passive base layer.

Fabrication method for semiconductor integrated circuits

In a process of fabricating a semiconductor IC having a plurality of metal wiring conductor layers on a semiconductor substrate and an insulation layer between the metal wiring conductor layers, the insulation layer being formed of a silicon oxide film is formed by means of RF bias-sputtering, a silicon oxide film is formed by means of RF bias sputtering under such a condition that the deposition rate and the etching rate on a pattern surface 45.degree. inclined with respect to the reference surface of the semiconductor substrate are equal, part of the silicon oxide film over the underlying metal wiring conductor layer being protruded; a trench is formed in part of the silicon oxide film covering the metal wiring conductor layer, and the silicon oxide is etched by RF bias sputtering under such a condition that the deposition rate and etching rate on a pattern surface parallel to the reference surface of the semiconductor substrate are equal, until the protrusion of the silicon oxide film over the metal wiring conductor is removed so that the entire silicon oxide film is planarized.

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Tokyo, Japan

Yoshihisa Okita