423results about How to "Reduce withstand voltage" patented technology

An LED driving circuit is used for dimming by switching between an operating current and a maintaining current or by voltage clamping of a source / drain of MOSFET that is coupled to the LED module. When the LED module is dimmed off, the voltage across the LED module can be kept at a value around a lighting threshold voltage of the LED module that is a minimum voltage for lighting the LED module. Therefore, a voltage difference between the drain and the source of MOSFET coupled to the LED module is smaller than that in the conventional arts. Hence, a withstand voltage of MOSFET can be reduced, and cost of the LED driving circuit as well as the power consumption of MOSFET can be lessened, thereby improving integral efficiency of the circuit.

A drive unit for driving multiple groups of light emitting elements operable at different voltages, though the drive unit is adapted to operate the different groups by means of a step-up circuit providing a low voltage. The inventive step-up circuit steps up a power source voltage (Vcc) to a predetermined positive voltage (Vp), which is inverted to a negative voltage (Vn) by an inverted voltage generating circuit. A first light emitting element group (first LED group) operable at a low voltage is by the positive voltage (Vp), with low necessary voltage emit light on positive voltage and grand voltage, while a second light emitting element group (second LED group) operable at a higher voltage is driven by a combination of the positive voltage (Vp) and the negative voltage (Vn). Thus, energy loss in the drive unit is reduced, thereby improving the operating efficiency of the drive unit.

A p well serving as a channel region of a MOSFET is formed on one side of an n− layer and an n+ drain region is formed on the other side. Above the n− layer, a plurality of first floating field plates are formed with a first insulating film interposed therebetween. A plurality of second floating field plates are formed thereon with a second insulating film interposed therebetween. Assuming that the thickness of the first insulating film is “a” and the distance between the first floating field plates and the second floating field plates in a direction of thickness of the second insulating film is “b”, a relation a>b is held.

An abnormal voltage detection apparatus is provided for an assembled battery including a plurality of battery blocks connected in series to each other. In the abnormal voltage detection apparatus, each of a plurality of signal detectors is provided in each of battery blocks. Each of the signal detectors detects voltage abnormality or normality in each battery block based on a voltage of each battery block, generates an abnormality detecting signal containing information about the detected voltage abnormality or normality, and outputs the abnormality detecting signal. A signal generator generates an abnormality detecting information signal containing information about whether or not any of the battery blocks in the voltage abnormality is present based on the abnormality detecting signals. A transmission device has an input terminal pair and an output terminal pair which are electrically insulated from each other, and transmits the abnormality detecting information signal to an external apparatus.

A direct-current power supply connecting the negative pole bus of an inverter circuit and the neutral point of a motor and a capacitor connecting the positive pole bus of the inverter circuit and the neutral point of the motor are provided for performing the switching control of the transistors T1-T6 of the inverter circuit on the basis of a phase voltage command value formed by the addition of a direct-current component and an alternating-current component. The voltage between the terminals of the capacitor is controlled on the direct-current component, and the driving control of the motor is performed on the alternating-current component. The supply voltage of the direct-current power supply can be made to be lower than a voltage necessary to drive the motor. Moreover, the withstand voltage of the capacitor can be made to be smaller and the relay circuit can be simplified in comparison with an apparatus equipped with a capacitor connected between the positive pole bus and the negative pole bus of an inverter circuit. As a result, the downsizing of an apparatus and the reduction in costs can be achieved, and the durability and the reliability of the apparatus can be improved.

A PDP driving circuit is comprised of a power recovery unit for recovering an electric power from a capacitive load by resonance operation with PDP which is the capacitive load Cp, and reusing the recovered power. The power recovery unit includes a recovery inductor for resonating with the capacitive load, a recovery switch element for connecting the recovery capacitor to the capacitive load and recovery inductor, and forming a channel for passing resonance current, a counterflow preventive diode for blocking flow of current in the recovery switch element in reverse polarity direction, and a protective diode for forming a closed current channel including the recovery inductor and recovery switch element when the counterflow preventive diode is changed from ON state to OFF state.

An electro-optical device includes a thin-film transistor in each of a plurality of pixel regions on an element substrate, the thin film transistor including a gate electrode, a gate insulating layer disposed above the gate electrode, and a semiconductor layer disposed above the gate insulating layer, a pixel electrode that is electrically connected to a drain region of the thin-film transistor, and a storage capacitor including a lower electrode and an upper electrode, the lower electrode and the upper electrode facing each other, the gate insulating layer being disposed between the lower electrode and the upper electrode. The gate insulating layer including a lower gate insulating layer having one or a plurality of insulating films, and an upper gate insulating layer having one or a plurality of insulating films. The lower gate insulating layer having a thickness sufficient to reduce parasitic capacitance of the thin-film transistor, and a portion of the lower gate insulating layer being removed where the lower electrode and the upper electrode overlap each other.

An electric leakage detecting apparatus, in an electric leakage detecting apparatus which is insulated from a chassis ground and detects electric leakages of a battery, is provided with: a voltage dividing circuit that divides an output voltage of the battery; an electric leakage determining circuit provided at a rear stage of the voltage dividing circuit, that determines the presence of an electric leakage based on a voltage detected by a circuit that respectively connects to a positive electrode side insulation resistance or a negative electrode side insulation resistance of the battery; and a dark current inhibit circuit in which a switch and a resistance are connected in parallel, that is inserted between at least either one of wiring that connects a positive terminal of the battery and the voltage dividing circuit, and wiring that connects a negative terminal of the battery and the voltage dividing circuit.

Capacitors are connected in series between a first DC link section and a second DC link section when the capacitors are charged by a regenerative current derived from an inverter section. During discharge, as first, second switching circuits turn on, the capacitors are discharged with those capacitors connected in parallel between a first DC link section and a second DC link section.

One aspect according to the present invention includes an electric power tool, in which a capacitor is positioned closer to a motor control circuit than a switch electrically connected to the motor control circuit.

The present invention provides a semiconductor device which reduces an inductance of wiring for bridge-connecting semiconductor switches and realizes a reduction in size. Within the semiconductor device formed are two controllable bridge-connected semiconductor switches 13a and 13b, an output terminal, positive / negative polarity DC terminals 2 and 3, and an insulating substrate 15a in which conductor layers 12, 17 and 19 having a conductor section and in an inner layer for bridge-connecting the semiconductor switches to the DC terminals on a surface thereof and insulating layers 16 and 18 are alternately laminated. The surface and inner-layer conductor layers 12 and 17 which interpose the insulating layer 16 therebetween are electrically connected by a conductor 20 passing through the insulating layer 16 interposed between the conductor layers 12 and 17. A current path (dotted line) is so provided as to allow current flowing through a bridge circuit for mounting the two semiconductor switches on the insulating substrate to flow in opposite directions between the conductor layers 12 and 17 which interpose the insulating layer 16 therebetween.

In one embodiment, a method is disclosed for producing a composite magnetic material, wherein the non-magnetic binder comprises a layered compound having an insulation property and the non-magnetic binder and soft magnetic metal powder is admixed with each other, the admixture is compacted to a desired shape, and the compact is heat-treated under predetermined condition to form a thin insulating layer made of the insulating layered compound on the surface of the soft magnetic metal powder, thereby producing the composite magnetic material having a withstand voltage of 20 V or more.

The invention discloses a hybrid direct-current transmission topology structure and a control method. The hybrid direct-current transmission topology structure is characterized in that two groups of thyristor converters are connected in series to form a first converter station, two groups of voltage source type converters are connected in series to form a second converter station, switch elements are respectively mounted at the same positions of the positive ends and the negative ends of the converters, in series connection, of the first converter station or the second converter station or the first converter station and the second converter station, and meanwhile, the same positions of the positive ends and the negative ends of the converters are in parallel connection and crossly connected to the opposite ends through one switch element respectively. The control method includes reducing direct-current power of a direct-current system to zero, and changing states of the switch elements to invert voltage polarity of the direct-current system, thereby achieving overall operation of two poles after inversion of the direct-current voltage polarity or achieving new two-pole direct-current operation by means of crossing of the converters in series connection of the converter stations at both ends. The system of the hybrid direct-current transmission topology structure has advantages of low manufacturing cost as the conventional direct-current transmission and control flexibility as the flexible direct-current transmission, and the like.

The power IC includes an output transistor MO which controls a current flowing into an L load, a dynamic clamp circuit which clamps an overvoltage, and a clamp control circuit which controls the operation of the dynamic clamp circuit. The clamp control circuit activates the dynamic clamp circuit, which is normally inactive, upon detection of a back EMF by the L load.

The invention relates to an active power quality adjuster, consisting of a fundamental wave compensation part and a harmonic wave compensation part, and the two parts compensate fundamental current and harmonic current respectively. An H-bridge cascade multilevel inverter and a fundamental wave connection inductance are connected in series at the fundamental wave compensation part, so that reactive compensation and unbalanced load compensation can be dynamically carried out; the H-bridge cascade multilevel inverter and a unituning passive filter are connected in series to form the harmonic wave compensation part which is connected across the two ends of the fundamental wave connection inductance. Therefore, the power quality adjuster can lower switching frequency and loss of the H-bridge cascade multilevel inverter at the fundamental wave compensation part greatly on one hand, and only a fraction of fundamental current passes the harmonic wave compensation part and the whole part only undertakes fundamental voltage of the fundamental wave connection inductance without undertaking fundamental voltage on the other hand, thereby effectively reducing the capacity of the H-bridge inverter and the withstand voltage at the harmonic wave compensation part.

A power supply circuit for a gate driving circuit for driving semiconductor switching devices of a power converter that is configured to perform a DC to AC conversion. The power supply circuit includes a DC power supply including a plurality of serially-connected single DC power supplies, a flying capacitor type power conversion circuit including a plurality of flying capacitors connected in parallel to a plurality of the semiconductor switching devices, and a plurality of serially-connected circuits each having an insulating device, a middle part of the series-connected circuits being connected to a middle potential point of the flying capacitors, and to a fixed potential point of the DC power supply.

Provided in the invention is a flexible multi-state switch comprising a first isolation transformer (T1), a first controlled voltage source (D11), a direct-current bus voltage-stabilizing capacitor (C1), a second controlled voltage source (D22), a second isolation transformer (T2), and a central controller. A first feeder line (K11) is connected to the first controlled voltage source (D11) throughthe first isolation transformer (T1); a second feeder line (K22) and the second controlled voltage source (D22) ) are connected by the second isolation transformer (T2); and the first controlled voltage source (D11) is connected to the second controlled voltage source (D22) through the direct-current bus capacitor (C1). Various functions including bidirectional circulation of active power betweenfeeder lines, reactive compensation control, short-circuit current suppression, power flow optimization and power quality management and the like are realized by applying different control methods onthe first controlled voltage source (D11) and the second controlled voltage source (D22) of the flexible multi-state switch.

An inverter transformer includes: a frame-core shaped substantially square; a plurality of I-cores disposed inside and coupled to the frame-core so as to provide a predetermined leakage inductance; and a plurality of primary and secondary windings provided respectively around the I-cores. The I-cores are divided into first group cores located not adjacent to one another and second group cores located not adjacent to one another but adjacent respectively to the first group cores. Magnetic fluxes generated in the first group cores flow in the same direction, magnetic fluxes generated in the second group cores flow in the same direction that is opposite to the direction of the magnetic fluxes generated in the first group cores, and respective voltages induced at secondary windings provided respectively around the first and second group cores are polarized identical with each other.

In a disclosed excess voltage protection circuit, when the input voltage equal to or higher than a predetermined maximum voltage is detected by an excess voltage detection circuit, a switching element is shut off so as to prevent the input voltage being output from the excess voltage protection circuit. A voltage obtained by dividing the input voltage using resistors is output from the excess voltage protection circuit.

A semiconductor device 1 in which an IGBT region 2 and a diode region 3 adjoining each other are formed on a same substrate 4 is presented. The semiconductor device 1 is provided with a plurality of first gate trenches 11 extending abreast in a first direction in the IGBT region 2 and a plurality of second gate trenches 12 extending abreast in a second direction intersecting the first direction. The first gate trenches 11 and the second gate trenches 12 are not in contact with each other.

An AC to DC converter is provided with: a rectifier circuit that rectifies an AC voltage generated by an AC voltage source; and a plurality of switching units that collectively receive an output voltage of the rectifier circuit through an inductor, and that are connected in series at an input side, each of the switching units having a semiconductor switching device, a diode, and a capacitor, and performing ON / OFF switching of the semiconductor switching device provided therein to step up a voltage received from the rectifier circuit, each of the switching units supplying the stepped-up voltage to the capacitor through the diode so that a resulting DC across the capacitor can be provided, as a DC output voltage of the switching unit, to a respective load to be connected to terminals of the capacitor.

The invention provides an interleaved parallel magnetic-integration bidirectional full-bridge LLC resonant converter and relates to the technical field of power and electronic applications. The interleaved magnetic-integration bidirectional full-bridge LLC resonant converter comprises two paths of an interleaved parallel bidirectional full-bridge LLC resonant converter. The first path of the bidirectional full-bridge LLC resonant converter comprises a first primary-side circuit, a first secondary-side circuit, a resonant transformer and a magnetic inductor thereof. The second path of the bidirectional full-bridge LLC resonant converter comprises a second primary-side circuit, a second secondary-side circuit, a resonant transformer and a magnetic inductor thereof. The primary-side circuit and the secondary-side circuit of each path of the bidirectional full-bridge LLC resonant converter are respectively in the form of a full-bridge LLC resonant circuit and are used for realizing the bidirectional energy flow. The two resonant transformers, the magnetic inductors thereof and four resonant inductors of the two paths of the interleaved parallel bidirectional full-bridge LLC resonant converter are magnetically integrated through integrated magnetic pieces. According to the technical scheme of the invention, the large-power, high-transformation-ratio, small-volume, bidirectional and high-efficiency operation of the electric energy is realized.

A reset pulse generating section applies the total of voltages of a positive voltage source and two constant-voltage sources from a high side ramp wave generating section to a high side scan switching device as the upper limit of a reset voltage pulse, and applies the ground potential from a low side ramp wave generating section to a low side scan switching device as the lower limit of the reset voltage pulse. A sustaining pulse generating section applies the upper and lower limits of a sustaining voltage pulse through a common sustaining pulse transmission path to the low side scan switching device.

A semiconductor device which eases an electric field at a drift portion without a reduction in impurity concentrations, and has a high withstand voltage and a low on-resistance, wherein, when a rated voltage is applied between a body region and a drain region formed on an insulating semiconductor substrate, the thicknesses of two, p-type and n-type, drift regions sandwiched between the body and drain regions are selected so as to completely deplete the drift regions.

A switching power supply unit is provided, in which a DC input voltage can be detected even if switching operation of the power supply unit is stopped. A switching power supply unit includes: a power supply main section switching a DC input voltage inputted from a first power supply to convert the DC input voltage into an AC voltage, and outputting a DC output voltage into a second power supply, the DC output voltage being obtained by transforming and rectifying the AC voltage; and a voltage detection section having a voltage detection transformer, one or more switching elements, and detection signal lines. The voltage detection transformer includes a first transformer coil as a primary winding being intermittently applied with the DC input voltage in response to on / off of the switching element, and a second transformer coil as a secondary winding being connected to the detection signal lines.

The invention discloses a start-up circuit with a high-tension power supply, and the start-up circuit comprises a power resistor, an voltage-regulator diode, a current-limiting resistor, an MOS (metal oxide semiconductor field effect transistor) and a filter capacitor, wherein, the negative pole of the voltage-regulator diode is connected with the grid of the MOS, the positive pole of the voltage-regulator diode is connected with the negative pole of an input voltage, the grid of the MOS is connected with a drain through the power resistor and the current-limiting resistor, the source electrode of the MOS is connected with one end of the filter capacitor, the other end of the filter capacitor is connected with the negative pole of the input voltage, the two ends of the filter capacitor are the output ends of the start-up circuit, and the start-up circuit with the high-tension power supply also comprises a capacitor voltage division circuit which consists of at least two stages of voltage division capacitors connected in series; and the capacitor voltage circuit is connected between the positive pole and negative pole of the input voltage in parallel, one end of the last-stage voltage division capacitor is connected with the negative pole of the input voltage, the other end of the last-stage voltage division capacitor is connected with connections of the current-limiting resistor and the power resistor. The start-up circuit provided by the invention has advantages of less loss, high reliability and low cost.

A ceramic electronic component includes a component body having semiconductive ceramic layers and internal electrodes. The semiconductive ceramic layers and the internal electrodes are alternately laminated. The semiconductive ceramic layers have a relative density of about 90% or less and contain no sintering additives. The component body is provided with an external electrode on each side thereof. The ceramic electronic component has a low resistance and a high withstand voltage.