418results 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.

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.

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 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.

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.

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.

An interleaved flyback converter device with leakage energy recycling includes: two flyback converters and an input power. Each flyback converter includes a capacitor, a switch, two diodes, and a transformer. The input power is connected to the capacitors of the two flyback converters respectively. By using the capacitors as input voltage, the two flyback converters are provided with lower voltage rating. The diodes are used to recycle leakage energy directly, and to clamp voltage on power components. Therefore, in addition to enhancing efficiency via recycling leakage energy, the two flyback converters have lower switching losses due to lower switching voltage.

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.

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.