995 results about "Flyback diode" patented technology

A semiconductor switch is provided with a main element having reverse conductivity and serving as a voltage-driven switching element having a high withstand voltage, an auxiliary element serving as a voltage-driven switching element having a withstand voltage lower than that of the main element, and a high-speed freewheel diode having a withstand voltage equal to that of the main element, wherein a negative pole of the main element is connected to a negative pole of the auxiliary element to define the positive pole of the main element as a positive pole terminal and the positive pole of the auxiliary element as a negative pole terminal, and the high-speed freewheel diode is parallel-connected between the positive pole terminal and the negative pole terminal so that a direction from the negative pole terminal toward the positive pole terminal constitutes a forward direction.

In an IGBT with a built-in freewheeling diode, a thickness (D) of a polished wafer is equal to 200 μm or smaller, and each of respective thicknesses (T8) and (T9) of an N+-type cathode layer (8) and a P+-type collector layer (9) is equal to 2 μm or smaller. Further, a total width of the N+-type cathode layer (8) and the P+-type collector layer (9) which extends along a width direction (X) is in a range from 50 μm to 200 μm. In this case, an interface (IF2) between a collector electrode (10) and the P+-type collector layer (9) occupies 30-80% of an interface (IF) between the collector electrode (10) and the P+-type collector layer (9) plus the N+-type cathode layer (8).

This invention relates to a voltage-boosting type active staggered parallel-connection soft switching circuit. It comprises: two phase coupled inductors, two follows current diodes, two power switching tubes. The drain electrode of the first power switching tube, the positive pole of the second diode and one end of the second inductor are connected. The drain electrode of the second power switching tube, the positive pole of the fist diode and one end of the first inductor are connected. The other end of the first inductor and second inductor are connected. The first power switching tube is paralllet connected with a series circuit composed of the first capacitor and the first auxiliary switching tube; while the second power switching tube is parallel connected with a series circuit composed of the second capacitor and the second auxiliary switching tube. Advantages are: less auxiliary devices, simple structure, no need of additional testing.

A semiconductor device includes a vertical IGBT and a vertical free-wheeling diode in a semiconductor substrate. A plurality of base regions is disposed at a first-surface side portion of the semiconductor substrate, and a plurality of collector regions and a plurality of cathode regions are alternately disposed in a second-surface side portion of the semiconductor substrate. The base regions include a plurality of regions where channels are provided when the vertical IGBT is in an operating state. The first-side portion of the semiconductor substrate include a plurality of IGBT regions each located between adjacent two of the channels, including one of the base regions electrically coupled with an emitter electrode, and being opposed to one of the cathode regions. The IGBT regions include a plurality of narrow regions and a plurality of wide regions.

An illumination system includes a power supply having a boost converter operating in the discontinuous conduction mode, a flyback converter operating in the critical conduction mode, and a switch coupled to the flyback converter. Several light emitting diodes receive power from the power supply. The boost converter may include a boost inductor (LB) and a boost diode (DB), constructed to perform the boost power factor correction (PFC) function. The flyback converter may includes a flyback inductor (LFB) and a flyback diode (DFB) and the power supply may be constructed to turn on the switch around the point where the current flowing in the flyback inductor reaches zero value.

An organic light emitting display having a DC-DC converter with freewheel diodes replaced by switches integrated into a switching controller. This way, power consumption is reduced by truly shutting down a current path when the DC-DC converter does not operate, and the size and weight of the DC-DC converter may be reduced. One embodiment of the DC-DC converter has a boost converter with a first switch coupled to a power supplier and a second switch, functioning as a freewheel diode, coupled to an organic light emitting display panel, and an inverter with a third switch coupled to the power supplier and a fourth switch, functioning as a freewheel diode, coupled to the organic light emitting display panel. A switching controller is coupled to the boost converter and the inverter. The second and fourth switches, which function as the freewheel diodes, are integrated into the switching controller.

A circuit device includes at least one switching element and a free wheeling diode connected in parallel to the switching element. The free wheeling diode is made up of a Schottky barrier diode using a semiconductor material having a band gap larger than silicon as its base material and also a silicon PiN diode, which are connected in parallel. The Schottky barrier diode and the silicon PiN diode are provided in the form of separate chips. A circuit system is also provided wherein a diode having a Schottky junction of a compound semiconductor as a rectification element built therein is combined, and a relationship, R2>4L / C, with impedance R (resistance), L (inductance), and C (capacitance) determined by a closed circuit between a power source and a positive or negative terminal when the current of the diode becomes zero during recovery operation, is satisfied.

An inverter circuit (120) is configured so as to perform synchronous rectification by six switching elements (130). The switching element (130) is formed of an unipolar device (SiC MOSFET in this case) using a wideband gap semiconductor. The inverter circuit (120) uses the body diode (131) of SiC MOSFET (130) as a freewheeling diode during synchronous rectification.

The invention relates to a transcranial magnetic field stimulator with a plurality of stimulating coils which comprises a high voltage charging power supply, a current-limiting resistance, an energy dumped capacitor, a reverse current reflowing diode, a thyristor switch, stimulating coils and a microcomputer controller. The stimulator is characterized in that: a stimulating unit comprises a thyristor switch, a stimulating coil and an energy dumped capacitor; N parallel connected stimulating units are connected to the current-limiting resistance and the high voltage charging power supply end; N stimulating units shared use an energy dumped capacitor; the microcomputer controller ends are respectively connected with the triggering ends of the thyristor switch in every stimulating unit; N is more than or equal to 2. A magnetic field stimulator of the invention can substitute a plurality of magnetic field stimulators in using, realizes the in-turn stimulation of a plurality of stimulating coils, and ensures a plurality of parts to get continuous stimulation from the program control. If the number of the energy dumped capacitor is increased, a plurality of coils not only can be stimulated in time sharing, but also achieving synchronous stimulation and couple stimulation.

The invention provides a switch reluctance motor double master switch power converter master switch fault diagnosis method. A current sensor LEM1 is arranged on the master switch current circuit (DC)busand and is used for testing the total current of the main switch on the DC bus, a current sensor LEM2 is arranged on the free-wheeling diode DC bus and is used for testing the total current feedback by the free-wheeling diode on the DC bus, the wires of the two current sensors are connected with a receiver to obtain the total current signal of the master switch and the total current signal fedback by the free-wheeling diode. The invention can be used for judging that short trouble occurs to both the upper master switch tube and the lower master switch tube and open fault occurs to both theupper main switch tube and the lower main switch tube, and can be used for carrying out fault location, thus having convenient fault-tolerant control, and wide application prospects.

A current sense and feedback circuit is provided for a non-isolated Buck power converter to maintain constant current load regulation. The Buck converter may have a high side power switch and may include an input port, a switcher unit including a switch and a controller, an inductor coupled to the output, and a freewheeling diode for circulating the inductor current when the switch is open. The simplified current sense and feedback circuit of the power converter may include a current sense resistor module coupled to the freewheeling diode to provide a sense signal to the controller. The controller may also be coupled to the output of the power converter to sense an over voltage condition. The simplified current sense and feedback circuit may provide output regulation while maintaining a low component count, small size, and low loss that makes the power converter suitable for use in compact design applications.

In known converter circuits switching losses occur, which are caused by reverse-recovery currents of a freewheeling diode. To reduce said switching losses it is proposed by the invention to drive the switching elements such that, upon switching from the second to the first switching element, the timing is controlled in such a manner that the shoot through currents and the conduction of the freewheeling diode are kept at a low value or, better still, are precluded. As regards the control mechanism, it is proposed to turn on the first switching element later if shoot through currents occur, and to turn on the first switching element sooner if conduction of the freewheeling diode occurs. Here, a time of overlap may be provided during which both switching elements are simultaneously conducting. For the control mechanism, the voltage across a switching element can be used as a measured input value.

The invention discloses an electromobile range extender and a control method. The electromobile range extender consists of an engine, an engine ECU (Electronic Control Unit), an electronic throttle valve controller, a direct current starter, an engine speed sensor, an alternating current permanent magnet synchronous motor, a three-phase full-control rectifier, filter capacitors, voltage sampling resistors, a current sensor, a freewheeling diode and a three-phase full-control rectifying voltage regulation phase-shift trigger, wherein the engine is started by the starter and then drags the alternating current permanent magnet synchronous motor to generate electricity and output the three-phase alternating current voltage to the thyristor three-phase full-control rectifier; after the direct current pulsating voltage output by the rectifier is filtered by the two filter capacitors connected in series, the three-phase full-control rectifying voltage regulation phase-shift trigger acquires the output voltage and current of the range extender to obtain the output power, and adjusts a conduction angle according to the power to realize closed-loop control of the power; and the electronic throttle valve controller acquires the engine speed, adjusts the throttle valve opening, and realizes the closed-loop control of the engine speed. The electromobile range extender and the control method have the advantages of low cost and high control precision.

The invention provides a light-emitting diode (LED) switch constant-current driving circuit. The LED switch constant-current driving circuit comprises a voltage input module, an energy storage inductor, a freewheel diode, an LED module serving a load, a power tube for draining current and constant current, a detection module for detecting an input voltage phase state, a dimming control module connected to the detection module, an error amplifier connected to the dimming control module, a valley bottom detection circuit for detecting power tube drain voltage, a pulse width modulation circuit connected to the error amplifier and the valley bottom detection circuit, a control circuit for controlling the power tube according to detection voltage and PWM signals and a driving circuit of the power tube, wherein according to the dimming control module, input reference voltage Vref2 of the error amplifier and dimming control signals Vdimo are generated jointly through the detection voltage and reference voltage Vref1; the error amplifier enables the Vref2 to be compared with sampling voltage; and the pulse width modulation circuit is used for generating the PWM signals. According to the LED switch constant-current driving circuit, an electrolytic capacitor is not needed, an electronic transformer and a silicon controlled dimmer are compatible, the unique power tube in multiplexing simultaneously gives consideration to the draining current and the constant current, and the cost is effectively reduced.

A reverse-conducting semiconductor device is disclosed with an electrically active region, which includes a freewheeling diode and an insulated gate bipolar transistor on a common wafer. Part of the wafer forms a base layer with a base layer thickness. A first layer of a first conductivity type with at least one first region and a second layer of a second conductivity type with at least one second and third region are alternately arranged on the collector side. Each region has a region area with a region width surrounded by a region border. The RC-IGBT can be configured such that the following exemplary geometrical rules are fulfilled: each third region area is an area, in which any two first regions have a distance bigger (i.e., larger) than two times the base layer thickness; the at least one second region is that part of the second layer, which is not the at least one third region; the at least one third region is arranged in the central part of the active region in such a way that there is a minimum distance between the third region border to the active region border of at least once the base layer thickness; the sum of the areas of the at least one third region is between 10 and 30% of the active region; and each first region width is smaller than the base layer thickness.

A flyback LED drive circuit for the plurality of LEDs is provided. An inductive device is coupled to an input voltage. A power transistor is connected to the inductive device in series to control the switching current of the inductive device. The energy is stored into the inductive device when the power transistor is turned on. The stored energy is delivered to the plurality of LEDs via a flyback diode when the power transistor is turned off. A control circuit is utilized to detect the switching current of the inductive device for generating a switching signal to provide a constant current to the plurality of LEDs.

The invention discloses a passive and nondestructive clamping single-phase high-gain converter, which comprises a coupling inductor. The first end of a first winding of the coupling inductor is connected with the anode of a power supply; the second end of the first winding is connected with the drain electrode of a power switch tube and the anode of a clamping diode; the cathode of the clamping diode is connected with the first end of a clamping capacitor; the source electrode of the power switch tube is connected with the cathode of the power supply; one end of a second winding of the coupling inductor is connected with the anode of a fly-wheel diode and the cathode of the clamping diode; the second end of the second winding is connected with the first end of a double-voltage capacitor; the second end of the double-voltage capacitor is connected with the cathode of the fly-wheel diode; the first end of the second winding of the coupling inductor and the first end of the first winding of the coupling inductor serve as same name ends of the coupling inductor; the anode of an output diode is connected with the cathode of the fly-wheel diode; the cathode of the output diode is connected with the first end of an output capacitor; and the second end of the output capacitor is connected with the cathode of the power supply.

A power semiconductor module (1) includes a first MOS transistor (16) connected to a positive side power supply terminal via a first conductor pattern (11), a first free wheeling diode (17) connected to the positive side power supply terminal via a second conductor pattern (12), a second MOS transistor (18) connected to a negative side power supply terminal via a third conductor pattern (13), and a second free wheeling diode (19) connected to the negative side power supply terminal via a fourth conductor pattern (14). These semiconductor elements (16-19) are connected to a load side output terminal via a common fifth conductor pattern (15). The semiconductor element (16, 17) connected to the positive side power supply terminal and the semiconductor element (18, 19) connected to the negative side power supply terminal are arranged alternately, substantially linearly.

An object of the present invention is to reduce the conducting loss of an existing conversion circuit while suppressing its noise. The present invention is typically a circuit arrangement includes at least one switching device and a free-wheel diode connected in parallel with the switching device. The free-wheel diode is formed by connecting a silicon PiN diode in parallel with a Schottky barrier diode that uses a semiconductor material having a wider band gap than silicon as a base material. The silicon PiN diode and Schottky barrier diode are separate chips.

A method is specified for controlling a multiphase motor that is commutated by an inverter-side bridge circuit, in the course of which a particularly precise and technically simple detection of a control-relevant variable of a considered motor phase, in particular of a motor phase current and / or a back EMF voltage and / or a variable derived therefrom, takes place. It is provided here to determine the control-relevant variable with the aid of the current state of a freewheeling diode that is disposed in a phase half bridge, assigned to the respective motor phase, of the bridge circuit, the current state being detected during an on time in which a power switch, connected in parallel with the freewheeling diode, of the phase half bridge exhibits a conducting state, and a power switch connected in series with the freewheeling diode exhibits a blocking state.

The invention relates to a low and medium power high frequency DC-DC converter suitable for high-voltage input, which is based on the fundamental principle that: series capacitors are connected to a high-voltage direct current input, each capacitor serves as an input of the high-frequency forward DC-DC converter, and the outputs of the high-frequency forward DC-DC converter share a filter inductor, a freewheeling diode and an output filter capacitor; voltage feedback is acquired by sampling the output voltage of the high-frequency forward DC-DC converter, and a given reference voltage is compared with the voltage feedback so as to obtain a voltage loop output, namely a main output, by voltage regulation and calculation; and then, high-frequency forward DC-DC converter driving signals which are equational and alternate in phase are acquired to realized the control over a main circuit. The DC-DC converter has the advantages that: a low-voltage switching element is used under high voltage direct current input; the topology is simple; the cost is low; and the output has excellent dynamic and static performance.

This invention discloses active clamp zero-voltage soft switch high gain boost staggered parallel converters including two power switch tubes, two clamp switch tubes, two clamp capacitors, two continuing flow diodes and two coupled inductors, in which, each of the two coupled inductors includes three windings, which utilizes the second and third windings of the two coupled inductors to realize high gain output of the converter, utilizes a serial circuit composed of the two clamp switch tubes and two clamp capacitors to absorb and transfer harmlessly the leak energy of the two coupled inductors and realizes turn on of zero voltage of two power switch tubes and zero voltage turn-off of them utilizing the parallel capacitors of the two switch tubes to further realize zero-voltage turn on and off of the two clamp switch tubes.

The invention discloses a brushless direct-current motor stator flux linkage identification method. The method comprises the following steps: the neutral point of a brushless direct-current motor is grounded to make the voltage of the neutral point clamped to zero; the brushless direct-current motor end voltage is determined through the on-off state of a power tube and a fly-wheel diode during the normal conduction process and the commutation process of a three-phase full-bridge inverter, wherein a three-phase phase voltage is obtained by performing subtraction between the three-phase end voltage and the neutral point voltage; detection is performed by adopting a current sensor to obtain a three-phase phase current, and calculation is performed according to the voltage model of the stator flux linkage to obtain a three-phase stator flux linkage; the three-phase stator flux linkage is filtered by a high-pass filter through CLARK transformation; and vector synthesis is performed on the three-phase stator flux linkage filtered by the high-pass filter to obtain a brushless direct-current motor stator flux linkage. According to the invention, advantages of less required motor parameters, simple structure, less calculation amount and low hardware cost can be realized.

A device and method of commutation control for an isolated boost converter provides a unique commutation logic to limit voltage spikes by utilizing switches on the secondary side to minimize a mismatch between current in the inductor and current in the leakage inductance of the transformer when commutation takes places. To minimize this mismatch, the current in the leakage inductance is preset at a certain level that approaches the current in the inductor prior to the commutation, thus significantly reducing the power rating for a clamp circuit and enabling use of a simple passive clamp circuit. In addition, through unique timing of the turn-on of the secondary switches, soft switching conditions are created that eliminate turn-on losses and the reverse recovery problems of free-wheeling diodes.

The invention discloses an online loss calculation method for a modular multilevel converter (MMC), and belongs to the field of power transmission and distribution. The method comprises the following steps of: 1) calculating the conduction loss of two insulated gate bipolar transistors (LGBT) and two flywheel diodes in each sub-module (SM); 2) calculating the switching loss of the two IGBTs and the reverse recovery loss of the two flywheel diodes in each SM; and 3) calculating related loss by using a loss calculation module. The method has the advantages that: 1, the complexity of manual measurement and calculation is effectively avoided when the MMC has a great number of modules, workload is greatly reduced, and the method is fast and convenient; 2, the online calculation of the loss of the MMC is realized, and the method is wide in application range, and can be applied to the loss calculation of an MMC system in any operating state; and 3, modular packaging is facilitated, a floor area is saved, the utilization rate of resources is increased, and the output of a platform comprises various kinds of loss and loss ratios, so that the method is direct and clear, and staff can conveniently observe the running state of the system at any time.

A system is employed to provide a substantially constant intensity light source via functional circuitry, the functional circuitry comprises a switching power supply. At least one signal is part of a matrix of LEDs connected in series and parallel and configured for redundancy. A monitoring circuit comprises a current sense circuit, wherein the current sense circuit includes an amplifier and at least one resistor in series with the amplifier. The current sense circuit includes a power converter circuit that senses a current of a flyback diode, recovers a dc component of a waveform via a low pass filter, and provides feedback control of the at least one signal.