Abstract: In this power converter, a first capacitor for stepping down of voltage, a first diode for half-wave rectification, and a second capacitor for smoothing are interposed between first and second input connections for input of AC voltage; and a second diode for discharge of the first capacitor is interposed between the second input connection and an input end of the first diode. AC voltage supplied from an AC power supply is divided (stepped down) by the first and second capacitors, rectified to DC voltage by the first diode, smoothed by the second capacitor, and supplied, as an output voltage defined by Zener diodes, to the load side through the first and second output connections.

Abstract: A power converting device includes a power converting unit for converting an AC voltage input into a DC voltage output, a cooling fan for dissipating heat generated by the power converting unit, a detecting unit connected electrically to the power converting unit for detecting a current output of the power converting unit and for generating a control signal corresponding to the current output detected thereby, and a controller connected electrically to the cooling fan and the detecting unit for controlling rotational speed of the cooling fan in accordance with the control signal from the detecting unit.

Abstract: An apparatus and method are disclosed to provide transformerless safety isolation in a power supply. One example regulated power converter includes input terminals included in a primary circuit of the power converter. Output terminals are included in a secondary circuit of the power converter. A plurality of safety capacitors including first and second safety capacitors are also included. Each of the plurality of safety capacitors includes a respective first terminal coupled to the primary circuit and a respective second terminal coupled to the secondary circuit. The plurality of safety capacitors galvanically isolates the primary circuit from the secondary circuit. A power switch is included in the primary circuit. The power switch is coupled such that switching of the power switch causes energy to transfer between the primary and secondary circuits through the plurality of safety capacitors.

Abstract: A power supply (200) is provided having a plurality of independent current limiting circuits. A first current limiting circuit (6) provides protection against a short circuit or other extraneous load conditions, while a second current limiting circuit, using a trace on a PCB as a sensing element, is programmable on the basis of a time constant and a current level.

Abstract: A switching-mode power supply is configured so that two power supply lines are connected with each other via a series circuit consisting of a main switching element, a switch, and a transformer. The switching-mode power supply further includes a ripple voltage detecting circuit for detecting that a ripple voltage in one power supply line has a predetermined amount or more when a half short-circuit occurs in the main switching element. When the ripple voltage detecting circuit detects that the ripple voltage has a predetermined amount or more, the switch is opened so as to block supply of a current (supply of a voltage) to the main switching element. This allows the switching-mode power supply to avoid, with a simple circuit configuration and low costs, being an unstable state when the half short-circuit occurs in the main switching element.

Abstract: The invention relates to an input circuit for a logic circuit part, comprising a voltage converter component for conversion of a mains voltage to the required low voltage in order to supply a user with a low voltage. The supply to the input circuit may hence be connected to a mains supply to rectify the mains voltage and an output from the input circuit may be connected to the voltage converter component to provide a rectified input voltage for the voltage converter component. According to the invention, an improved input circuit for a logic circuit part with improved functionality and operating security also permitting an extensive miniaturization and simplified production may be achieved by replacement of at least two of the remaining four diodes in the rectifier part of an input circuit for a logic circuit part by two controllable switches which work as a synchronous rectifier and are connected such as to be switched on and off by alternate forced control.

Abstract: The present invention discloses a self-excitation synchronous rectification driver, which comprises a self-excitation coil, a self-excitation driver, a synchronous-signal source, a pulse transformer, a positive/negative edge detector, and a latch unit. The synchronous-signal source generates a synchronous signal to attain an external synchronous function. When the frequency is abnormal, the first and second rectifier switches of the rectification unit of the power supply are forced to turn on or turn off. Thereby, the first and second rectifier switches can turn on alternately, and the first and second rectifier switches are limited to within the highest and lowest working frequencies during the zero-load stage or the shutdown stage. Thus, the frequency of the synchronous rectification driver is under control, and abnormal voltage will not occur.

Abstract: An improved snubber is electrically switched to close a current path to a capacitor (C) in a series connected RC circuit at the onset of an abrupt voltage change otherwise producing ringing in a resonant circuit to which the snubber circuit is connected. The current path to the capacitor (C) is then interrupted before the capacitor (C) discharges and thereafter at each such voltage change in the resonant circuit the capacitor (C) is no longer charged from its totally discharged state but nevertheless damps the ringing by virtue of current flow to the nearly completely charged capacitor (C). By preventing complete charging and discharging of the capacitor (C) in the RC circuit every cycle, power dissipation in the resistance of the snubber circuit is greatly reduced.

Abstract: The present invention provides a switching power supply unit and a voltage converting method capable of suppressing a surge voltage applied to an output rectifier element more effectively. Energy in the direction of suppressing reverse voltages (surge voltages) applied to a plurality of rectifier diodes is injected into a rectifier circuit. Reverse voltages applied to the plurality of rectifier diodes are maintained to be lower than a voltage to be inherently applied for a predetermined period. Therefore, rise in the surge voltage is suppressed and rectifier elements (rectifier diodes) having low withstand voltage can be used.

Abstract: The switching power supply apparatus includes detection means for detecting that leak current of an input smoothing capacitor becomes a predetermined value or more and first auxiliary switching means connected in series with respect to the input smoothing capacitor. The first auxiliary switching means becomes an on state during a normal operation, whereas the first auxiliary switching means goes into an off state in a case where the detection means detects that the leak current of the input smoothing capacitor becomes a predetermined value or more.

Abstract: A circuit that provides a method and apparatus to actively balance capacitor leakage current from series stacked capacitors and disconnects itself when stacked capacitors are configured for doubler operation. In one embodiment, the active circuit includes high voltage low current transistors, such as for example a PNP bipolar transistor and an NPN bipolar transistor, that are configured in a sink-source voltage follower arrangement with the bases of the transistors connected to a voltage divider network and referenced to a fraction of a DC input voltage with a very high impedance, low dissipative resistor divider network. In one embodiment, the emitters of the PNP and NPN transistors are both tied to the connection point between capacitors in the stack and provide an active sink-source drive, which maintains the voltage at this point to be bounded by the input reference voltages of sink-source followers.

Abstract: An inrush current control circuit includes a first and second control units connected in series, wherein the first and second control units all have a current limiting resistor and switch connected in parallel. The current limiting resistor of the first control unit is used to prevent an inrush current generated at the moment an alternative current is supplied. The switch of the first control unit turns on based on the voltage of the capacitor, and current bypasses the first current limiting resistor. The current limiting resistor of the second control unit is used to prevent an inrush current generated at the moment an alternative current shifts from a high voltage level to a low voltage level or from a low voltage level to a high voltage level. The switch of the second control unit turns on based on the alternative current and current bypasses the second current limiting resistor.

Abstract: There is described a method for controlling a quenching device for a converter bridge with line regeneration, whereby the converter bridge controlled by a network-timed control circuit by ignition pulses is connected with its three inputs to the phases of a three-phase network and the two outputs of the bridge are connected to a direct-current motor which feeds, when operated as a generator, current back to the three-phase network via the bridge. The quenching device is controlled by a trigger unit which emits trigger pulses depending on the monitoring of electrical and temporary variables. The quenching device comprises, for each bridge half, a quenching condenser that can be charged by a charging circuit quenching voltage. The quenching condensers, in the event of quenching, can be connected to the bridge halves by means of switches that are controlled by the trigger unit.

Abstract: A method and apparatus for altering converter control as a function of the degree of unbalance in supply line voltages to substantially eliminate second harmonics on the supply lines caused by active control of the converter including identifying supply line peak amplitude values and using the peak values to identify potential second harmonics and then altering command values as a function of the potential second harmonic components.

Abstract: A circuit (20) for powering a load (50) includes a rectifier circuit (200), a voltage clamping circuit (300), and a DC-to-DC converter (400) such as a buck-boost converter. Voltage clamping circuit (300) is coupled between the rectifier circuit (200) and the DC-to-DC converter (400), and functions to prevent the input voltage (VIN) of the DC-to-DC converter (400) from exceeding a predetermined acceptable level, so as to protect the DC-to-DC converter (400) from damage due to transients in a voltage (VAC) provided by an AC line source (40). Preferably, voltage clamping circuit (300) is realized by an arrangement that includes a voltage divider circuit (320), a voltage sensing circuit (340), and an energy-limiting circuit (360), and is well-suited for use in power supplies and in electronic ballasts for powering gas discharge lamps.

Abstract: A rectifier includes a switching circuit and a controller. The switching circuit is coupled between positive and negative buses and a plurality of input voltage sources. The switching circuit includes a plurality of pairs of switching devices. Each pair is associated with one of the input voltage sources. The controller includes first and second control loops operable to generate control signals for operating the pairs of switching devices to generate a potential across the positive and negative buses. The controller is further operable to estimate a line inductance seen by the rectifier based on at least one of the control signals and generate an inductance compensation gain factor for applying to the control loops based on the estimated line inductance.

Abstract: An output voltage circuit for power supply aims to arrange output DC power according to component voltage and equalizing current. The power supply has a voltage transformation circuit which consists of transformers each has at least one high voltage power and one low voltage power. The high voltage power output from each transformer is coupled in parallel and integrated on the same line to be output to a load at the rear end. Each low voltage power is output through a single line to another load at the rear end. Thus the load of the transformers is reduced and a desired electricity condition can be maintained.

Abstract: A method and apparatus for converting AC power into DC power are disclosed, where the method includes receiving the AC power, and converting the AC power into the DC power by way of a rectification device, where the rectification device is capable of being controlled to switch on at a plurality of time instants. The method further includes experiencing at least one of a first reduction in a first characteristic of the received AC power and a second reduction in a second characteristic of the DC power; and changing at least one of the time instants at which the rectification device is to be switched on.

Abstract: A power supply device (1) converting received power signals to direct current signals to ensure a load to work normally. The power supply device includes a transformer circuit (10), a rectifier circuit (11), and an inrush current control circuit (12). The transformer circuit converts the received power signals to alternating current signals. The rectifier circuit is connected to the transformer circuit, and converts the alternating current signals to direct current signals. The inrush current control circuit is connected to the rectifier circuit, for limiting inrush current from the power supply device. The inrush current control circuit includes a voltage divider resistor (R1) and a filter capacitor (C1). The filter capacitor is connected to the voltage divider resistor in series. In the invention, the power supply device uses the inrush current control circuit to limit the inrush current, thus life of the components is lengthened, and the power supply device is stable.

Abstract: A PWM motor speed control circuit (10) includes a PWM signal generator (20), a driver integrated circuit (IC) (101) and a photocoupler (30) coupled between the PWM signal generator and the driver IC. The photocoupler receives an original PWM signal generated by the PWM signal generator and outputs a new PWM signal in response to the original PWM signal, wherein a voltage parameter of the original PWM signal is isolated by the photocoupler from a voltage parameter of the new PWM signal. The new PWM signal is fed to the driver IC and used for controlling speed of a motor (100).

Abstract: A start signal output circuit having an RF/DC conversion circuit to which radio frequency power (RF) of specified frequency is inputted and from which a direct current potential (DC) is outputted, comprises a detection/amplification circuit 210 which includes a voltage doubler wave-detector circuit 10 configured including a sensing diode Q1 (Tr34) for sensing the RF power, a differential amplifier including differential pair transistors Tr31 and Tr32, and a current mirror circuit. A base current of one Tr31 of the differential pair transistors is brought into substantial agreement with a DC component of a current flowing through the sensing diode Q1 (Tr34). A total of currents flowing through the differential pair transistors Tr31 and Tr32 is regulated to a substantially constant value by the current mirror circuit. Thus, the start signal output circuit which is small in size, high in sensitivity and low in power consumption can be realized.

Abstract: An improved capacitive drop power supply is provided for use in home appliances. The power supply circuit includes: a rectifier for converting an AC power source to a DC voltage; a current limiting capacitance interposed between the AC power source and the rectifier; a low voltage output stage and a higher voltage output stage. The low voltage output stage supplies DC voltage from the rectifier to a microcontroller residing in the home appliance. The higher voltage output stage is connected in series with the low voltage stage and supplies DC voltage to the higher voltage loads associated with the home appliance. To reduce power consumption, a shunt circuit path is connected in parallel across the higher voltage output stage which causes a phase shift in the AC power signal and thereby reduce real power consumption when a no load condition is placed on the output stage (e.g., during a standby operating condition of the home appliance).

Abstract: An energy-feedback clamping circuit of a power converter is proposed. The converter includes a transformer coupled to a full-wave rectifier circuit. The clamping circuit includes: two clamping diodes having two anodes coupled to each other at a common-anode terminal and two cathodes coupled to two terminals of a secondary winding of the transformer, a first clamping capacitor having a first terminal coupled to a cathode of a first rectifying diode of the rectifier circuit and a second terminal coupled to the common-anode terminal, a second clamping capacitor having a first terminal coupled to a connecting node of the output filtering inductor and capacitor of the rectifier circuit and a second terminal coupled to the common-anode terminal, and a converter circuit having an input terminal coupled to the second clamping capacitor and an output terminal for offering a power source.

Abstract: A switching power supply with clamping circuit includes a clamping circuit between a slave output terminal and a master output terminal thereof, to prevent voltage drift at the slave output terminal. The clamping circuit includes a switching circuit connected between the slave output terminal and the master output terminal, and a voltage stabilizing circuit connected between the slave output terminal and the switching circuit. When the output voltage at the slave output terminal steps up to a certain level, the voltage stabilizing circuit functions and enables the switching circuit, and therefore prevents the output voltage from climbing higher than the load requires.

Abstract: A circuit that provides a method and apparatus to actively balance capacitor leakage current from series stacked capacitors and disconnects itself when stacked capacitors are configured for doubler operation. In one embodiment, the active circuit includes high voltage low current transistors, such as for example a PNP bipolar transistor and an NPN bipolar transistor, that are configured in a sink-source voltage follower arrangement with the bases of the transistors connected to a voltage divider network and referenced to a fraction of a DC input voltage with a very high impedance, low dissipative resistor divider network. In one embodiment, the emitters of the PNP and NPN transistors are both tied to the connection point between capacitors in the stack and provide an active sink-source drive, which maintains the voltage at this point to be bounded by the input reference voltages of sink-source followers.

Abstract: Filter network for the reduction of the voltage switching speed between an electrical motor drive and an electrical motor and/or between an electrical distribution network and a motor drive, comprising for each electrical phase a self-damped inductor having a complex impedance determined by a magnitude (Z) and a phase (?), the phase (?) of the complex impedance being comprised between 80 and 90 degrees in the frequency range of the motor's current, and being less than 60 degrees in the frequency range of the overvoltage oscillations. Using the inventive filter network, it is possible to manufacture low cost and small size du/dt-filters generating low voltage overshoot and low losses.

Abstract: A DC-DC converter comprises an input circuit that stores inductive energy that includes a first switch that releases the stored inductive energy. A transformer includes a primary winding that communicates with the input circuit and a secondary winding. An output circuit communicates with the secondary winding and that includes first and second output conductors and a first diode that communicates with one end of the secondary winding and the first output conductor. A second diode communicates with one end of the secondary winding and the second output conductor. A third diode communicates with an opposite end of the secondary winding and the first output conductor. A fourth diode communicates with an opposite end of the secondary winding and the second output conductor. A first capacitor is connected in parallel to the third diode. A second capacitor is connected in parallel to the fourth diode.

Abstract: In a rectifying circuit, a rectifying diode is configured to rectify a first AC voltage to output a first DC voltage. A protection diode circuit has constant reverse voltage diodes and electrically connected to the rectifying diode in parallel thereto. The constant reverse voltage diodes are electrically connected to each other in series. Each of the constant reverse voltage diodes has a breakdown voltage and a second forward voltage. A sum of the breakdown voltages of the constant reverse voltage diodes is lower than the breakdown voltage of the rectifying diode, and a sum of said second forward voltages is higher than the first forward voltage of the rectifying diode.

Abstract: A drive controller for a self-commutated converter is described. The converter has two half-bridges, and the drive controller includes a corresponding control circuit for the converter valves of each half-bridge. Each control circuit can be connected via first switches to an external voltage. Each first switch is connected in parallel with a second switch, wherein the second switches are decoupled by way of decoupling diodes. The first and second switches can be alternatingly switched on and off. The switches can therefore be cyclically tested without interrupting service.

Abstract: A circuit that provides a method and apparatus to actively balance capacitor leakage current from series stacked capacitors and disconnects itself when stacked capacitors are configured for doubler operation. In one embodiment, the active circuit includes high voltage low current transistors, such as for example a PNP bipolar transistor and an NPN bipolar transistor, that are configured in a sink-source voltage follower arrangement with the bases of the transistors connected to a voltage divider network and referenced to a fraction of a DC input voltage with a very high impedance, low dissipative resistor divider network. In one embodiment, the emitters of the PNP and NPN transistors are both tied to the connection point between capacitors in the stack and provide an active sink-source drive, which maintains the voltage at this point to be bounded by the input reference voltages of sink-source followers.

Abstract: In a boost converter, an energy recycle circuit can be normally operated only when the output voltage is larger than the input voltage. In certain cases, such as when the output is in the abnormal operation, the output voltage could be equal to or less than the input voltage so that the current on the inductor of the energy recycle circuit would be increased to damage the switch element of the energy recycle circuit, and then the rectifying diodes of the boost converter would be damaged too. The present invention relates to a simple auxiliary circuit including a controllable voltage source for resetting the inductor of the energy recycle circuit under the abnormal operation so as to protect the boost converter and to improve the safety of the power supply.

Abstract: In a rectifying circuit, a rectifying diode is configured to rectify a first AC voltage to output a first DC voltage. A protection diode circuit has constant reverse voltage diodes and electrically connected to the rectifying diode in parallel thereto. The constant reverse voltage diodes are electrically connected to each other in series. Each of the constant reverse voltage diodes has a breakdown voltage and a second forward voltage. A sum of the breakdown voltages of the constant reverse voltage diodes is lower than the breakdown voltage of the rectifying diode, and a sum of said second forward voltages is higher than the first forward voltage of the rectifying diode.

Abstract: A rectifier of a power supply comprises a delay unit at a front end of a circuit for delaying a transient variation of a power current and then delaying the current to a rectifying end; a driving unit coupling to the delay unit by two inductors for adding an inducting voltage to a voltage of a switch unit at an input end for being converting as a driving voltage and for emitting a state of the driving unit based on a waveform of the driving voltage; and the switch unit being connected to the driving unit for receiving the state of the driving unit and for conducting or cutting-of the power current so that the operation of the switch unit is synchronous with the waveform of the power current.

Abstract: A circuit that provides a method and apparatus to actively balance capacitor leakage current from series stacked capacitors and disconnects itself when stacked capacitors are configured for doubler operation. In one embodiment, the active circuit includes high voltage low current transistors, such as for example a PNP bipolar transistor and an NPN bipolar transistor, that are configured in a sink-source voltage follower arrangement with the bases of the transistors connected to a voltage divider network and referenced to a fraction of a DC input voltage with a very high impedance, low dissipative resistor divider network. In one embodiment, the emitters of the PNP and NPN transistors are both tied to the connection point between capacitors in the stack and provide an active sink-source drive, which maintains the voltage at this point to be bounded by the input reference voltages of sink-source followers.

Abstract: A power supply including an inverter receiving a DC input signal from a DC input source (11). The inverter is comprised of two half bridges (S1A, S2A and S1B, S2B). Each inverter is driven by a signal source (13A, 13B), which outputs an AC signal. The output from each inverter is input to a first stage harmonic filter. The power supply includes an output circuit that includes first and second rectifiers (D1, D2) arranged about a point so that if the inverter attempts to drive the point beyond a predetermined first and second voltage, the respective rectifier conducts in order to return at least one of power and current to the DC input source. The output from the first harmonic filter (L1A, C1; L1B, C1) is output to a second harmonic filter (L2, C2) and is then output from the power supply.

Abstract: A noise canceling circuit that eliminates noise from an AC current of an AC power supply is provided with a changeover device that brings the noise canceling circuit into and out of conduction with a secondary side of a transformer in accordance with an on-off state of a switch. The noise canceling circuit includes a filter portion. The changeover device may be a relay or triac.

Abstract: A switching power supply comprises a transformer 3, a switching circuit 1, an output rectifier circuit, an output smoothing circuit, and a snubber circuit. A snubber capacitor 17 has one terminal connected to the one terminal of a snubber diode 19. The other end of the snubber capacitor is led to an output winding 4 of the transformer, while the other terminal of the snubber diode is led to the other of the electrode of an output rectifier diode 7. A snubber inductor 23 has one end connected to the connecting point of the snubber capacitor and the snubber diode, and the other end is. connected to the input side of the output smoothing circuit. The polarity of the diode is arranged to establish a charging loop circulating through the snubber diode, the snubber capacitor and the output winding of the transformer, so as to provide a reduced loss, in a cycle in which the voltage appearing at the output winding of the transformer is the reverse direction to the output rectifier diode.

Abstract: An A.C./D.C. converter including a filtering capacitor and further including a first branch essentially including a first rectifying circuit and a current limiting circuit; a second branch essentially including a second rectifying circuit, the series voltage drop of which is limited to that of the switches forming it; and a selection circuit for selecting one of the two rectifying circuits.

Abstract: A circuit including bridge rectifier, switches across one or more of the diodes of the bridge rectifier, and a comparator providing control signals to the switch or switches can be constructed to apply a constant polarity voltage to an electrical load, regardless of the polarity of the input power applied to the circuit. The comparator produces a control signal depending upon a comparison of the input power voltages, and the control signal activates one or more of the switches to allow current flow through an appropriate path in the circuit to yield the constant polarity across the electrical load. Thus, the circuit can protect the electrical load from an inappropriately applied voltage by switching the applied voltage's polarity. Because an activated switch can short a diode in the bridge rectifier, power loss associated with current flow through the diode is reduced. Additionally, the circuit can provide constant polarity across the electrical load with either AC or DC input power.

Abstract: A safer power supply is used in conjunction with a system for preserving food, oil, organs, or other organic material. The power supply constantly applies a high voltage-weak pulse electric voltage, generated by a transformer using an alternating-current power supply of commercial frequency, with the voltage applied through an electrically conducting electrode to the food or other organic materials. In the power supply, one pole of the secondary winding is sealed for increased safety. By applying or impressing high voltage-weak pulse electric current to frying oil or other organic materials using the power supply and/or the preservation system, the high voltages restrain deterioration of frying oil and enables long-term use. Installed on a food container which is placed in a refrigerator, the power supply safely applies high voltage-weak pulse electric current to meat and fish in the container, and so suppresses propagation of germs and deterioration.

Abstract: A DC power supply apparatus includes a rectifier circuit which rectifies an input commercial AC voltage. The rectifier output voltage is smoothed in a smoothing capacitor. The DC voltage from the capacitor is converted to a high-frequency voltage in an inverter. The high-frequency voltage from the inverter is voltage-transformed by a transformer into a voltage-transformed, high-frequency voltage, which is then converted back into a DC voltage in a high-frequency-to-DC converter circuit. When an input commercial AC voltage is applied to the DC power supply apparatus, a pre-charging circuit pre-charges the smoothing capacitor from the input AC voltage. If a voltage having a magnitude larger than a prescribed value is applied to the DC power supply apparatus, an overvoltage protection circuit renders the rectifier circuit and the pre-charging circuit inoperative.

Abstract: A high frequency alternating current (AC) voltage regulator module (VRM) includes a protection circuit that regulates a level of current from power in a high frequency AC domain received from an AC bus. A post-regulator unit is coupled to the protection circuit. The post-regulator unit regulates the power to a component on a computer system.

Abstract: An integrated power factor converter utilizes a silicon controlled rectifier (SCR) bridge which limits the inrush current by controlling the conduction angle of the SCR's. The same SCR bridge shuts down the output in case of short circuit and recovers automatically at a predetermined duty cycle rate. In case the input voltage exceeds approximately 275 VAC, the SCR bridge regulates the output voltage to below 400 VDC. The input inrush current is reduced by phasing up the input voltage in a controlled manner. The use of SCR's in the input bridge produces no additional losses, since the rectifier function is required regardless of which topology is used. The integrated power factor converter interfaces universal voltage mains to DC/DC converters while reducing input harmonics.

Abstract: A controlled rectifier or SCR bridge converts a plurality of alternating current voltages from a plurality of alternating current phases to a rectified voltage. The bridge includes an input interconnected with the alternating current phases and an output having the rectified voltage. The bridge has a segment for each of the positive and negative polarities of the alternating current phases. Each of the segments has an SCR responsive to a control signal in order to control current conduction within the segment between the input and the output of the bridge. A phase control circuit outputs some of the control signals to some of the segments in order to control current conduction within the segments. A phase lock loop or startup circuit detects an abnormal condition of the AC voltages of the alternating current phases.

Abstract: A control method and apparatus for reducing transformer core volume in a power converter of the type having a switching circuit coupled to a primary winding of the transformer for selectively coupling the primary winding to a dc voltage source, a secondary winding of the transformer being coupled to an output rectifier circuit for developing a relatively high dc voltage across an output capacitor. The apparatus includes a high voltage zener diode clamp for limiting the maximum voltage on the capacitor, and the rectifier circuit includes at least a pair of zener diodes connected for blocking reverse current flow through the rectifier circuit.

Abstract: A power system recovery design which protects the integrity of an electronic controller system by inhibiting application of DC electric power to heavy load equipment until a user determines that application of DC electric power should be reinitiated. Once heavy load equipment has been placed in an inoperative state, the power system recovery design will maintain the inoperative state until an operator actively reinitiates the operative state.

Abstract: For use with a post regulator for a power converter, the post regulator having a rectifier circuit and an output circuit, an energy recovery snubber, a method of operating the same and a power converter employing the snubber or the method. In one embodiment, the snubber includes: (1) a clamping diode and a clamping capacitor, series-coupled between the rectifier circuit and the output circuit, that cooperate to recover reverse recovery energy developed in the power converter to an output thereof and (2) a charge balancing circuit, coupled to the clamping capacitor, that maintains a charge balance of the clamping capacitor.

Abstract: In a direct-current power supply system, an alternating current outputted from an AC power supply is converted by a second diode bridge circuit into a direct current. The direct current is smoothed by voltage doubler capacitors and a smoothing capacitor. A reactor is inserted into an input side of the second diode bridge in series. Detecting circuit is operatively connected to the AC power supply for detecting a zero-crossing point. When the zero-crossing point is detected by the detecting circuit, control means is adapted to firstly switch a switching element on for a first predetermined period of time and, after a predetermined delay period of time has passed since the switching element is firstly switched on, adapted to secondly switch the switching element on for a second predetermined period of time.

Abstract: For use with a power converter having a switching circuit coupled to a primary winding of a transformer and a rectifier coupled to a secondary winding of the transformer, the switching circuit exhibiting switching losses and the rectifier inducing reverse recovery currents in the converter, a snubber circuit and a method of reducing the switching losses and reverse recovery currents.

Abstract: A three-phase rectifier circuit for a capacitive load wherein only small current harmonics occur has, at the rectifier input, an inductance and a capacitor arrangement that compensates the reactive power of the inductance. The capacitors can be individually switchable, for the regulation of the rectifier output voltage.