Abstract: A method controls a power factor correction converter that includes a boost inductor and a switch. The method generates a sense signal representing a rectified AC input voltage or an inductor current through the boost inductor, turns on the switch in response to determining, based on the sense signal, a zero current condition through the boost inductor, turns off the switch after an on-time interval, generates a feedback signal based on an output voltage of the converter, and compares the feedback signal with a threshold. If the feedback signal is smaller than the threshold, the method generates a command signal, representing a phase domain including 0 and ?, based on the feedback signal and the power threshold, and keeps the switch off when a phase of the input rectified AC voltage or of the inductor current is in the phase domain even if the zero current condition has been determined.

Abstract: A power factor correction circuit may include a boost converter circuit in which a plurality of boost circuits including a boost inductor, a rectifying diode, and a boost switch are connected with each other; and a snubber circuit including a snubber inductor and a snubber switch so as to snubber the boost converter circuit. The snubber inductor may be controlled so as to be turned on before the boost inductor is turned on to apply zero voltage to the boost inductor. It is possible to reduce switching loss occurring when the boost switch is turned on and increase efficiency of an AC-DC power supply apparatus.

Abstract: A rectifier transformer including at least one secondary with windings, one pair of magnetic transductors per winding, one of the transductors having one or more first busbars and the other having one or more second busbars. All of the busbars of the pair of transductors are connected to the same winding. The or each first or second, busbar is connected to a single positive or negative, terminal (2w+) designed to be connected to a positive or negative, arm of the rectifier. All of the busbars of the pair of magnetic transductors form one or more groups that are encircled by at least one magnetic toroid and that comprise at least one first busbar and at least one second busbar, so that, when the terminals are short-circuited, the busbars of a group pass currents of opposite directions such that the sum of the currents in one direction is equal to the sum of the currents in the other direction.

Abstract: A power conversion apparatus determines a peak value of circuit current in each pulse cycle and a lower limit value lower than the peak value, from a corrected output voltage value obtained by subtracting a predetermined reference voltage from an output voltage detected, and an input voltage detected. The pulse signal output unit outputs a pulse signal to the first switch when the polarity of input voltage is positive, and outputs a pulse signal to the second switch when the polarity of input voltage is negative. A pulse signal is turned on in response to start of a pulse cycle, and is kept on until a circuit current detected reaches a peak value. A pulse signal turns off when a circuit current reaches a peak value, and turns on again when a circuit current decreases to a lower limit value.

Abstract: A control method is used in a power factor corrector. Firstly, a current command signal from a computing circuit is received. Then, the current command signal is compared with an input signal of the power conversion circuit, so that a current error signal is generated. If the power factor corrector is operated in a transition interval between the first mode and the second mode, an addition operation is performed on the unadjusted current error signal, a feedforward signal and the adjusted current error signal, thereby generating a current control signal. A switch control signal is generated according to the current control signal. A switching element of a power conversion circuit is controlled according to the switch control signal. Consequently, the harmonic distortion of the input current is inhibited.

Abstract: The present invention is directed to an electrical supply apparatus having an input for connecting the electrical supply apparatus to a mains supply which provides an alternating voltage as input voltage, having an output for connecting the electrical supply apparatus to a load, wherein the output provides a DC voltage as output voltage, having a rectifier which rectifies the input voltage to form a rectified input voltage, having a PFC module which comprises a smoothing device for smoothing the rectified input voltage and an active power factor correction device, wherein the power factor correction device is designed to form a time-dependent supply current for the smoothing device depending on a time-dependent current form signal in such a way that a time-dependent input current in the PFC module is matched to the current form signal, wherein the current form signal is produced by an analogue circuit.

Abstract: A linear transformer power supply is disclosed that extracts a high level of energy from a linear transformer during the full cycle of AC input voltage.

Abstract: An aircraft power supply for providing DC power with improved power quality characteristics. The aircraft power supply includes a transformer control system that can use closed-loop feedback from a DC power output to control switches that can short primary windings turns of a step-down transformer. By shorting turns in the primary, the transformer control system can control or manipulate the turns ratio in the transformer and compensate for decreases in the DC power output.

Abstract: Energy management of an electronic device using multiple electric power sources. The electric power sources may include a parasitic electric power source, a rechargeable electric power source, an intermittent electric power source, and a continuous electric power source. The electronic device further may include a power supply for receiving the electric power from the source(s) and supplying electric power to the various components of the electronic device that require power. The electronic device may include a source selector for controlling which power source supplies electric power to the power supply. Energy management of the electronic device may be configured to use a permanently exhaustible power source such as a battery only when other power sources are unavailable.

Abstract: A power converting device is disclosed that can reduce switching loss occurring in a voltage source inverter that drives an AC motor. It is possible to supply DC power to the voltage source inverter from both a voltage source rectifier, which converts AC power from an AC generator into DC power, and a battery. A first switching circuit is inserted between the voltage source rectifier and the AC generator, and the battery is connected to the output side of the voltage source rectifier. A second switching circuit is inserted between the battery and the voltage source inverter. A third switching circuit and a reactor are inserted in series between the input side of the voltage source inverter and the input side of the voltage source rectifier. At least one of an upper arm and a lower arm of the voltage source rectifier can be chopper controlled.

Abstract: To reduce gate-drive losses caused by high switching frequency operation, embodiments herein include a novel resonant gate driver circuit for driving switches. This gate drive circuit can include a simple two-half-bridge structure. A coupling inductor of the resonant gate driver circuit can provide energy circulation between gates of high and low side switches and also works as a voltage-boost transformer. According to one configuration, the resonant gate driver circuit can be extended to drive two MOSFETs with a common ground. Both theoretical and simulation results for the new resonant gate driver circuit illustrate increased efficiency via lower switching losses.

Abstract: The present invention is related to a switched-mode power supply. It is also related to a LED lighting system and driver which comprise such a switched-mode power supply. In addition, the present invention is related to a method for electrically driving a load. According to the present invention, the switched-mode power supply is switched from a charging state, in which an energy storage is charged, to a discharging state, in which the energy storage feeds a load, when a current limit has been exceeded. This current limit is set proportional to an instantaneous voltage outputted by the rectifier.

Abstract: According to one embodiment, a power conversion apparatus determines a peak value of circuit current in each pulse cycle, from a corrected output voltage value by subtracting a predetermined reference voltage from an output voltage detected by the output voltage detector, and an input voltage detected by the input voltage detector. The pulse signal output unit outputs a pulse signal to the first switch when the polarity of input voltage is positive, and outputs a pulse signal to the second switch when the polarity of input voltage is negative. A pulse signal turns on in synchronization with a clock signal input from the oscillator, and is kept on until the circuit current detected by the circuit current detector reaches the peak value. A pulse signal turns off when the circuit current reaches the peak value, and turns on again in synchronization with the next clock signal.

Abstract: A two-phase critical interleave PFC boost converter, includes a master-side control circuit configured to critically control a first switching element based on a master signal; and a slave-side control circuit configured to critically control a second switching element based on a slave-signal with a phase difference of 180° from the master signal. In the PFC boost converter, an off period generator of the master-side control circuit feeds an M_ON signal which is the same in waveform as the master signal to an on phase controller of the slave-side control circuit, and the slave-side control circuit determines the rising timing of the slave signal from the rising time of the master signal.

Abstract: A power converter stabilizes a voltage by controlling leading of an AC current and performs maximum charging within contracted power reception amount when connected to a weak power system. The power converter comprises Magnetic Energy Recovery Switch comprising a bridge circuit including at least two reverse conductive type semiconductor switches and a magnetic energy accumulating capacitor with a small capacity connected between DC terminals of the bridge circuit. The power converter uses the Magnetic Energy Recovery Switch to perform power conversion from AC to DC or vise versa. Plurality of secondary battery charging devices each comprising the power converter have a DC part connected to a common DC bus bar, so that power is accommodated among the secondary battery charging devices.

Abstract: Power line current fed power supplies producing stable load currents and related methods are described. The power supplies may include a current transformer coupled to an inductive network. In some embodiments, the current transformer operates in saturation mode. In some embodiments, a substantially constant DC current is generated having a magnitude that remains substantially constant despite variations of the magnitude of AC current in the power line.

Abstract: A power factor correction converter includes a diode bridge that rectifies an alternating-current voltage input from an alternating-current input power supply Vac, a series circuit including an inductor and a switching element, a rectifying smoothing circuit connected in parallel with the switching element and including a diode and a smoothing capacitor, and a digital signal processing circuit that controls turning on and off of the switching element such that the input current input from the alternating-current input power supply Vac comes to have a similar shape to the alternating-current voltage. The current flowing through the inductor in the off period of the switching element is detected by using a current detection resistor, the operation mode is determined on the basis of the inductor current IL at a predetermined timing and the switching element is optimally controlled in accordance with the operation mode.

Abstract: A control method implemented in a power converter, such as a variable speed drive, is disclosed. This control method is designed to make the power converter operate when the latter is connected to the network in single-phase mode. The power converter includes a controlled current source connected in series to its DC power supply bus. This controlled current source includes an electronic converter provided with two controlled switching arms. The switching arms are controlled by alternating a modulation phase with a saturation phase, the saturation phase being applied for a determined duration ? in order to make the power converter operate in discontinuous mode.

Abstract: An increase in a ripple voltage of a capacitor in a smoothing circuit is prevented to achieve a compact capacitor and cost reduction for capacitors in an electric power supply circuit which performs PAM control using a switching element. An electric power supply circuit includes a bridge circuit for rectifying alternating current power, a smoothing circuit which has two capacitors serially connected to each other, and a PAM control section for turning a switching element on and off at a predetermined timing. The PAM control section includes a phase difference detection section which detects a phase shift of a PAM waveform based on a change in a voltage difference between the two capacitors, and a phase correction section which corrects the phase of the PAM waveform so that an input current has a sine waveform.

Abstract: A power supply unit includes multiple input terminals to which alternating-current power is input; a positive terminal and a negative terminal for outputting direct-current power; a rectifier circuit configured to rectify the input alternating-current power; a first inductor connected to the rectifier circuit; a first capacitor connected between the positive terminal and the negative terminal; a first rectifying device connected between the output terminal of the first inductor and the positive terminal and having a rectification direction in a direction from the output terminal of the first inductor toward the positive terminal; a switching device connected between an input terminal of the first rectifying device and the negative terminal; a second rectifying device and a second capacitor connected in parallel to the switching device; and a second inductor connected between a connection of the second rectifying device and the second capacitor and the positive terminal.

Abstract: One embodiment of an improved energy conversion and storage system uses pre-charge-enabled energy-converting variable capacitors that can be substantially encapsulated in asphalt roads or streets. Another embodiment can be substantially encapsulated in concrete walls or rooftops. Radiant solar energy does work on temperature-sensitive capacitors. Temperature change, in one embodiment, modifies the capacitance of the previously pre-charged capacitor, thereby converting solar energy into increased electrical energy available for practical use, without needing parabolic reflectors and without needing any moving parts. Other embodiments are described and shown.

Abstract: A regulated power supply apparatus and method is provided. A converter circuit is configured to generate a regulated voltage signal from an unregulated voltage signal. A power sequencing circuit includes an unregulated voltage source input terminal and is configured for coupling an unregulated voltage signal to an unregulated voltage signal input terminal of the converter circuit. The power sequencing circuit includes an enable output coupled to the enable signal input terminal and includes a power limiting circuit and a trigger circuit. The power limiting circuit includes a first cascade of discrete analog components as controls for a first switching element and the trigger circuit includes a second cascade of discrete analog components as controls for a second switching element. The first cascade is configured as a charge control circuit for controlling a rate of charge of a first filter network and includes a zener diode coupled in parallel.

Abstract: Disclosed herein are various embodiments of compact coil power transformers configured to provide high voltage isolation and high voltage breakdown performance characteristics in small packages. Compact coil transformers are provided across which power may be transmitted and received by primary and secondary coils disposed on opposing sides of a substrate without high voltage breakdowns occurring therebetween. At least portions of the compact coil transformer are formed of an electrically insulating, non-metallic, non-semiconductor, low dielectric loss material. The compact coil transformers may be formed in small packages using, by way of example, printed circuit boards, flex circuits, lead frames, CMOS and other fabrication and packaging processes.

Abstract: A power factor correction circuit having an input current for reducing the distortion and harmonics generated in a power line feeding power supply. The power factor correction circuit includes a control switch (such as an IGBT) for producing a control switch current and virtual short circuit; a load for acting as power demand from a load and producing a load current; and one or more of resistors for measuring current within said circuit.

Abstract: Disclosed is a Power Factor Correction Controller, which comprises a boost converter, a current sensing unit, an arithmetic unit, and a switch driving unit. The current sensing unit can sense or derive the current that pass through the energy delivery device, which is normally implemented by a diode or a switch. The current sensing unit can also sense the inductor current, or the switch current. With the current sensing unit, the arithmetic unit can calculate the optimum switch on-time or when to turn off the switch, without direct-sensing of the load. The disclosed method reduces the system cost by removing the needs to sense the load condition as in the prior arts. The disclosed method also improves the system response by sensing the delivered current at energy delivery side, rather than the receiver side as in the prior arts.

Abstract: A buck converter LED driver circuit is provided. The driver circuit includes a buck power stage, a rectified AC voltage source, a voltage waveform sampler, and a control circuit. The buck power stage includes at least one LED and provides a first signal directly proportional to the current through the LED. The rectified AC voltage source is coupled to the buck power stage for driving the buck power stage. The voltage waveform sampler is coupled to the rectified AC voltage source for providing a second signal directly proportional to the voltage provided by the rectified AC voltage source. The control circuit is coupled to the voltage waveform sampler and the buck power stage for turning on and turning off the buck power stage according to a comparison between the first signal and the second signal.

Abstract: An active power factor correction (PFC) circuit and its controlling method are provided. The method comprises the following steps. Drive the power switch of the circuit so that the average inductor current waveform follows the rectified input voltage waveform. Suspend the operation of the power switch at a first moment in a first line cycle of the rectified input voltage and then resume the operation of the power switch at a second moment in a second line cycle of the rectified input voltage. The first moment is when the phase angle of the rectified input voltage exceeds a predetermined angle and the switching frequency of the power switch exceeds a predetermined frequency. The time span from the first moment to the end of the first line cycle is substantially as long as the time span from the beginning of the second line cycle to the second moment.

Abstract: The switched-mode power supply contains a transformer, a switching transistor in series with the primary winding of the transformer, and a damping network on the secondary side, which has a connection for a further secondary winding via which energy is transferred from this damping network, by way of example, to a charge-storage capacitor which is coupled to this secondary winding. The connection is advantageously produced via a rectifying element, for example a diode, which is coupled after the rectifying diode (D5) for the second secondary winding. In a further exemplary embodiment, the diode in the series circuit, which is connected in parallel with the rectifier diode for the first secondary winding, is not coupled to the charge-storage capacitor for the first secondary winding, but is likewise coupled to the charge-storage capacitor for the second secondary winding.

Abstract: A coupled-inductor current-doubler topology for a power converter has first and second rectifiers and first and second coupled inductors. Each coupled inductor has a main inductor inductively coupled with a secondary inductor. The secondary inductor of the first coupled inductor is coupled in series with one of the first and second rectifiers and the secondary inductor of the second coupled inductor coupled in series with the other one of the first and second rectifiers.

Abstract: A method of designing a high power factor integrated ferroresonant constant current source includes the steps of providing an input coil disposed about a ferromagnetic core and to be coupled to an AC voltage source. An output coil is to be coupled to a load. A control coil is coupled to a switch for regulating current output of the constant current source. A first capacitor coil is inductively coupled to the output coil and coupled to a capacitor to provide a first resonant sub-circuit having maximum gain, and a second capacitor coil is inductively coupled to the control coil and coupled to a capacitor to provide a second resonant sub-circuit to control resonant gain. A flux density (BPRI) is selected for a portion of the core around the input coils that is substantially lower than the flux density BCAP of a portion of the core around the capacitor coils.

Abstract: A power supply apparatus having an AC power supply, a transformer, a switching element and a control circuit for controlling an operation of the switching element: where an electrical current is supplied to the primary side of the transformer intermittently when a main unit of an electrical appliance to which the power supply apparatus is applied is in a standby mode so that unnecessary power consumption is reduced. Further, a capacitance is provided between the AC power supply and the control circuit instead of the conventional initializing resistance and the control circuit is driven using an electrical current going through a reactance component of the capacitor, so that the energy loss is not caused any more by the initializing resistance.

Abstract: A power supply unit for use in a measuring instrument at a plant. An output from a current transformer mounted on a power supply line is controlled so that the range of a primary current producing a stable output is increased. The invention includes a current transformer mounted on a cable for providing power to an electric motor, and a power supply unit. The power supply unit includes a rectifier circuit, a short circuit, a reverse current inhibit element, a condenser, a voltage watching circuit, and a constant voltage element. The voltage watching circuit outputs a command signal when the voltage of the condenser exceeds a first level and connects the short circuit 32.

Abstract: In an upconverter comprising a choke, a switching element and a diode, the switching element is controlled in such a way that the time interval during which the switching element is non-conducting is proportional to the time interval during which the diode is conducting. The upconverter has a high power factor for a wide range of the amplitude of the line voltage and a wide range of power taken at the output of the upconverter.

Abstract: In an upconverter comprising a choke, a switching element and a diode, the switching element is controlled in such a way that the time interval during which the switching element is non-conducting is proportional to the time interval during which the diode is conducting. The upconverter has a high power factor for a wide range of the amplitude of the line voltage and a wide range of power taken at the output of the upconverter.

Abstract: A secondary active clamp for a power converter, a method of actively clamping energy of the power converter and a power converter employing the clamp or the method. The power converter has a primary switching circuit coupled to a primary winding of an isolation transformer and a rectifier coupled to a secondary winding of the isolation transformer. In one embodiment, the clamp includes (1) an inductor coupled in series with a freewheeling diode of the rectifier and (2) a series-coupled capacitor and clamping switch coupled in parallel with the inductor. The series-coupled capacitor and clamping switch cooperate with the inductor to mitigate adverse effects of a reverse recovery phenomenon associated with the rectifier and to effect substantially zero voltage switching of a power switch of the primary switching circuit.

Abstract: For use in a power converter having an inverter coupled to an output rectifier, a post-regulator, a method of operating the same and a power converter incorporating the post-regulator or the method. In one embodiment: (1) a switching circuit, having at least one controllable switch and coupled an output of the power converter, that receives an output voltage from the power converter and produces a phase-shifted waveform therefrom and (2) a transformer, having a primary winding coupled to the switching circuit and a secondary winding coupled to the rectifier, that delivers the phase-shifted waveform to the rectifier to regulate the power converter, thereby allowing the inverter to be unregulated.

Abstract: Autoranging power supply apparatus may comprise a power output section having a plurality of pairs of output terminals, each of which has a maximum voltage and current rating. A switching network associated with the power output section connects and disconnects the plurality of pairs of output terminals to the external load. A control system connected to the switching network operates the switching network in response to changes in the impedance of the external load to connect and disconnect to the external load selected ones of the plurality of pairs of output terminals of the power output section to compensate for impedance variations in the external load and to prevent from being exceeded the maximum voltage and current ratings for each of the plurality of pairs of output terminals.

Abstract: Device designed to control a coil forming part of a solenoid valve, for example in a contactor type device.A switching power supply 14 includes a winding S1 powering a control circuit 15 and another winding S2 placed with a switch T2 at the coil terminals. Switch T2 is controlled by the control circuit to power the coil in the hold phase starting from the switching power supply. This reduces disturbances during the hold phase.

Abstract: The blocking time maintenance circuit is applied to a resonant-transition ZVS power converter having saturable core reactors to induce a current in the primary of the transformer which enables ZVS. The circuit includes a peak detector for producing a signal having a magnitude proportional to an input voltage. A biasing mechanism, comprising a current source, is provided in order reset the saturable core reactors in a controlled manner. A control mechanism is connected to the peak detector and the current source in order to generate a reset current, the magnitude of which is correlated to the input voltage. In this manner, the volt-time product of the saturable reactors is varied, thereby maintaining the blocking time relatively constant over a wide range of input voltages and ensuring that the output voltage does not fall out of regulation.

Abstract: This invention provides cost-effective suppressing conducted radio-noise emissions from industrial inverter-motor drives whose EMI performance is able to meet the CISPR or FCC limits on conducted emissions. The invention includes some small size L,C filtering elements built inside the inverter, e.g., two grounding capacitance connected from both side of DC link to grounding heat sink of devices, a line capacitance across a DC link, three line capacitances across phase leads in AC input side of the diode rectifier, a zero sequence inductance both in each phase input and in each phase output lead of the inverter. Optionally, an extra secondary winding of the zero sequence inductor is connected to main circuit of inverter via a L, R, C network.

Abstract: High efficiency, post regulation of auxiliary outputs in multiple output-power supplies is provided by connecting a regulating switching device in parallel with a filter inductor connected in the current path from the rectifiers to the output terminal. For minimum output power for that auxiliary output, the switching device is held off at all times. When increased power is required, the switching device is turned on for a short period during each cycle of the inductor voltage. The switching system may be configured to conduct current from the output end of the inductor to the input end of the inductor or vice versa or either one selectively, in accordance with the particular regulation scheme chosen. Efficiency is maximized since current flows in the switching device for only a small portion of the cycle of the inductor voltage.

Abstract: A flyback type power supply has a nominal 12 volt secondary winding that is connected to a rectifier through the primary winding of a saturable transformer. The secondary winding of the saturable transformer is connected in series with the DC load current supplied by the rectifier. A filter capacitor completes the circuit. Under no load conditions, the impedance presented by the primary of the saturable transformer is high and the output voltage developed across the filter capacitor is maintained at about 12.25 volts. Under full load conditions, the impedance presented is negligible.

Abstract: A power supply (100) for producing a regulated output DC voltage from an AC voltage source (12) having at least one phase (14); a fullwave rectifier (16) coupled to the AC voltage source for producing a rectified output voltage potential, the fullwave rectifier having a number of pairs of diodes (D1-D6) equal to a number of phases of the AC voltage source; a number of pairs of magnetic amplifiers S1-S6 equal to a number of phases of the AC voltage source, each magnetic amplifier having a control input for varying an impedance between an input and an output in response to variation of a control signal; a control (36), responsive to the output voltage, for producing the control signal in response to the output voltage to cancel any variation in the output voltage from a regulated voltage; a fault detection circuit, responsive to an electrical load drawing current from the power supply for producing a shutdown signal; and a circuit, coupled to one of the magnetic amplifiers of each of the phases, responsive to t

Abstract: A circuit for regulating the output voltage of a switched mode power supply having a current mode magnetic amplifier includes a current transformer for sensing current flow through the magnetic amplifier. The sensed current is provided to a circuit which includes a resistor for developing a pulsating voltage and a storage capacitor for converting the pulsating voltage to a tracking voltage and storing the tracking voltage. The tracking voltage and a reference voltage are provided to a differential amplifier, the output of which operates a transistor which controls the operation of the magnetic amplifier, thereby regulating the output voltage of the power supply.

Abstract: A ringing choke converter power supply device comprising a ringing choke converter power supply for stabilizing an output voltage by an indirect feedback system; a variable impedance element provided on a primary or secondary side of the power supply; and a control circuit for transmitting a control signal to the variable impedance element in such a direction that an error signal obtained by comparing the output voltage of the power supply with a predetermined reference voltage becomes zero. The variable impedance element, which is preferably a saturable reactor, is interposed between a voltage detection winding and a feedback diode or between the feedback diode and a capacitor when the element is provided on the primary side; and is interposed between a transformer secondary winding and a rectifier circuit, when the element is provided on the secondary side.

Abstract: A power supply circuit comprising a transformer and rectifier diodes, where the ends of the secondary winding are connected to uniform first electrodes of a pair of rectifier diodes (D1, D2) whose second electrodes are connected to one output terminal (-) of the power supply circuit. According to the invention, also reactive components are provided, said reactive components being connected between the other output terminal (+) of the power supply circuit and the first electrode of respective ones of the rectifier diodes. When one reactance (e.g. L2) can send current (I.sub.L2) through one (D2) rectifier diode serving as an idler diode, while the secondary winding of the transformer draws current (I.sub.L1) through the same rectifier diode, a better utilization of the transformer is obtained than in the prior art, in particular when the output voltage is relatively low, while the output current is relatively high.

Abstract: A DC-DC converter having a transformer having a primary winding and a secondary winding; means for supplying DC input voltage to the primary winding; at least one switching element connected between the DC input voltage supplying means and the primary winding; rectifying means; at least one saturable reactor having a first winding and a second winding, the first winding being connected between one end of the secondary winding which is positive while the switching element is in a turn-on state and the rectifying means; and reset control circuit means connected to the second winding of the saturable reactor for supplying reset voltage thereto in response to output voltage of the rectifying means. The first and second windings have such polarities that the reset voltage can reset the saturable reactor during a turn-off period of the switching element. This DC-DC converter enjoys less temperature rise in the saturable reactor and a lower level of noise generation.

Abstract: A single phase, full wave diode bridge circuit is connected with a chopper on its DC output side. An output voltage of the chopper is smoothed by a smoothing capacitor and thereafter supplied for a load. A current control apparatus forms a current reference signal which is synchronized with an AC voltage applied to the bridge circuit and has a magnitude corresponding to a current flowing through the load and produces a deviation signal between the current reference signal and an actual AC input current of the bridge circuit. The chopper is controlled in accordance with the deviation signal so that the AC input current follows the current reference signal, whereby the power factor and the waveform of the AC input current in the bridge circuit are improved.

Abstract: An off-line switching power supply is described which controls the switching transistor of a fly-back circuit in such a fashion as to achieve better than 0.99 power factor control. The technique used for power factor control allows the switching power supply to operate either from AC or DC sources. The power supply operating from an AC source will accept all international voltages and line frequencies as input to produce a well-regulated DC output. The inductor of the fly-back circuit is maintained at the verge of continuous/discontinuous operation by the power factor control circuit to achieve a high efficiency operation and to minimize switching losses. The power factor correction circuit uses pulsewidth modulation and frequency modulation to control the switching transistor and maintain a high power factor under varying line and load conditions. The power supply also includes integral current limiting protection and RFI filtering for safe and quiet operation.

Abstract: A circuit is provided having an alternating current input and a synchronous switch means which has a control coil--such as a saturable reactor--with the input, so as to control the energy throughput of the synchronous switch means and therefore the output of the circuit. The current through the control coil is sensed and maintained in such a manner that the ampere-turns ratio of the control coil is maintained constant, thereby ensuring that the output of the circuit will be at a constant current irrespective of the internal resistance of the control coil or changes of that resistance. The output of the circuit may be an alternating current; more generally, it would be a direct current for such use as a battery forming and charging circuit.