Abstract: A controller for a multi-level converter regulates the DC midpoint voltage of the multi-level converter by accounting, for the effect non-redundant switch states have on the DC midpoint current. The controller includes a DC bus regulator that monitors the DC output voltage and generates in response a commanded voltage vector. The duty cycle calculator is operably connected to receive the commanded voltage vector generated by the DC-bus regulator and to generate in response to the commanded voltage vector duty cycles associated with non-redundant switch states. The DC midpoint regulator is operably connected to receive the non-redundant duty cycles calculated by the duty cycle calculator and to generate in response a first midpoint current command that accounts for the effect the non-redundant switch states have on the midpoint current.

Abstract: Provided is a contactless power receiving unit which has a simple configuration, and which is capable of generating constant induced electromotive force regardless of the orientation of a power receiving coil. Multiple power receiving coils are arranged to form certain relative angles to one another in a parallel magnetic field generated by a power supply unit. A rectifier circuit is connected to each power receiving coil. An adder circuit is configured to add DC power obtained, through the rectifier circuits, from the multiple power receiving coils, and to output resultant DC power of the addition.

Abstract: Power conversion systems and diagnostic techniques are presented for detecting suspected converter faults when a pre-charge circuit is engaged during system startup, in which known or estimated system characteristics are used to derive expected converter voltage values or rate of change values and the levels are measured during startup to ascertain whether the pre-charge circuit or other converter components are faulted.

Abstract: A battery-voltage detection circuit comprising: a first-capacitor; an operational-amplifier; a second-capacitor; a voltage-application-circuit to sequentially apply one and the other-battery-terminal-voltages to the other-first-capacitor-end; a discharge circuit to allow the second-capacitor to discharge before the other-battery-terminal-voltage is applied to the other-first-capacitor-end; a constant current circuit to output a constant-current causing predetermined-speed-discharge of electric charge accumulated in the second-capacitor in response to a discharge-start-signal input after voltage is applied to the other-first-capacitor-end; a comparator; and a measurement-circuit to measure a time-period from a time when the discharge-start-signal is input until a time when an comparator-output-signal changes to one logic level as a time-period corresponding to a battery-voltage, at least one of the operational-amplifier and the comparator being provided with an offset so that the comparator-output-signal chang

Abstract: A trigger signal generating device includes a first power source terminal and a second power source terminal; a first current generator to generate a first current with a first amplitude in accordance with the amplitude of the input signal; a second current generator to generate a second current with a second amplitude, the second current being flowed from the first power source terminal to the second power source terminal; a current mirror circuit to amplify the second current generated from the second current generator to obtain an amplified current; and a trigger signal generator to convert the amplified current into a trigger signal used for triggering a trigger device, the voltage amplitude of the trigger signal being corresponding to the current amplitude of the amplified current; wherein both of the first and second current generators are connected to either one of the first and second power source terminals.

Abstract: A front-end circuit of a power converter has a power connection wiring detecting circuit, a power switch and a control unit. The power connection wiring detecting circuit is connected to an AC power. The control unit is connected to the power connection wiring detecting circuit. The power switch is connected to the power loop. The control unit turns on or off the AC power loop through the power switch. When the power connection wiring is correctly connected with the AC power, the control unit turns on the power switch and the front-end circuit outputs the AC power to the back-end circuit. When the power connection wiring is incorrectly connected with the AC power, the control unit turns off the power switch and the AC power is not outputted to the back-end circuit.

Abstract: Charger for an industrial truck which has an asynchronous machine and a three-phase AC control unit for converting a battery voltage for the asynchronous machine, said charger having a mains power module which applies an AC voltage to one or two motor connection leads via a transformer, the charging current being rectified by half-bridges in the three-phase AC control unit.

Abstract: A power supply for powering one or more loads includes a boost circuit with power factor correction (PFC) that provides an operating voltage from an electrical power source, and a dimmer detection circuit that determines a dimming level applied to the electrical power source, and generates a pulse width modulated (PWM) signal based upon the dimming level. The power supply also includes one or more current control circuits, each current control circuit being associated with each of the one or more loads, and coupled in series with the operating voltage, its associated load, and a ground of the power supply, so as to control a current through its associated load in response to the PWM signal.

Abstract: A system and method for closed-loop efficiency modulation for an AC/DC power system is provided. A boost-buck converter and a DC/DC converter connected in series receive a rectified DC feed signal from a AC input signal and deliver a modified DC output to an active load. A controller receives power data at various stages of the system and uses that data to modify a series of trim voltages provided to the feedback inputs of the respective converters to modify each converters output voltage. The controller modifies each converter's output voltage to maximize power efficiency while monitoring other data in the system to ensure the system is operating correctly and safely.

Abstract: The present invention relates to voltage converters and especially to a control circuit with an input from the voltage converter output and arranged to control the voltage level on the voltage converter output. The problem addressed relates to the situation when there is a pre-bias voltage on the converter output at the moment it is switched on. The object of the control circuit is to increase the voltage on the converter output fast and avoiding any drain of voltage or current from the output at the start up sequence. This is performed by a comparator in the control circuit that is arranged to compare the reference voltage with a division of the output voltage and if the reference voltage is lower that the divided output voltage the reference voltage is increased at the comparator output. The comparator circuit includes an OP-amplifier.

Abstract: An uninterruptible power supply (“UPS”) has a phase-controlled rectifier coupled to a source of AC power and having an output providing a DC bus, the output of the phase-controlled rectifier coupled to an inverter. A first controller generates a firing angle for the rectifier and a fuzzy logic controller generates a firing angle for the rectifier. In an aspect, the rectifier is controlled by the firing angle generated by the first controller during normal operating conditions of the UPS and the rectifier is controlled by the firing angle generated by the fuzzy logic controller during abnormal operating conditions of the UPS. The abnormal operating conditions can include loss of a direct DC bus voltage measurement and or a period of time after the UPS experiences a large load change.

Abstract: A method and circuit is provided for reducing power consumption in a power transformer, typically incorporated into an electrical or electronic device such as a consumer device. In an embodiment, a detection/isolation circuit is coupled to an input of a power transformer/rectifier via a switching device. The switching device can be, for example, a solid state relay. The detection/isolation circuit is configured to sense the occurrence of no-load conditions in the power transformer and responsively disengage the power transformer from a coupled source of power (e.g., wall outlet) via the coupled switching device.

Abstract: A regulator with decreased leakage and low loss for a power amplifier is described. Switching circuitry is used to connect the regulator input bias to a bias control voltage when the power amplifier is to be operated in an on condition or to a voltage generator when the power amplifier is to be operated in an off condition.

Abstract: A single-stage integrated circuit drives LED sources in a constant power mode to eliminate the need for LED current sensing, while reshaping the waveform of the inductor current near line zero crossing to achieve high power factor. The integrated circuit achieves substantially constant input power my maintaining a constant voltage at a power factor corrector controller through an input voltage feedforward system. Accordingly, the disclosed circuit provides a high power factor, high efficiency, simple, and cost-effective solution with substantially consistent input power for both isolated and non-isolated offline LED applications.

Abstract: First and second rectification circuits are connected to a commercial AC power supply by a reactor. A load is connected between the output terminal on the positive side of the first rectification circuit and the output terminal on the negative side of the second rectification circuit. While the voltage or the commercial AC power supply remains at the positive level, a current flows through a path constituted by one of the diodes of the first rectification circuit and one of the diodes of the second rectification circuit. While the voltage of the commercial AC power supply remains at the negative level, too, a current flows through the path constituted by one of the diodes of the first rectification circuit and one of the diodes of the second rectification circuit.

Abstract: A rectifier circuit includes an input terminal that receives an alternating-current signal, a first rectifier circuit that generates a first direct-current voltage from the alternating-current signal, a bias-voltage generating circuit that generates a bias voltage from the first direct-current voltage, and a second rectifier circuit that generates a second direct-current voltage from the alternating-current signal biased with the bias voltage.

Abstract: A contact-input circuit for a power system device is described for processing a higher voltage signal from power system equipment or another power system device for use by a lower voltage circuit. The contact-input circuit generally includes a voltage threshold detection device adapted to allow current to flow therefrom when it detects that the higher voltage signal reaches a select threshold. An opto-isolator device, which is coupled to the voltage threshold detection device, provides a voltage signal suitable for use by the lower voltage circuit when the threshold detection device allows the current-flow through the opto-isolator.

Abstract: Various techniques directed to the digital control of a switching regulator are disclosed. In one aspect, a power supply regulator includes a compare circuit to be coupled to receive a feedback signal representative of an output level of a power supply. This causes a feedback state signal to be generated having a first feedback state that represents an output level of the power supply that is above a threshold level and a second feedback state that represents an output level of the power supply that is below the threshold level. An adjustment circuit is coupled to the compare circuit to adjust the feedback state signal in response to at least one of adjusting the threshold level or adjusting the feedback signal. The adjustment to the feedback state signal tends to cause the feedback state signal to revert from a state at the time of adjustment to a state immediately preceding the adjustment.

Abstract: The present invention discloses a secondary side switch-off timing adjusting method for a switching power conversion, comprising: detecting the falling edge of the voltage across a secondary side transistor according to a first reference voltage to generate a first reset signal; detecting the rising edge of the voltage across the secondary side transistor according to a second reference voltage to generate a first set signal; generating a secondary side discharging end signal from a latch operation in response to the first reset signal and the first set signal; and generating an off-predicting signal according to the cycle period of the secondary side discharging end signal. The present invention also provides a secondary side switch-off timing adjusting apparatus, and a system using the apparatus for a power conversion.

Abstract: The present invention relates to a pulse-width modulation (PWM) control device, especially to a PWM control device for use with a TRIode for an Alternating Current (TRIAC) dimmer. The PWM control device is comprised of a load, a rectifier, a PWM control module and a PWM controllable ballast. The load may be a gas discharge lamp, a motor, a heating device or a light emitting diode lamp. The rectifier is connected to a power module and rectifies a truncated sinusoidal voltage from the power module to a pulsating truncated direct current (DC) voltage. The PWM control module is connected to the power module and the rectifier and generates a PWM control signal. The PWM controllable ballast is driven by a boost circuit and is controlled by the PWM control signal that limits current to a proper value for the load.

Abstract: A voltage regulator is provided. An input node receives an input voltage. An output node provides a supply voltage. A first transistor is coupled between the input node and a node. A first resistor is coupled between the input node and a gate of the first transistor. A second transistor is coupled between the node and the output node. An amplifier includes a non-inverting input terminal for receiving a reference voltage and an inverting input terminal. A second resistor is coupled between the inverting input terminal and a ground. A third transistor is coupled between the second resistor and a gate of the second transistor, wherein the third transistor is controlled by an output of the amplifier. A fourth transistor is coupled between the third transistor and the first node, wherein a gate of the fourth transistor is coupled to the gate of the second transistor.

Abstract: In a power converter having m=two or more channels of power factor correction (PFC) circuits connected in parallel and an electromagnetic interference (EMI) filter connected in series therewith, phase shifts in switching between the respective PFC channels can allow increase of EMI filter corner frequency allowing reduction of size and cost of the EMI filter at some switching frequencies. Asymmetrical phase shifts (other than 360°/m) such as 360°/2m and other phase shifts and variations in m allow increase of EMI filter corner frequency at switching frequencies where symmetrical, 360°/m phase shifts provide no benefit to EMI filter design by providing cancellation or partial cancellation of different harmonics of the switching noise; which cancellation may be arranged to be complementary to the EMI filter function at more than one peak of the noise spectrum. (Such asymmetrical phase shifts do not significantly increase ripple and consequent switching noise).

Abstract: A power converter control system and method is provided to maximize the power output of the converter where an overload condition is present. A controller calculates a command voltage and command power factor. The command voltage and command power factor are used to generate a switching vector. Where the voltage associated with a switching vector exceeds an output voltage limit of the converter, a power factor adjustment is generated.

Abstract: This invention relates to a power supply apparatus and method for converting three-phase delta AC power to DC power using EMI filters and PFC circuits to maintain balanced AC current loading and reduce radiated and conducted emissions. Overcurrent and temperature protection are also provided in conjunction with a novel optocoupler latch circuit for improving maintenance of the power supply.

Abstract: A power supply circuit for powering a load at constant current has a rectifier stage for receiving an AC voltage input and for producing a first substantially DC voltage. A first capacitor is attached to the load. A charge-pump is attached to an output of the rectifier stage and to the load for providing power factor correction and for converting the first substantially DC voltage to a second substantially DC voltage at the first capacitor. The charge pump is prevented from conducting energy back into the output of the rectifier stage. The charge pump delivers energy to a charge pump output, the energy being delivered directly instead of being stored. A converter stage is attached to the load and the first capacitor. The converter stage is used for converting voltages at the first capacitor and the charge pump to an output DC current. The converter stage has a switch for periodically connecting a first series-coupled circuit of the charge pump to the output of the rectifier stage.

Abstract: A circuit for voltage limitation is provided in a transponder with a resonant circuit, which comprises at least one inductor, a capacitor, a depletion layer component with an input, output, and a control input, a first resonant circuit terminal, which is connected to the input of the depletion layer element, and a second resonant circuit terminal, which is connected to the output of the depletion layer element, whereby there is a connection between the control input of the depletion layer component and the first resonant circuit terminal and the second resonant circuit terminal. A method for voltage limitation in a transponder is provided, whereby for voltage limitation in the transmitting and receiving resonant circuit, the control terminal of the depletion layer element is driven by the voltage of the first and second resonant circuit terminal.

Abstract: Methods and systems for managing power are described. In one embodiment of a method, a DC input voltage from an AC mains to DC converter, inputted to a DC to DC converter, is adjusted lower while maintaining substantially constant DC output voltage from the DC to DC converter in order to improve power efficiency.

Abstract: A power factor correction method and apparatus which use Pulse Frequency Modulation (PFM) to control an AC/DC converter is disclosed. The average current drawn by the AC/DC converter is compared with a reference sinusoidal signal and the error is used to determine the switching frequency. The switching frequency varies with the sinusoidal reference signal such that the converter emulates a resistive load. By using PFM control, EMI is spread over a range rather than concentrated at a few frequencies. Since the switching frequency decreases with the loading of the converter, the switching loss decreases with the loading as well. Thus, the need of meeting efficiency standards, e.g. the 80 PLUS and Energy Star, can be fulfill without extra circuitry.

Abstract: A switching element controls supply of a primary current to a transformer in a switching power supply. An amplifier circuit amplifies an output ripple of an auxiliary winding of a transformer. A fluctuation generator circuit generates a fluctuating signal, based on an output of the amplifier circuit. A basic signal generator circuit generates a PWM basic signal whose frequency fluctuates according to the fluctuating signal. A control circuit ON controls the switching element when receiving the PWM basic signal, and OFF controls the switching element when receiving an OFF signal based on output feedback of the switching power supply.

Abstract: An example integrated circuit controller for a power converter includes a digital peak detector and a switching block. The digital peak detector is coupled to output a digital count signal representative of a peak input voltage of the power converter. The switching block is coupled to control switching of a power switch of the power converter to regulate an output of the power converter. The switching block is further coupled to control the switching of the power switch in response to the digital count signal.

Abstract: A multifunctional wall socket related to electrical conduction connecting device, comprising socket cover (1) with a conventional power connector (2) and a USB port (3) arranged on the socket cover. The USB port (3) is connected to the output terminals of an AC-DC conversion module (4) arranged on the socket cover (1). The AC-DC conversion module (4) comprises a rectifier filter module (41), modulation step-down module (42), current sampling and protection module (43), voltage reference module (44) and feedback control module (45). A first safety shutter (6) which can be opened or closed in arranged at the USB port (3) on the socket cover (1), or a second safety shutter (7) which can be opened or closed is arranged at the conventional power connector (2).

Abstract: In a system to which a fluctuating load is connected, compensating for fluctuation in voltage harmonics at the load connecting point and fluctuation in system current harmonics has been difficult for a power converting device connected in parallel with the load. To resolve the problem, a power converting device connected in parallel with a fluctuating load includes: a Fourier series expansion unit which executes Fourier series expansion to load current by use of a reference sine wave in sync with a system and thereby outputs Fourier coefficients; and a fundamental component calculating unit which calculates a positive phase active fundamental component of the load current from the Fourier coefficients. A current instruction of the power converting device is generated by subtracting the fundamental current from the load current. With the current instruction, the fluctuations in system current harmonics and in voltage harmonics at the connecting point can be compensated for.

Abstract: A method for controlling a rectifier, connected to an AC power network, of a drive converter which is provided with a load-end pulse-controlled rectifier is disclosed. An electronically controlled switch is electrically connected in parallel to every diode of the rectifier. The switching operations of the switches are produced in a manner synchronized with the conduction phases of the associated network-commutated phase voltages and independently of the phase voltages of the supply network. Every switching operation produced is released upon arrival of the next zero value at the rectifier end. The network-end switching operations are linked with the load-end zero values, thereby allowing switching operations to be carried out in a currentless manner.

Abstract: A flyback AC/DC switching converter has a constant voltage (CV) mode. The CV mode has sub-modes. In one sub-mode (“mid output power sub-mode”), the output voltage (VOUT) of the converter is regulated using both pulse width modulation and pulse frequency modulation. Both types of modulation are used simultaneously. In a second sub-mode (“low output power sub-mode”), VOUT is regulated using pulse width modulation, but the converter switching frequency is fixed at a first frequency. By setting the first frequency at a frequency above the frequency limit of human hearing, an undesirable audible transformer humming that might otherwise occur is avoided. In some embodiments, the converter has a third sub-mode (“high output power sub-mode”), in which pulse width modulation is used but the switching frequency is fixed at a second frequency. By proper setting of the second frequency, undesirable EMI radiation and other problems that might otherwise occur are avoided.

Abstract: This invention relates to an ACDC converter (1) comprising a converter input (3) and a converter output (5), a pre-regulation stage (7) and a DC transformer stage (9) comprising a transformer input stage (11) and a transformer output stage (13). The transformer input stage comprises a double ended converter and there is further provided a controller (17) for providing a control signal to the double ended converter. The controller (17) operates the ACDC converter using burst mode control and by sending control signals comprising pulse sets that are designed to provide substantially zero net magnetising current in the double ended converter. The pre-regulation stage preferably comprises a buck converter which in turn also provides power factor correction to the input of the ACDC converter.

Abstract: A reverse current control system for first power converter having a synchronous rectifier and an output inductance includes a reverse current module. The reverse current module monitors a first voltage that is based on an output voltage of the output inductance and a second voltage that is based on an input voltage of the output inductance. The reverse current module anticipates a reverse current condition based on the first and second voltages. When the reverse current condition exists, the reverse current module prevents current from flowing in reverse through the power converter.

Abstract: A power-on reset circuit connected to an external DC power source includes a delay circuit, a rectifying circuit, and a logic operation circuit. The delay circuit includes a first delay unit used for outputting a first delaying reference signal and a second delay unit used for outputting a second delaying reference signal. The rectifying circuit connected to the delay circuit includes a first rectifying unit and a second rectifying unit. The first rectifying unit is connected to the first delay circuit used for rectifying the first delaying reference signal to output a first rectified signal. The second rectifying unit is connected to the second delay circuit used for rectifying the second delaying reference signal to output a second rectified signal. The logic operation circuit is connected to the rectifying circuit used for outputting a reset signal according to the first rectified signal and the second rectified signal.

Abstract: A switching regulator (20) according to the present invention includes a sense resistor (Rs), a sense current generating circuit (213) for generating a sense current (Isense) commensurate with a sense voltage (Vsense), a slope current generating circuit (214) for generating a slope current (Islope) with a ramped or triangular waveform, a slope voltage generating circuit (215) for generating a slope voltage (Vslope) commensurate with a summed current (Isense plus Islope), an error amplifier (ERR) for generating an error voltage (Verr) commensurate with an error of an output, a comparator (CMP) for comparing the error voltage (Verr) with the slope voltage (Vslope) to generate a PWM signal and a switching control section (CTRL) for turning on and off an output transistor (N1) based on the PWM signal.

Abstract: An power converter that is operable to convert AC power into DC power that may be delivered to a load. The power converter includes a transformer and a controllable switch. The switching frequency of the power converter is configured to be dependent on the level of the AC voltage of an AC power source. The switching frequency may be proportional to the AC voltage to provide a constant magnetic flux density swing for the transformer in the power converter. The switching frequency may be controlled by using a circuit that converts the AC voltage from the AC power source into a frequency signal that is proportional to the AC voltage.

Abstract: A synchronous rectification control circuit is connected with a secondary-side rectification circuit and includes a driving circuit, a dead-time acquisition circuit, and a zero-voltage detection circuit. The driving circuit includes a differentiating circuit, a first comparator, and a capacitor, wherein the differentiating circuit generates a signal to the first comparator and the capacitor functions to charge and discharge to form a cycle. The dead-time acquisition circuit includes a second comparator and a third comparator, wherein the second comparator has a positive input connected to an output of the first comparator of the driving circuit, the second comparator has an output connected to a positive input of the third comparator, and the third comparator has a negative input connected to the output of the first comparator to acquire a dead-time signal.

Abstract: In a power converter apparatus, such as an uninterruptible power supply, a phase reference signal is generated responsive to a DC voltage on a DC bus. A magnitude reference signal may be generated responsive to a phase current of an AC bus and/or the DC voltage on the DC bus. Power is transferred between the AC and DC busses responsive to the phase reference signal and the magnitude reference signal. Generation of the phase reference signal may include generating a DC voltage error signal responsive to the DC voltage on the DC bus, generating a phase offset signal responsive to the DC voltage error signal, and generating the phase reference signal responsive to the phase offset signal. Generation of the magnitude reference signal may include generating a volt-amperes reactive (VAR) error signal responsive to the phase current and generating the magnitude reference signal responsive to the VAR error signal.

Abstract: A variable speed drive with a converter that is controllable to precharge a DC link is provided. The variable speed drive also includes an inverter. The converter converts a fixed line frequency, fixed line voltage AC power from an AC power source into DC power. The DC link filters the DC power from the converter. Finally, the inverter is connected in parallel with the DC link and converts the DC power from the DC link into a variable frequency, variable voltage AC power. The converter includes a plurality of pairs of power switches, wherein each pair of power switches includes a reverse blocking power switch connected in anti-parallel to another reverse blocking power switch. Alternatively, each pair of power switches includes a reverse blocking power switch connected in anti-parallel with a silicon carbide controlled rectifier.

Abstract: A converter power supply circuit 100 includes SW_Q1 and SW_Q2 which switch a voltage inputted from an alternating power supply 101 via a full-wave rectifier 102 and a low-pass filter 103, by drive signals applied thereto and generate an output signal; an output current detecting unit 114 which detects a current value of the output signal to a load 113; a memory 118 in which prescribed values for changing the switching operation modes of the SW_Q1 and SW_Q2 are set; and a drive circuit 116 and a control circuit 115 which detect switching currents of the SW_Q1 and SW_Q2 and continuously change the operation state of the SW_Q1 and SW_Q2 from a high power consumption state to a low power consumption state according to a comparison result of the values of the detected currents to the prescribed values in the memory 118.

Abstract: A method and circuit is provided for reducing power consumption in a power transformer, typically incorporated into an electrical or electronic device such as a consumer device. In an embodiment, a detection/isolation circuit is coupled to an input of a power transformer/rectifier via a switching device. The switching device can be, for example, a solid state relay. The detection/isolation circuit is configured to sense the occurrence of no-load conditions in the power transformer and responsively disengage the power transformer from a coupled source of power (e.g., wall outlet) via the coupled switching device.

Abstract: A synchronous regulation circuit is provided to improve the efficiency for an offline power converter. A secondary-side switching circuit is coupled to the output of the power converter to generate a synchronous signal and a pulse signal in response to an oscillation signal and a feedback signal. An isolation device transfers the synchronous signal from the secondary side to the primary side of the power converter. A primary-side switching circuit further receives the synchronous signal to generate a switching signal for soft switching a transformer. The pulse signal is utilized to control a synchronous switch for rectifying and regulating the power converter. The synchronous switch includes a power switch and a control circuit. The control circuit receives the pulse signal for turning on/off the power switch. The power switch is connected in between the transformer and the output of the power converter.

Abstract: A voltage signal rectifier produces a rectified voltage signal from an input offset voltage signal. The voltage signal rectifier includes input offset, output, and reference nodes, two actively controlled current regulation elements (ACCREs), and two controllers. The input offset node is coupled to the input offset voltage signal. The rectified voltage signal is generated onto the output node. The reference node is coupled to a reference voltage for the input offset and rectified voltage signals. The ACCREs are coupled to the input offset node and one of the ACCREs is coupled to the output node. Each controller is configured to control the one of the ACCREs so that the ACCRE coupled to the output node allows current flow through it when the input offset voltage signal is higher than the rectified voltage signal and the other ACCRE is configured to allows current flow through it when the input offset voltage signal is lower than the rectified voltage signal.

Abstract: This invention relates to a power converter (1) comprising a converter input (3), a converter output (5), a power factor correction (PFC) stage (7) and an isolation stage (9). The PFC stage (7) is implemented by way of a buck PFC with low side drive and low side current sensing, There is provided a third stage, an intermediate buck pre-regulation stage (11), intermediate the buck PFC stage (7) and the isolation stage (9), Control of the power converter output voltage is achieved by varying the duty cycle of the intermediate buck pre-regulation stage (11) and therefore the isolation stage (9) may be an unregulated stage operated as a fixed DCDC voltage converter. The isolation stage (9) is operated as a 50%-50% duly cycle double ended stage. The configuration of power converter allows for a relatively inexpensive, highly efficient converter with 90%+ efficiency and simplified control.

Abstract: Detection and control circuitry are added to a conventional power supply to detect when a load, such as a portable electronic device, has been disconnected from the power supply and, when disconnected, interrupt a current path to the primary windings of a transformer within the power supply to substantially reduce the amount of reactive power that is consumed by the power supply.

Abstract: A driver circuit included in a power supply having a rectifier coupled to a single phase AC input voltage is disclosed. An example driver circuit includes a drive signal generator to generate a drive signal to be coupled to a variable impedance element. A voltage sensor is coupled to the drive signal generator and is to be coupled to sense a voltage across a high voltage capacitance. The driver circuit is to be coupled to control the variable impedance element in response to the voltage sensor. A low voltage capacitance is allowed to receive current from the input if the sensed voltage is less than a second threshold value. The low voltage capacitance is prevented from receiving current from the input if the sensed voltage is greater than a first threshold value.

Abstract: A high voltage rectifier device exhibiting low forward resistance and fast switching time formed of a high voltage structure connected in a cascode configuration with a low voltage structure. The high voltage structure is a bidirectional normally on semiconductor switch have two pairs of gate and source terminals which shuts off if either of the gate terminals is reverse biased. The low voltage structure is a diode, preferably a Schottky or barrier diode. The device is advantageously formed as an integrated circuit. With one of the terminal pairs of the switch clamped to zero volts, the device behaves as a diode, or the second terminal pair can be employed to provide the functions of a three terminal controlled rectifier. Among other possible applications are integrated circuits using four of the devices as a bridge rectifier, and as an anti-parallel diode for connection with an IGBT.