Abstract: A circuit for driving a communication line includes a transformer having a secondary winding for supplying an output drive signal, and having a primary winding connected to conduct current through a control element that receives a control signal which stabilizes the amplitude of output drive signal, independent of variations in supply voltage. A control circuit produces the control signal in response to the difference of signals produced across conductive elements that are connected to separate current sources which supply currents determined by arithmetic relationships between the values of different supply voltages.

Abstract: A junction box (10) is constituted by a junction box body (14), on which a fuse outlet (11e) is formed, and a casing (18) for housing the junction box body (14). The casing (18) is formed by a lower case (17) for housing the junction box body (14), and an upper case (16) for detachably covering a housing hole (17i) of the lower case (17). A cutaway portion for exposing the fuse outlet (11e) is formed on the lower case (17). Moreover, a closing portion (16d) for covering the cutaway portion is provided on the upper case (16).

Abstract: A connection box includes a wiring board. The box includes a control board connected to the wiring board. The control board including a control device and another device separated thereinto. Another device has generation heat greater than the control device.

Abstract: A circuit configuration combining a synchronous rectifier (SR) circuit for a converter with an LC snubber circuit is characterized in that the converter includes a transformer, a secondary coil of which being connected at an end to a metal oxide semiconductor field effect transistor that is parallelly connected to a resistance and a capacitance that are serially connected to each other, in order to reduce oscillation and electromagnetic interference; and that a primary coil of the transformer is serially connected at two ends to two diodes, an inductance is connected between the two diodes, and a connection end of the inductance to one of the two diodes is connected to a junction of the transformer and a main switch via a capacitance to form the LC snubber circuit. In this way, the transformer of the converter may be reset to enable regeneration of energy and upgraded efficiency of the converter.

Abstract: A regulated self-supply power controller for a switched-mode power supply includes an operational voltage supply line having a voltage magnitude that varies between two voltage magnitudes. A controllable power source is intermittently coupled to a capacitor, which is coupled to the operational voltage supply line, on the basis of the variation of the operational voltage supply line voltage magnitude between the two voltage magnitudes.

Abstract: A horizontal drive circuit employed in CRT displays which uses a switch-mode power supply operating in a boost topology to generate the appropriate supply voltage needed by the horizontal drive circuit is provided. The boost power supply is integrated into the horizontal drive circuit which allows for low printed circuit board area, low cost, and good performance over many different horizontal frequencies.

Abstract: The invention relates to a semiconductor circuit having a drive circuit, a load that is disposed between a supply voltage, and a controllable, clocked semiconductor switching element for clocked switching of the load. The invention furthermore relates to a switch-mode power supply having such a semiconductor circuit.

Abstract: A load-dependent frequency modulation circuit and a method thereof for a switching power system. The load-dependent frequency modulation circuit has a control integrated circuit, a feedback circuit and a clock control generator. The control integrated circuit has a clock signal generation terminal and a feedback input terminal. The clock signal generation terminal is used to generate a clock signal. The feedback circuit processes the output of the switching power system, and feedbacks the processed feedback signal to the feedback input terminal. The clock control generator is electrically connected to the feedback input terminal. According to the control signal generated by variation of the feedback signal, the clock frequency at the clock signal generation terminal is adjusted.

Abstract: A transformer connected to a power source, which consists of a primary coil, a secondary coil and a magnetic core, the secondary coil being configured to provide a regulated DC output voltage and/or current. The primary coil contains two portions, one portion being used to operate the transformer as a low voltage input converter and both portions being used when the transformer is used as a high voltage input converter.

Abstract: A power converter apparatus, such as a DC-DC converter, includes a switch that controls current transfer between an input port and an inductance. A control circuit is operative, while current is being transferred between the inductance and a clamping circuit, to control the switch responsive to a current in the inductance. For example, the control circuit may include a current sensor configured to be coupled in series with the inductance and a switch control circuit operative to control the first switch responsive to a current sense signal generated by the current sensor. The switch control circuit may be operative to prevent transition of the switch from the first state to the second state until the current sense signal meets a predetermined criterion, e.g., a signal state indicative of a desired current condition, such as a current approximating zero or a current reversal. Related operating methods are also discussed.

Abstract: A switched-mode power supply has a storage capacitor, a transformer with a primary winding and at least one secondary winding, and also a switching transistor which is connected in series with the primary winding. The primary winding is subdivided into sub-windings with at least one tap. A capacitance is disposed in parallel with each sub-winding, as a damping network. The numbers of windings of the sub-windings and the values of the capacitors disposed in parallel with the sub-windings are selected in such a way that the oscillations occurring when the switching transistor becomes blocked have different resonant frequencies and thereby partially cancel each other. This results in an effective damping of the resonant voltage over the switching transistor. Since the capacitors are connected in series, the effective total capacitance is low, so that the resulting discharge current at the time when the switching transistor becomes conductive is comparably low.

Abstract: The invention has a first series circuit consisting of a capacitor and a diode and a second series circuit consisting of a coil and a diode, the first series circuit is connected in parallel to the commutating diode in a state that the capacitor is connected to a choke coil side in the commutating diode, and the second series circuit is connected between a connecting portion of the capacitor and the diode in the first series circuit and a commutating diode non-connecting side in the choke coil.

Abstract: A magnetic core for use in a saturable reactor made of an Fe-based soft-magnetic alloy comprising as essential alloying elements Fe, Cu and M, wherein M is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, and having an alloy structure at least 50% in area ratio of which being fine crystalline particles having an average particle size of 100 nm or less. The magnetic core has control magnetizing properties of a residual operating magnetic flux density &Dgr;Bb of 0.12 T or less, a total control operating magnetic flux density &Dgr;Br of 2.0 T or more, and a total control gain Gr of 0.10-0.20 T/(A/m) calculated by the equation: Gr=0.8×(&Dgr;Br−&Dgr;Bb)/Hr, wherein Hr is a total control magnetizing force defined as a control magnetizing force corresponding to 0.8×(&Dgr;Br−&Dgr;Bb)+&Dgr;Bb.

Abstract: A charging device capable of dynamically adjusting a charging power. The charging device has elements as follows. A DC-DC converter power stage is used for supplying a charging current to the rechargeable battery. A current error amplifier is used for setting a charging current adjustment signal, being fed to the DC-DC converter power stage for adjusting the charging current. A first current detecting device is used for setting the charging current signal being fed to the current error amplifier. Meanwhile, the charging current is outputted to the rechargeable battery to charge the rechargeable battery A current detecting/comparating device is used for setting and outputting the work current operation signal based upon the work current and a work current setting signal. The charging device dynamically adjust the charging power to increase the utility of the output power of the external power source and reduce the charging time.

Abstract: A DC/AC converter is provided for contactless, inductive transfer of energy, which transfers arbitrary voltages to a removable user with the aid of a high-frequency pulse generator. The pulse generator produces asymmetric pulses, which provides two different voltages to the user, depending on a to coupling orientation. Further, the pulse generator is built in such a way that, if a user is absent, it is not excited to oscillation and, as a result, uses substantially no energy at all in a stand-by operation.

Abstract: A magnetic device, method of manufacture therefor and a power supply employing the magnetic device. In one embodiment, the magnetic device includes a metal substrate and a first dielectric layer formed over the metal substrate. The magnetic device further includes a first conductive layer formed over only a portion of the dielectric layer and a magnetic core mounted proximate the first conductive layer adapted to impart a desired magnetic property thereto.

Abstract: The invention relates to a semiconductor circuit having a drive circuit, a load that is disposed between a supply voltage, and a controllable, clocked semiconductor switching element for clocked switching of the load. The invention furthermore relates to a switch-mode power supply having such a semiconductor circuit.

Abstract: A control apparatus controlling a DC/DC converter. The control apparatus switches on and off switching devices to transfer the electric power from a main storage battery to an auxiliary battery. The control apparatus includes a control circuit controlling the switching on and off, a voltage monitor detecting the over and under voltage of the main storage battery, and a gate drive circuit, including a driving transformer, driving the switching devices. The control apparatus utilizes the large current, which flows on the control circuit side of the driving transformer by short-circuiting the output side of the transformer in response to the detected over or under voltage, to transfer the isolated signal indicating the main storage battery voltage to the control circuit side. The control apparatus is more reliable than conventional control apparatuses, which employ a photo-coupler to transfer the isolated signal to the control circuit side.

Abstract: The present invention relates to electronic converters having an input circuit and an output circuit which, in addition to their converter function, carry out power-factor correction. They comprise a control circuit which opens and closes an electronic switch, to be precise as a function of the output voltage from the converter circuit and the voltage which is dropped across a current measurement sensor. The invention is distinguished in that the circuit has a logic ground LM and a power ground PM at different electrical potentials.

Abstract: A power supply controller having a multi-function terminal. In one embodiment, a power supply controller for switched mode power supply includes a drain terminal, a source terminal, a control terminal and a multi-function terminal. The multi-function terminal may be configured in a plurality of ways providing any one or some of a plurality of functions including on/off control, external current limit adjustments, under-voltage detection, over-voltage detection and maximum duty cycle adjustment. The operation of the multi-function terminal varies depending on whether a positive or negative current flows through the multi-function terminal. A short-circuit to ground from the multi-function terminal enables the power supply controller. A short-circuit to a supply voltage from the multi-function terminal disables the power supply controller. The current limit of an internal power switch of the power supply controller may be adjusted by externally setting a negative current from the multi-function terminal.

Abstract: An asymmetrical full bridge DC-to-DC converter comprises an asymmetrical full bridge circuit which includes main switches and auxiliary switches, a capacitor connected in series to the branch circuit of the auxiliary switches, and a transformer having a primary winding and a secondary winding. The primary winding of transformer is connected to the common point of each leg of the full bridge. A rectification circuit is connected at the secondary winding of the transformer to obtain dc voltage output. In operation, an asymmetrical control method is applied for these main switches and auxiliary switches. Main switches and auxiliary switches turn on and turn off compensatively. A linear control characteristic of output voltage to switching duty cycle and an optimal reset of the transformer core is achieved by this invention.

Abstract: A series circuit of a primary winding 1 A of a transformer 1 and a switching element 2 is coupled to a DC source 3 and a voltage induced in a secondary winding 1B of the transformer 1 according to switching operation of the switching element 2 is rectified and smoothed by a rectifier smoothing circuit 9. Further, a Zener diode 21 is coupled across the switching element 2 with reverse polarity to the switching element 2. The Zener diode 21 may be coupled across a rectifier diode 5 which conducts during the ON period of the switching element 2.

Abstract: A power supply having a mixed regulator is able to provide the suitable power source according to the changing load by a switching mode voltage circuit and a series pass controlling circuit. The series pass controlling circuit has high sensitivity in detecting the changing the load, thus the power supply offers the suitable power source according to the changing of the load. The switching mode voltage circuit controls the transformer to output voltage by a PWM IC, so that the transistors for driving the transformer need not be powerful transistors which generate excessive heat. Thus a heat sink is not necessary and the power supply can accordingly be of a compact size.

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: The invention concerns a dc-to-dc converter controlled by a rectangular signal comprising an input for a direct voltage source (VDC), a transformer comprising a primary coil (1) connected to the direct voltage source (VDC) and a D2 secondary coil (2), a single switch (S) series-connected with the primary (1) and the direct voltage source (VDC), an output comprising the transformer secondary (2) and at least a tertiary coil (3) located in the proximity of the primary (1) and secondary (2) coils at the transformer core series-connected with a first diode (D1).

Abstract: A method for reducing harmonic distortions and switching losses in a power factor correction circuit of a quasi-resonant voltage converter, wherein using data derived from the sensing a voltage impressed on the switching device in the power converter, a multitude of event times can be calculated that will align the timings of the drive circuitry of the power converter to those of the natural resonance transitions of reactive elements of the converter. An over-sampling of the voltage impressed on the switching device voltage allows accurate sensing of a “zero-current” cross-over condition in an inductance of the converter.

Abstract: An electronic equipment for onboard process control includes a first detection stage with a plurality input circuits, comprising each a first transformer having a primary coil connected to the corresponding input via a first hashing transistor, and a secondary coil connected to a diode rectifier circuit. A first clock sends control signals to the first hashing transistor. Adjusting means cooperate with the first clock for adjusting the frequency of the control signals or the cyclic ratio for adapting the voltage of said input circuit. A logic level detector is inserted in the secondary circuit of the first transformer, and is electrically connected to an acquisition circuit. A second recovery stage is connected to a battery supplying the equipment for restoring the energy drained by the input circuits of the first detection stage.

Abstract: Power semiconductor switching devices, power converters, integrated circuit assemblies, integrated circuitry, power current switching methods, methods of forming a power semiconductor switching device, power conversion methods, power semiconductor switching device packaging methods, and methods of forming a power transistor are described.

Abstract: A power supply provided with: an AC/DC converter which receives AC power, converts the AC power into DC power, and outputs the DC power; a DC/DC converter which receives the DC power from the AC/DC converter, and controls a level of an output voltage of the DC/DC converter to be equal to a level of a voltage to be used by a load while the DC/DC converter supplies the output voltage to the load; a DC converter which is connected to an input of the DC/DC converter; and a DC power storage means which supplies electric power to the DC/DC converter through the DC converter.

Abstract: A constant-frequency active filter controlled by a peak current control mode, the constant-frequency active filter composes of a voltage step-up unit and a power factor corrector, wherein the power factor corrector is composed of a voltage control loop and a current control loop. The voltage step-up unit adjusts a waveform of an input current to a sine waveform. The voltage control loop has a microprocessor that provides a current command having the same phase with an input voltage to a PWM controller of the current control loop. The current control loop provides a sensing current induced from the input current to the PWM controller. The PWM controller receives the sensing current and the current command to control the input voltage and the input current to become the same phase so as to obtain a high power factor.

Abstract: A technique, which substantially reduces the number of power-stage and control circuit components in an isolated DC/DC converter with parallel current-doubler rectifier stages, includes on the primary side transformers with serially connected primary windings each having a corresponding secondary winding coupled to one of the voltage-doubler stages. In one embodiment, the primary and secondary windings and filter inductors of the current-doubler rectifier stages are provided on an integrated magnetic core. The filter inductors in each current-doubler rectifier stage can be provided as coupled inductors. In one embodiment, an X-shaped magnetic core is provided to achieve coupled or uncoupled filter inductors.

Abstract: The inverter circuit can be structured by a simple structure as follows: an inductive element (the primary winding) 23 whose one end is connected to a DC power source 21; the first capacitor 24 connected in parallel with it; a serial circuit of the second switching element 27 and the second capacitor 25; a common connection point to which the primary winding 23, the first capacitor 24, and the other end of the serial circuit are connected; and the first switching element 26 to open and close control between the DC power source 21 and the other portion, are provided, and a drive signal generating means (resistance) is connected between the control terminal of the second switching element 27 and the common connection point.

Abstract: An impedance network for passive shoot-through protection of active switches in clamp-mode topologies. In one exemplary embodiment a switch-mode converter, includes: a primary switch; an auxiliary switch coupled in series with a capacitor; and an impedance network, coupled to the primary switch and the auxiliary switch; configured to limit current during simultaneous conduction of the primary and auxiliary switches. The impedance network includes a resistor coupled in series to a diode and both in parallel with an inductor. The impedance network permits the design of a clamp-mode converter without the need for a delay between switch turn-off and turn-on of primary and auxiliary switches.

Abstract: A synchronous rectifier is disclosed, which makes use of gate charge retention technique. In a forward converter after the main transformer is reset its secondary voltage diminishes to zero. For self-driven synchronous rectifiers the driving voltage is lost and current is forced to go through body diode with high conduction loss. Active clamp is a method to get around the problem but it requires an active switch on the primary side. The present invention introduces gate charge retention method by, which no additional active switch is required on the primary side. Synchronous rectifiers are kept on even after the main transformer is reset and secondary voltage diminished to zero. This synchronous rectifier avoids effect of leakage inductance in converter transformer windings and operates at high efficiency. This synchronous rectifier can operate in a number of circuit topologies.

Abstract: The present invention of a power supply and battery back-up system includes an AC/DC power supply and a battery for supplying operating power to a telecommunications system. The battery is connected to the telecommunications system and is designed to supply the telecommunications system with operating power if the power supply fails for some reason. The power supply is designed to output the peak operating power required by the telecommunications system, supplying the telecommunications system with whatever operating power it needs and supplying the difference between the operating power supplied to the telecommunications system and the peak operating power output by the power supply to the battery for charging. In one embodiment, the battery back-up system includes a battery monitoring circuit for monitoring the battery voltage and a relay connected between the battery and the telecommunications system for disconnecting the battery if the battery voltage falls below a pre-set level.

Abstract: A power supply system is disclosed. The circuit comprises a main power supply portion, the main power supply portion including a transformer, and an auxiliary power supply portion wherein the auxiliary power supply portion is coupled to the main power supply portion via the transformer. Through the use of the power supply system in accordance with the present invention, the auxiliary output voltage is generated by the main power supply. Therefore, the present invention provides the auxiliary output voltage supply by using the same pulse width modulator and switching devices as used by the main power supply. The use of a power supply system in accordance with the present invention thereby eliminates the need for the components required to maintain the auxiliary output voltage.

Abstract: A rectified commercially available power source is supplied to one end of a primary coil T1 of a transformer T through a terminal TM1. A capacitor C for rectifying is provided between the terminal TM1 and the ground. A switching device X is provided between the other end of the primary coil T1 and the ground. A power source obtained from a terminal TM3 is supplied as a power source for driving oscillators O1 and O2, PWM circuits P1 and P2, and a driving circuit D. The oscillator O1 supplies a signal based on a preset frequency f1 to the circuit P1. In the circuit P1, a switching signal having a predetermined duty ratio according to the supplied signal is supplied to the circuit D through a switching circuit SW1. In the circuit D, the supplied switching signal is amplified and supplied to a control terminal of the switching device X.

Abstract: A microcomputer reset device includes a switching circuit for comparing, after a reset of a CPU is released during power-up, a reference voltage Vref with a second divided voltage Vd2 which is proportional to a supply voltage and is adjusted by the CPU, and for switching, when the second divided voltage Vd2 exceeds the reference voltage Vref, a clock source of the CPU from an internal clock signal to an external clock signal. This makes it possible to solve a problem of a conventional microcomputer reset device in that it is not unlikely that the microcomputer starts its operation before its reset has been completed, which hinders the normal operation of the microcomputer.

Abstract: The switching power supplies convert AC or DC input voltage into a DC output voltage. Conventional topologies are implemented, wherein power factor correction and/or square-wave switching at resonant transition is accomplished. In a front-end, rectified line voltage is applied to an inductor that attains line current. A diode limits voltage at a front-end output to a holdup voltage stored in a capacitor. A switch selectively applies the holdup voltage to the front-end output. In a DC/DC power supply, a switch selectively applies the input voltage to an inductor that attains a current. A transformer provides primary and secondary voltages in response to the current. A voltage across the inductor is limited to the primary voltage that is stored in a capacitor. The secondary voltage is rectified and applied to another capacitor that provides the DC output voltage. No output inductor is required. Furthermore, a forward power supply employs a single output diode.

Abstract: The switched-mode power supply has a storage capacitor, a transformer with a primary winding and at least one secondary winding, and also a switching transistor which is connected in series with the primary winding. The primary winding is subdivided here into sub-windings with at least one tap, and a capacitance is in each case disposed in parallel with sub-windings, preferably with each sub-winding, as a damping network. The numbers of windings of the sub-windings and the capacitances of the capacitors disposed in parallel with the sub-windings are selected in such a way that the oscillations occurring when the switching transistor is deactivated have different resonant frequencies and thereby partially cancel each other out. This results in an effective damping of the deactivation voltage over the switching transistor.

Abstract: A switching power converter of the present invention, wherein a series circuit comprising the primary winding 31 of a transformer and a first switch 2 is connected in parallel with a DC input power supply 1, and a series circuit comprising a capacitor 8 and a second switch 7 is connected in parallel with the primary winding 31; the switching power converter is provided with a first control drive circuit 9 for alternately turning on/off the first switch 2 and the second switch 7 so as to have an on-period, an off-period and a rest period, and a second control drive circuit for turning on/off the third switch 41 connected to the secondary winding 32 of the transformer, whereby the current flowing through the secondary winding of the transformer has a resonance waveform.

Abstract: The switched-mode power supply comprises a transformer, a switching transistor connected in series with a primary winding of the transformer, a primary-side control circuit and a secondary-side regulating stage. The regulating stage is coupled to a coupling element for transiting a regulating signal from the secondary side to the primary side. A first switch is situated between the control input of the switching transistor and a primary-side operating voltage, and a second switch is situated between the regulating stage and a secondary-side operating voltage, with the two operating voltages being able to be disconnected using a single control signal. In this case, the isolating element transmits both the regulating information for the primary-side control circuit and the turn-off signal for the first switch. If the second switch is turned off by the control signal, the regulating stage and the optocoupler become completely currentless and consume no further power.

Abstract: A power control circuit for controlling an output of a power supply is provided with a setting section which variably sets a maximum rated output based on input temperature information.

Abstract: A power supply circuit (120) for supplying power to a load (130) comprises a regulator (122), a switching transistor (124) connected to the regulator; and a power transformer (126) connected between the switching transistor and the load. The regulator is of a type that requires feedback regarding the amount of voltage supplied to the load. In accordance with the present invention, a feedback signal to the regulator is generated by monitoring an input to the power transformer. In particular, a voltage signal related to a voltage on the primary of the power transformer after a voltage spike is applied as the feedback signal to the regulator. A peak detector (140) detects the to voltage spike and applies the voltage signal to the regulator. A peak detector reset circuit (142) resets the peak detector. In one example context of usage, a variable air gap exists between a stationary primary of the power transformer and a secondary of the power transformer.

Abstract: Universal switched power converter having a transformer that comprises a first winding (11-3) divided into two parts and having an intermediate tap (11-3-1), and a second winding (11-9) connected in cascade with rectifier means (12) and filter means (13), so that a first current flows through the part of said first winding (11-3) comprised between the end of the primary winding (11-3) connected to a first input terminal (11-1) and the intermediate tap (11-3-1) and through a second switching element (11-6) connected to the intermediate tap (11-3-1) and to a second input terminal (11-2), when the input voltage applied across the input terminals (11-1, 11-2) is close to a first predetermined voltage value and the second switching element (11-6) is in a conducting state.

Abstract: A forward converter incorporating a low loss snubber and transformer reset circuit is disclosed. The transformer core of the forward converter is reset by the exchange of magnetizing energy between the transformer secondary winding and an appropriately sized capacitor of the reset circuit during the off period of the power switch. The exchange of magnetizing energy from the capacitor to the transformer secondary winding is independent of power switch operation.

Abstract: A rectified commercially available power source is supplied to one end of a primary coil T1 of a transformer T through a terminal TM1. A capacitor C for rectifying is provided between the terminal TM1 and the ground. A switching device X is provided between the other end of the primary coil T1 and the ground. A power source obtained from a terminal TM3 is supplied as a power source for driving oscillators O1 and O2, PWM circuits P1 and P2, and a driving circuit D. The oscillator O1 supplies a signal based on a preset frequency f1 to the circuit P1. In the circuit P1, a switching signal having a predetermined duty ratio according to the supplied signal is supplied to the circuit D through a switching circuit SW1. In the circuit D, the supplied switching signal is amplified and supplied to a control terminal of the switching device X.

Abstract: The invention relates to a circuit for transforming, switching, adjusting or controlling electric power, comprising an electric source 1, a load 2, and a device 3 for transforming, switching, adjusting or controlling the electric power resulting on the load 2. To reduce the losses, it is provided that the device 3 is formed by at least one transformer 10, 10′, whose secondary side overlays the source 1 and whose primary side is connected with a control device 11, whereby at certain points of time and for certain periods of time, a voltage or a current can be produced at the primary side of the transformer 10, 10′, which voltage or current induces a voltage or a current, respectively, at the secondary side of the transformer 10, 10′, which voltage or current, respectively, is equal to the voltage or current, respectively, of the source 1 at this point of time and for that period of time.

Abstract: An integrated circuit has a MOSFET comprising a drain terminal, a source terminal and a gate control terminal, the MOSFET having an equivalent circuit that includes an intrinsic diode; and a diode comprising an anode terminal and a cathode terminal.

Abstract: A synchronous rectifier for use with a clamped-mode power converter uses in one embodiment a hybrid rectifier with a MOSFET rectifying device active in one first cyclic interval or the conduction/nonconduction sequence of the power switch and a second rectifying device embodied in one illustrative embodiment as a low voltage bipolar diode rectifying device active during an alternative interval to the first conduction/nonconduction interval. The gate drive to the MOSFET device is continuous at a constant level for substantially all of the second interval which enhances efficiency of the rectifier. The bipolar rectifier device may also be embodied as a MOSFET deice. The subject rectifier may be used in both forward and flyback power converters.