Abstract: This invention relates to control techniques and controllers for resonant discontinuous forward power converters (RDFCs). We describe a controller for a resonant discontinuous forward converter (RDFC), said forward converter including a transformer with first and second matched polarity windings and a switch to switch dc power to said first winding of said transformer, said converter further having a dc output coupled to said second winding of said transformer, and wherein said controller has two modes, a first operational mode during which said switch is controlled to switch said dc power at a frequency which substantially coincides with a resonant frequency of operation of said RDFC such that said RDFC supplies power from said dc output, and a second, reduced power operational mode during which a drive to said switch is controlled to increase a proportion of time during which said switch is off.

Abstract: A control circuit for a switch unit of a clocked power supply circuit, the switch unit being designed to effect input-side excitation of a resonant transformer arrangement, comprises an input for receiving an auxiliary signal from the resonant transformer arrangement. The auxiliary signal exhibits an essentially fixed phase relation to a load alternating current flowing through a resonant circuit of the transformer arrangement. The control circuit further comprises a phase detector designed to detect reference crossing moments when the auxiliary signal crosses a predefined reference value, a driver controllable to switch the switch unit, and a synchronization means designed to synchronize a turn-on of the switch unit by the driver with regard to a phase position with the auxiliary signal so as to achieve a turn-on of the switch unit within a predetermined time interval around a zero crossing of a voltage present across the switch unit, or of a current flowing through the switch unit.

Abstract: A resonant switching power converter having adaptive dead time control provides improved efficiency along with reduced EMI/audible noise and component stresses. A dead time between pulses generated by a switching circuit is adaptively set in conformity with a value of the input voltage to the resonant switching power converter and an indication of a magnitude of the current passing through inductive element of the resonant tank of the converter. The indication of the current magnitude may be the switching frequency of the converter, or a measure of line or load current levels. The dead time can be obtained from a look-up table or computed from the current magnitude and input voltage values.

Abstract: The subject invention reveals a new three terminal canonical cell for non-isolated power conversion. The canonical cell achieves reduced semiconductor component stresses for applications with limited line voltage range for small step up and step down ratios or for large step up and step down ratios. Some of the canonical cells can be used to form buck, boost, and buck boost converters. The new canonical cell achieves zero voltage switching over a broad range of line and load voltages and is self limiting without the addition of additional components to sense and respond to over load current.

Abstract: A half-bridge resonant converter including a half-bridge switching circuit, a resonant circuit and a rectifier circuit is provided. The half-bridge switching circuit is controlled by two control signals for alternatively coupling two terminals of a DC power source to an input of a resonant circuit. The control signals have the same frequency and duty cycle, and one of the control signals is delayed a period by the other one, in which the frequency of the control signals is constant and the duty cycle of the control signals is variable according to a load. The rectifier circuit generates an output voltage across the load from an output of the resonant circuit. Therefore, the resonant converter of the present invention has the advantage of constant frequency operating and at least one of the two switches operated in ZVS.

Abstract: A resonance converter and a synchronous rectification driving method thereof are provided. The resonance converter includes a switch circuit having at least two first switches, a resonance circuit having a resonance frequency, a transformer, and a full-wave rectification circuit having two second switches each of which has a drain and a source and generates a channel resistance voltage when a current flows through the drain and the source. The synchronous rectification driving method includes steps as follow.

Abstract: A control method is proposed that enables to drive a resonant (LLC) power converter at low loads with substantially reduced power losses for realizing a stand-by power. The reduction is achieved by a sub-critical operation several times below Resonance Frequency while still keeping zero voltage switching. One half-bridge switch (s1) is turned on for a short pulse—in the remaining time of the sub-critical switching period the resonant current oscillates through the other switch (s2). Zero voltage switching is obtained by evaluating the resonant capacitor voltage. The pulse length determines the stand-by power and is used as controlling variable. The power supply is suitable for Consumer Electronics products that require a low power standby supply.

Abstract: A discontinuous resonant forward power converter including a controller having an output coupled to a controllable switch and which is configured to control the switch such that a voltage waveform on a secondary winding of a transformer of the converter has a first portion during which the switch is on and current flows into an output node of the converter which is coupled to the output rectifier and to a smoothing capacitor, and which has a second substantially resonant portion during which the switch and an output rectifier are both off. Substantially no current flows into the output node during the second portion of said voltage waveform.

Abstract: In one embodiment, a power supply controller is configured to switch a power switch of a power supply when a voltage across the switch is at a minimum value.

Abstract: A driving circuit for providing a control signal to a power semiconductor device for providing power to a filament lamp, said driving circuit comprising an oscillator for generating said control signal. The driving circuit may further comprise a soft start circuit which controls said oscillator so as to avoid excessive current in said lamp at start-up; a voltage compensation circuit which controls said oscillator so as to compensate for variations in load; a shutdown circuit for shutting down and automatically restarting said oscillator in response to a fault condition; an adaptive dead time circuit which controls said oscillator for providing cool running of said power semiconductor device; and/or a dimming circuit which controls said oscillator for driving said lamp. The driving circuit and its control circuitry may be implemented in an integrated circuit.

Abstract: A primary winding 5a of a transformer T and a switch Q1 are connected in series with a DC power source Vdc1. A series circuit composed of a switch Q2 and a snubber capacitor C3 is connected in parallel with the primary winding or the switch Q1. A saturable reactor SL1 is connected in parallel with the primary winding 5a. A series circuit composed of a diode D1 and a capacitor C4 is connected in parallel with a secondary winding 5b of the transformer T, to form a rectifying/smoothing circuit. A control circuit 10 turns on and off the switches Q1 and Q2 alternately and turns off the switch Q2 when a current to the switch Q2 increases.

Abstract: A switching power supply that can accurately detect a period during energy is supplied from a primary side to a secondary side of a transformer with a simple circuit configuration is provided. A first switching element and a second switching element are serially connected to opposite output ends of a full-wave rectifier rectifying an AC voltage from an AC power source. A current resonant capacitor, a resonant reactor, and a primary winding of a resonant transformer are serially connected to opposite ends of the first switching element.

Abstract: A radio frequency (RF) generator comprises a first half bridge including first and second power transistors; a second half bridge including first and second power transistors; an RF output node coupling output nodes of the first and second half bridges, the output node outputting RF signals to a load; positive and negative rails coupled to a power source; and a first commutation inductor provided to store energy to commutate at least one of the half bridges.

Abstract: A circuit arrangement comprising a high-side semiconductor switch with a first load terminal connected to a first supply terminal receiving an input voltage, a second load terminal connected to an output terminal providing an output signal, and a control terminal, a floating driver circuit connected to the control terminal for driving the semiconductor switch, a level shifter receiving an input signal and providing a floating input signal dependent on the input signal, a floating control logic receiving the output signal and the floating input signal and providing at least one control signal to the floating driver circuit, wherein the floating control logic comprises means for detecting an edge in the output signal and means for generating the control signal dependent on the result of the edge detection.

Abstract: The present invention provides a power converter having a phase lock circuit for quasi-resonant soft switching. The power converter includes a first circuit coupled to the feedback signal to generate a switching signal for switching a switching device and regulating the output of the power converter. A second circuit is coupled to an auxiliary winding of the transformer for generating a voltage signal in response to the voltage of the transformer. A phase lock circuit generates a control signal to enable the switching signal in accordance with the voltage signal. The switching signal further turns on the switching device in response to a valley voltage across the switching device.

Abstract: A forward-forward converter (FFC) and method of operation thereof. The FFC has a first transformer, including a primary winding coupled to power and clamp switches and a secondary winding coupled to the primary winding, configured to provide an output energy transfer of the forward-forward converter during conduction of the power switch. The FFC also has a second transformer, including an input winding coupled to the secondary winding, configured to form an intermediate circuit mesh and extend zero-voltage switching opportunity and the output energy transfer, through the outputs windings coupled to the input winding, during conduction of the power and clamp switches.

Abstract: The provided switching power supply includes an auxiliary circuit having an auxiliary switch and a auxiliary capacitor, a transformer having a primary side coupled to the auxiliary circuit in parallel and a secondary side, an auxiliary switch control circuit coupled to the auxiliary switch and the primary side and fixing a turn-on time of the auxiliary switch, a main switch coupled to the primary side, a ZVS detector coupled to the main switch, a first and a second rectifying switches coupled to the secondary side and a filter circuit coupled to the second rectifying switch in parallel. The provided method includes the steps of: (a) fixing the turn-on time of the auxiliary switch; and (b) generating a fixed turn-off time of the main switch accordingly so as to accomplish ZVS of the main switch.

Abstract: The switched mode power supply comprises an inductor, a switching transistor coupled in series with the inductor, and a rectifier circuit. The rectifier circuit comprises a switch coupled with the inductor for a rectification of an output voltage and a control circuit operating in a monostable mode. The switch is operated in particular in a synchronous mode with the same switching frequency as the switching transistor. The rectifier circuit can be used advantageously with a switched mode power supply having a push-pull half-bridge configuration and operating as a resonant converter or a quasi-resonant converter with soft switching for an application within a plasma television set.

Abstract: Implementations related to controlling of a switch in a DC-DC converter are presented herein.

Abstract: A method and apparatus to magnetically couple AC power from the high voltage electric utility power line current induced magnetic field over a wide voltage and current range to provide a low voltage, low current DC power supply useful in powering other remotely located or limited accessibility circuitry requiring low voltage DC power to operate.

Abstract: A power factor controller for a switching power supply, that in one embodiment couples a power factor control circuit between an AC input and an output wherein a digital controller computes circuit currents for regulating the power supply without direct current measurements.

Abstract: The present invention relates to a switch mode power supply and a driving method for reducing switching loss and audible noise in the burst mode. The switch mode power supply includes a main switch, a power supply, an output unit, and a switch controller. The power supply includes a transformer having a primary coil connected to the main switch, and supplies power to a secondary coil of the transformer according to the operation of the main switch. The output unit is connected to the secondary coil of the transformer and outputs power supplied to the secondary coil of the transformer.

Abstract: The invention finds application in the field of power supplies for valve actuators, and particularly relates to a wide voltage range stabilized switching power supply for valve actuators, of the type that comprises a filter 2, a diode bridge 3, an array of capacitors 5, an auxiliary power supply stage 6, formed by a switch mode circuit, having an operating range of 21 to 380 VDC, which generates the supply voltages required for the internal operation of the power supply, a full-bridge power stage 7, which receives an input voltage in the range of 120 VDC to 373 VDC, and generates the three stabilized output voltages required for supplying the load, and a boost stage 4, located upstream from the power stage 7, which allows to increase the voltage to a value in the range of 120 VDC to 373 VCC, whenever it is below such range.

Abstract: A resonance converter and a synchronous rectification driving method thereof are provided. The resonance converter includes a switch circuit having at least two first switches, a resonance circuit having a resonance frequency, a transformer, and a full-wave rectification circuit having two second switches each of which has a drain and a source and generates a channel resistance voltage when a current flows through the drain and the source. The synchronous rectification driving method includes steps as follow.

Abstract: A power supply device has a first node to which an input voltage is input, a second node, a third node from which an output voltage is output, a first switching circuit electrically connecting the first node and the second node and a resonance circuit electrically connecting the second node and the third node. The power supply device converts the input voltage into the output voltage through an intermediate voltage of the second node. A first timing circuit is operable to turn on and turn off the first switching circuit. When the intermediate voltage becomes equal to or larger than a first predetermined voltage, the first timing circuit turns on the first switching circuit after a first predetermined time period.

Abstract: A DC/DC converter includes: a boost converter that boosts an input voltage in accordance with a first control signal; an insulated converter that converts an output of the boost converter in accordance with a second control signal; a current sensor that detects an output current of the insulated converter; a first controller that generates the first control signal based on an error between the output current detected by the current sensor and a first threshold value; and a second controller that generates the second control signal based on an error between the output current detected by the current sensor and a second threshold value that is larger than the first threshold value.

Abstract: The present invention, according to a preferred embodiment, is directed to portable electronic devices which operate on exhaustible power sources, for example, batteries. The electronic devices of the present invention comprise at least one signal switch and a microchip in communication with the switch wherein the switch is only capable of transmitting a signal to the microchip that the switch has been activated or deactivated. The microchip is in communication with the exhaustible power source of the electronic device and controls (i) the power on/off function of the device, (ii) at least one other function of the device in response to activation and deactivation signals from the switch, and (iii) an automatic shut off function in response to the receipt of an activation signal from the switch.

Abstract: This invention relates to control techniques and controllers for resonant discontinuous forward power converters (RDFCs). We describe a controller for a resonant discontinuous forward converter (RDFC), said forward converter including a transformer with first and second matched polarity windings and a switch to switch dc power to said first winding of said transformer, said converter further having a dc output coupled to said second winding of said transformer, and wherein said controller has two modes, a first operational mode during which said switch is controlled to switch said dc power at a frequency which substantially coincides with a resonant frequency of operation of said RDFC such that said RDFC supplies power from said dc output, and a second, reduced power operational mode during which a drive to said switch is controlled to increase a proportion of time during which said switch is off.

Abstract: A simple zero current switch circuit includes a first coil set and a second coil set that are wound at a selected coil ratio and bridge electrically an energy storing inductor, an output diode and a conduction switch of a power-factor corrector. The leaking inductance of the first coil set generates a back electromotive force to make the conduction switch in a zero current switching condition. An energy conversion circuit is provided to store reverse energy according to the coil ratio of the second coil set and the first coil set and reclaims the energy to an output capacitor of the power-factor corrector while the output diode generates a reverse recovery condition. Thereby reverse recovery time of the output diode can be shortened.

Abstract: A quasi resonant type switching power supplying unit includes an overcurrent limiting circuit and an oscillation level comparison circuit. The overcurrent limiting circuit (i.e., a level determining circuit and a reference voltage generating circuit) receives a reverse electromotive voltage generated from an auxiliary winding which is electromagnetically connected with a primary winding when a MOSFET is in an OFF state, and produces a reference voltage stepwise based on the reverse electromotive voltage. The oscillation level comparison circuit receives a feedback voltage corresponding to electric power supplied to a load, and produces a control signal that switches the MOSFET into an OFF state when the feedback voltage exceeds the reference voltage.

Abstract: A method and an apparatus for switching performance are provided. The method includes: providing a performance adjustable circuit working at a specific threshold frequency; determining a working power supply of the performance adjustable circuit; when the working power supply is higher or lower than a specific threshold level range corresponding to the specific threshold, adjusting the performance adjustable circuit to work at another specific threshold frequency.

Abstract: A switching power source apparatus has a switching element being connected with a DC power source through a primary winding of a transformer in which parasitic capacitance exists between terminals of the switching element. A voltage V4 of free oscillation appears at a gate of the switching element after a flyback period due to the parasitic capacitance. Based on the free oscillation voltage, the switching power source apparatus detects timing synchronized with a period of the free oscillation, outputs a trigger signal V10 based on the detected timing, uses the trigger signal to estimate bottom timing when the free oscillation reaches a bottom level the second time, outputs an ON start signal V9 synchronized with the bottom timing, uses the ON start signal to output an ON control signal to turn on the switching element, and drives the switching element in response to the ON control signal.

Abstract: A method for driving a fluorescent lamp and an inverter circuit for performing the same are used to reduce an amount of electromagnetic interference (EMI) generated by a transformer and an instantaneous loading of a DC voltage source. The inverter circuit comprises a DC square wave voltage source, a bridge DC/AC converter, a transformer, a feedback control unit and a voltage control circuit wherein the voltage control circuit is coupled to the DC voltage source, the bridge DC/AC converter and the feedback control unit. The voltage control circuit is used to convert DC voltage provided by the DC voltage source into a two-level DC square wave, which in turn converts the two-level DC square wave into an AC quasi-sine wave to drive the fluorescent lamp through the bridge DC/AC converter and the transformer. The feedback control unit generates signals to control the voltage control circuit and the bridge DC/AC converter.

Abstract: A switching regulator, has first and second switching regulator units, and first and second PLL circuit units that are provided in the first and second switching regulator units respectively, input first and second control pulse signals (PIN1, PIN2) respectively, phases of which are shifted from each other, and control the first timing (T1) of performing non-conduction control on the first switching element (LMOS). The first and second control pulse signals each is controlled to have a frequency corresponding to a voltage-boosted level of the output terminal to maintain the output voltage at predetermined voltage.

Abstract: A method for driving a fluorescent lamp and an inverter circuit for performing the same are used to reduce an amount of electromagnetic interference (EMI) generated by a transformer and an instantaneous loading of a DC voltage source. The inverter circuit comprises a DC square wave voltage source, a bridge DC/AC converter, a transformer, a feedback control unit and a voltage control circuit wherein the voltage control circuit is coupled to the DC voltage source, the bridge DC/AC converter and the feedback control unit. The voltage control circuit is used to convert DC voltage provided by the DC voltage source into a two-level DC square wave, which in turn converts the two-level DC square wave into an AC quasi-sine wave to drive the fluorescent lamp through the bridge DC/AC converter and the transformer. The feedback control unit generates signals to control the voltage control circuit and the bridge DC/AC converter.

Abstract: A converter-controller includes a power device, coupled to the primary coil of a transformer, a resonant circuit, coupled to the primary coil and the power device, a voltage regulator, coupled to the resonant circuit, and a control logic, coupled to the voltage regulator. The converter-controller does not need a snubber circuit. Further, the transformer structure of the converter-controller does not need additional auxiliary windings around the transformer core. The described converter-controller makes it possible to use low voltage integrated circuits in high voltage applications.

Abstract: In a lighting apparatus for a discharge lamp, a mask signal against a re-arc voltage is correctly generated to detect a lamp voltage accurately in view of a support to high frequency lighting such that the detection of the lamp voltage is not affected by the re-arc voltage. The lighting apparatus for the discharge lamp comprises a DC-AC converter for receiving an input voltage from a DC power supply to convert the input voltage to an AC voltage; detecting means for detecting a lamp voltage associated with a discharge lamp or a lamp voltage and a lamp current; and a signal generator circuit for generating a mask signal for excluding a re-arc voltage, which occurs at the time the polarity is inverted, from items to be detected, in the event of a detection of the lamp voltage. The signal generator circuit detects the lamp voltage or lamp current or a voltage at an output stage of the DC-AC converter to correctly capture a polarity inversion timing to generate a mask signal against the re-arc voltage.

Abstract: The present invention provides a power supply circuit performing constant voltage control by switching frequency control and achieving minimization of a necessary control range of the switching frequency control and implementation of a configuration ready for a wide range. A switching power supply circuit includes a switching circuit, a switching driving unit, an insulating converter transformer, a primary side series resonance circuit, a secondary side series resonance circuit, a secondary side DC output voltage production unit, a constant voltage control circuit, and a composite coupling coefficient setting mechanism.

Abstract: This invention relates to new soft-switching techniques for minimizing switching losses and stress in power electronic circuits using inverter legs. By choosing the switching frequency with specific relationships with the resonant frequency of the power electronic circuits, the proposed switching technique enables the power electronic circuits to achieve soft switching under full load and short-circuit conditions at the defined frequencies for both capacitive and inductive loads. This technique can be applied to an electronic circuit with two switches connected in totem pole configuration between two dc voltage rails or commonly known as a power inverter leg or inverter arm. Examples of these circuits are class-D power converter, half-bridge power converters and full-bridge power converters or inverters. The proposed techniques allow inverter circuits with resistive, capacitive and inductive loads to achieve soft switching.

Abstract: The invention relates to an electronic circuit for igniting a high-pressure lamp. A resonant circuit 13 of the circuit is used to supply the ignition voltage for the high-pressure lamp. To enable an exact adjustment of the resonance frequency in the resonant circuit, it is proposed that the circuit also comprises converter 12 for generating an alternating voltage with which the resonant circuit 13 is excited and an oscillator 14, 16, 17 for driving the converter 12, the fundamental frequency of the output voltage of the oscillator being at least in proximity to an integral fraction of the resonance frequency of the resonant circuit 13. Finally, it is proposed that the circuit includes a feedback 17 from the resonant circuit 13 to the oscillator 14, 16, 17, whereby the fundamental frequency of the output voltage of the oscillator is so tuned that the resulting frequency of the output voltage of the oscillator corresponds substantially exactly to the integral fraction of the resonance frequency.

Abstract: A welding machine with a power source and an inverter. The inverter has at least one switching leg, made up of switches in series, and an output terminal. The power source has a circuit for controlling the switches by delivering an on-signal or and off-signal. The power source also has a transformer linked to a rectifier. The power source also has a circuit for detecting the voltage that the terminals of each switch of the inverter. A pilot circuit is also present for receiving control and voltage signals. The pilot circuit then sends a pilot circuit to each of the switches. The pilot signal corresponds to an on-command when the control signal corresponds to an on-signal and when the voltage between the power electrodes is very close to zero.

Abstract: A high voltage offset detection circuit registers the voltage at the midpoint of a switching half-bridge to determine when the midpoint voltage reaches a given value to avoid hard-switching in the half-bridge switches. The midpoint voltage of the switching half-bridge is applied through a buffer to a MOSFET that is current limited to produce a voltage that reflects the voltage of the midpoint of the switching half-bridge. The voltage produced by the MOSFET may be supplied to a comparator with a threshold input to obtain a signal that indicates when the switches of the switching half-bridge may be turned on to avoid hard-switching. The MOSFET may be selectively enabled to detect the voltage. The buffer operates to prevent voltages being applied to the MOSFET lower than a low side return voltage to prevent shorts in the IC between the low side supply voltage and low side return.

Abstract: Provided is a DC-DC converter which is capable of obtaining a stable output irrespective of the fluctuation of the power source voltage and ensuring the reliability of a device. The DC-DC converter configured such that a current of a primary coil of a boosting transformer supplied from a power source unit is intermittently caused to flow through the converter by a power MOS-FET and an ignition capacitor is charged with electricity through a rectifier diode using the voltage of a secondary coil of the boosting transformer boosted by the flyback voltage of a coil, includes a current detecting circuit for detecting a drain current of the power MOS-FET, and a control circuit for, when the drain current detected by the current detecting circuit exceeds a predetermined threshold, turning off the power MOS-FET for a fixed period of time, and then turning on the power MOS-FET again.

Abstract: In a DC/DC converter using an insulating transformer Tr having a center tap on the secondary side, an input choke coil L1 and an output choke coil L3 are integrated with the insulating transformer Tr, a primary coil (number of turns: 2N) and a secondary coil (number of turns: n+n) of the transformer, the input choke coil L1 (number of turns: 2N), and the output choke coil L3 (number of turns: n) are wound around a common core (magnetic core), and the coils are arranged in directions of canceling DC fluxes generated by the coils, so that the DC bias magnetization is considerably reduced.

Abstract: A contactless electrical energy transmission system includes a transformer having a primary winding that is coupled to a power source through a primary resonant circuit and a secondary winding that is coupled to a load through a secondary resonant circuit. The primary and secondary resonant circuits are inductively coupled to each other. A primary control circuit detects current changes through the primary resonant circuit to control the switching frequency of a controllable switching device for maintaining a substantially constant energy transfer between the primary winding and secondary winding in response to at least one of a power source voltage change and a load change. As a result, excessive circulating energy of the CEET system is minimized providing a tight regulation of the output voltage over the entire load and input voltage ranges without any feedback connection between the primary side and the secondary side.

Abstract: The present invention relates to an inductive contactless power transmitter having a primary side including a first inductor (LP) on the primary side and an oscillator for producing an alternating signal which is supplied to the inductor (LP) on the primary side, and having a secondary side which includes an inductor on the secondary side that can be coupled to the inductor (LP) on the primary side, a load (RL) which is variable in time, and a detection means (42) for determining a power demand of the load on the secondary side, the first oscillator being a voltage-controlled oscillator having a frequency that is adjustable in response to the power demand determined by the detection means (42).

Abstract: By using xylobiose or xylooligosaccharide containing xylobiose as a main ingredient in place of lactulose, there is provided a blood ammonia lowering agent, a therapeutic agent of hyperammonemia or a therapeutic agent of hepatic encephalopathy that need be adminstered in smaller doses and which have no concern over side effects. Lactulose conventionally used as such drugs has to be administered in high doses and involves a safety problem when administered to patients with galactosemia or diabetes mellitus. The drug of the invention which contains xylobiose as a main ingredient solves these problems.

Abstract: The present invention provides a self-driving circuit of a low voltage, large current, and high power density DC/DC converter. The converter comprises a transformer, power MOS transistors (S), output rectification portion (SRb 1, SR2), filter portion and demagnetizing portion. The first configuration of the self-driving circuit consists of Da, Ra, Ca, Qa for self-driving SR2; and the second configuration consists of Da, Ra, Sa, a delay driving circuit and an isolation differential circuit, for self-driving SR2. The self-driving circuit of the present invention may reduce the cross-conductive loss, and increase the converting efficiency.

Abstract: A DC power converter enclosing a regulated AC power supply within the overall design topology. The power transfer function incorporates a process wherein a portion of the negative AC signal, generated across the input winding of a power transformer, is intercepted by a power switch transitional state. The volt-second product of the intercepted AC signal is reflected into the DC input line voltage as an additive element allowing a resonant inductor to absorb the sum of both components. Thus peak voltage transferred to a resonant capacitor is two times the sum of voltage absorbed by the resonant inductor as opposed to simply doubling the DC input line voltage. Voltage across the resonant capacitor remains constant for variations in DC input line voltage within the limits of the input voltage regulating band. This is due to an inverse relationship between the DC input line voltage and voltage yielded by the negative AC signal, at point of interception by the timing pulse.

Abstract: A fluorescent lamp lighting apparatus in accordance with the present invention has first switching means (M1) driven by a high-voltage-side pulse signal input from a drive-signal generation circuit and second switching means (M2) driven by a low-voltage-side pulse signal input from the drive-signal generation circuit, wherein the first switching means (M1) is connected in series with the second switching means (M2), and a first capacity (C5) and an inductance element (L1) and the above-mentioned second switching means (M2) are provided between the high-voltage-side terminals of a pair of filament electrodes of a light-emitting tube (4), whereby a constant luminous flux can be maintained immediately after lighting.