Abstract: A first charge/discharge element is connected in parallel to a coil porion of the primary coil of a converter transformer. A second charge/discharge element is connected in parallel to a coil portion of the primary coil. The first charge/discharge element is charged with the energy stored in the primary coil when the first switching element turns off. A smoothing capacitor is charged with the charge energy when the second switching element turns off. The second charge/discharge element is charged with the energy stored in the primary coil when the second switching element turns off. The smoothing capacitor is charged with the charge energy when the first switching element turns off.

Abstract: A controller for controlling at least two power circuits comprises a pulse generator and a selector. The pulse generator generates a first pulse signal which is coupled to a first power circuit of the at least two power circuits for initiating the operation of the first power circuit. The first power circuit then outputs a second pulse signal to a second power circuit of the at least two power circuits to initiate the operation of the second power circuit. The selector generates a reference signal which is coupled to each of the at least two power circuits for indicating a number of power circuits controlled. The controller is used to control energy supplying to an electrical circuit comprising multiple inverters and is more particularly to provide phase shifts to the electrical circuit. Usually, the electrical circuit is applied to display devices, such as liquid crystal display monitors, liquid crystal display computers and liquid crystal display televisions.

Abstract: A multiple-phase power converter comprises a non-isolated, double-ended transformer having a plurality of windings, a high-side switch portion, a low-side switch portion, an output portion, and a controller. The high-side switch portion includes a first power switch connecting an input voltage source (VIN) to a virtual phase node through a first winding of the plurality of windings and a second power switch connecting the input voltage source to the virtual phase node through a second winding of the plurality of windings. The first and second windings are arranged with opposite polarity. The low-side switch portion includes a third power switch connecting the virtual phase node to ground through a third winding of the plurality of windings and a fourth power switch connecting the virtual phase node to ground through a fourth winding of the plurality of windings. The third and fourth windings are arranged with opposite polarity.

Abstract: A transformer has a primary winding and a secondary winding. A center tap of the primary winding is connected with one end of a d.c. power supply. Both ends of the primary winding are connected to the drains of transistors (Q1) and (Q2) that constitute switching elements, respectively. Also, the sources of the transistors (Q1) and (Q2) are connected to the other ends of the d.c. power supply. The gates of the transistors (Q1) and (Q2) are connected to one ends of gate resistors (R1) and (R2), respectively. The other ends of the gate resistors (R1) and (R2) are connected to a control circuit, and the resistance of the gate resistor (R2) is larger than the resistance of the gate resistor (R1).

Abstract: AC to DC inverters that are formed from electronic switches, such as MOSFETs, that are controlled by gating pulses obtained from comparators. The comparators compare a varying signal against two closely spaced reference voltages so as to provide gating pulses with delays needed to prevent shoot-through in the electronic switches.

Abstract: A voltage power supply circuit is provided that uses the voltage output of an oscillator to provide a high voltage DC output to drive a liquid crystal display device. A controller IC opens and closes an FET to allow the EMF of an inductor to generate a DC voltage that exceeds the battery voltage source for the liquid crystal display device. Accordingly, the oscillator circuit that drives a back light display for a liquid crystal device is simultaneously used to generate the high voltage DC source for the liquid crystal display device.

Abstract: An efficient power conversion circuit for driving a fluorescent lamp uses a minimum pulse generator circuit to control the minimum on-time of a time modulated signal to increase the dimming range of the fluorescent lamp operating over a wide range of temperature and supply voltage. A minimum number of lamp current cycles with respective amplitudes above a preset threshold is typically required to avoid flickering or shimmering during minimum brightness. The minimum pulse generator circuit counts the lamp current cycles and adjusts the on-time accordingly to guarantee the minimum number of cycles with respective amplitudes above a preset threshold under all operating conditions.

Abstract: A high input-voltage push-pull forward voltage regulator module (VRM) has high efficiency and fast transient response. The VRM has a primary side wherein two switches and two primary transformer windings are alternately connected in a loop. A capacitor is connected between any of two interleaved terminations. The remaining two terminations are connected to input and ground respectively. The two primary transformer windings have the same number of turns. A number of secondary sides may be used such as, for example, a half wave rectifier or a center tapped secondary. The high input-voltage push-pull forward VRM has high efficiency and fast transient-response with reduced filter capacitance and inductance. Its magnetic components can be easily integrated. As a result, very high power density can be achieved. The device die size needed to achieve the required efficiency is reduced. And control is simple. Therefore, this topology is very cost effective.

Abstract: AC to DC inverters that are formed from electronic switches, such as MOSFETs, that are controlled by gating pulses obtained from comparators. The comparators compare a varying signal against two closely spaced reference voltages so as to provide gating pulses with delays needed to prevent shoot-through in the electronic switches.

Abstract: The invention relates to the compensation of dead time effect in electronic appliances such as inverters or converters having one or more legs with two complementary switches. The invented method mainly includes following steps providing an initial pulse width modulated (PWM) reference, providing a bias current and detecting the bias current crossing points, providing a dead time compensation signal which is adjusted responsive to the crossing points, and adding the dead time compensation signal to the PWM reference. Hence an adaptive compensation is accomplished independent of types of switching elements and load conditions. A high reliable circuit with low cost is further included as a preferred embodiment of bias current crossing points detection.

Abstract: A high power motor drive converter comprises: a three level neutral point clamped (NPC) output power conversion stage including switches for supplying power to an AC drive motor; a split series connected DC capacitor bank coupled in parallel with the NPC output power conversion stage; and a controller for selecting switch positions for controlling the NPC output power conversion stage and compensating for a neutral point voltage imbalance of the DC capacitor bank by adjusting amplitudes of carrier voltages according to an amount of voltage imbalance in the split series connected DC capacitor bank.

Abstract: A switching power supply unit includes first and second switching circuits which alternately turn first and second switching elements on and off with an intermediate period in which both are turned off, and energy is stored in a primary winding of a transformer during an ON period of the first switching element and the energy is discharged from a secondary winding of the transformer during an OFF period of the first switching element. A control circuit includes an OFF period extending circuit connected to a control terminal of the first switching element, such that a transistor remains turned on for a desired period even after the energy has been discharged from the secondary winding, extending the OFF period of the first switching element for the desired period. In a light load operation, a phototransistor in the second control circuit is turned on so that the ON period of the second switching element will be shorter than the time required to discharge the energy from the secondary winding.

Abstract: The present invention relates to a converter comprising at least one converter module presenting at least one electricity feed terminal coupled to an electricity generator and to an electricity feed line such as a bus and including at least one series switch and at least one parallel switch, the series switch being connected in series between the electricity feed terminal and a first inductor, itself in series with an electricity source, the first series switch and the first inductor forming a series branch, and the parallel switch being connected in parallel between said series branch and ground, said switches of said module being controlled in phase opposition by a control circuit presenting a first control state in which said switches are operated in a first or “voltage-lowering” mode of operation in which an electrical current flows from the electricity generator to the electricity feed line, and a second control state in which said switches are operated in a second or “voltage-raising&r

Abstract: An efficient power conversion circuit for driving a fluorescent lamp uses a minimum pulse generator circuit to control the minimum on-time of a time modulated signal to increase the dimming range of the fluorescent lamp operating over a wide range of temperature and supply voltage. A minimum number of lamp current cycles with respective amplitudes above a preset threshold is typically required to avoid flickering or shimmering during minimum brightness. The minimum pulse generator circuit counts the lamp current cycles and adjusts the on-time accordingly to guarantee the minimum number of cycles with respective amplitudes above a preset threshold under all operating conditions.

Abstract: Driving a quadrupole mass spectrometer includes obtaining an air core transformer with a primary and a secondary, matching the secondary to the mass spectrometer, and driving the primary based on first and second voltage levels. Driving of the primary is via an isolating stage that minimizes low level drive signal coupling.

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: An efficient power conversion circuit for driving a fluorescent lamp uses a minimum pulse generator circuit to control the minimum on-time of a time modulated signal to increase the dimming range of the fluorescent lamp operating over a wide range of temperature and supply voltage. A minimum number of lamp current cycles with respective amplitudes above a preset threshold is typically required to avoid flickering or shimmering during minimum brightness. The minimum pulse generator circuit counts the lamp current cycles and adjusts the on-time accordingly to guarantee the minimum number of cycles with respective amplitudes above a preset threshold under all operating conditions.

Abstract: A three-level DC-to-DC converter is provided having zero-voltage and zero-current switching (ZVZCS). A flying capacitor is provided on the primary side of the converter to achieve zero voltage switching (ZVS). In addition, during freewheeling (i.e., when no power is being transferred from the primary side to the secondary side), an auxiliary power source is provided to eliminate the circulating energy and to achieve zero current switching (ZCS) for the commutation switches.

Abstract: A current driver circuit for writing data to a hard disk receives an input signal and generates a current for driving a load. A drive circuit supplies the load with a current. A damping circuit connected to the drive circuit restricts the current supplied to the load in accordance with a pulse signal. A damping control signal connected to the damping circuit generates the pulse signal in response to the input signal and provides the pulse signal to the damping circuit.

Abstract: An inverter circuit for supplying power to a lamp. The circuit comprises a DC voltage supply source. The circuit also comprises a transformer having a primary and a secondary winding. The secondary winding is coupled to the lamp and the primary winding is coupled to the DC supply source. The circuit also comprises a pair of inductors coupled in series to opposite ends of the primary winding. A capacitor couples the inductors together. The circuit is configured such that the pair of inductors, in conjunction with the capacitor, alternately resonate to provide an AC current supply source to the lamp. The circuit further comprises a pair of switches which alternately turn “on” and “off”, thereby causing the pair of inductors to alternately resonate. A control driver is coupled to the pair of switches and is configured to alternately turn on and off the pair of switches. Advantageously, the control driver comprises a PWM control driver.

Abstract: All efficient power conversion circuit for driving a fluorescent lamp uses a minimum pulse generator circuit to control the minimum on-time of a time modulated signal to increase the dimming range of the fluorescent lamp operating over a wide range of temperature and supply voltage. A minimum number of lamp current cycles with respective amplitudes above a preset threshold is typically required to avoid flickering or shimmering during minimum brightness. The minimum pulse generator circuit counts the lamp current cycles and adjusts the on-time accordingly to guarantee the minimum number of cycles with respective amplitudes above a preset threshold under all operating conditions.

Abstract: The switching converters of a power supply device are adapted to equally share the power output of the device. The power supply device 1 comprises a plurality of resonance type switching converters 4, 5 connected in parallel relative to a load, frequency control circuits 6, 7 for controlling respectively the switching frequencies of the switching converters 4, 5, a feedback circuit 8 for feeding back the voltage applied to the load and a resonance current balance circuit 9 for detecting the wave heights of the resonance currents flowing respectively through the switching converters 4, 5 and comparing them. The frequency control circuits 6, 7 control the switching frequencies so as to make the voltage applied to the load show a predetermined voltage value and also make the wave heights of the resonance currents equal to each other.

Abstract: A push-pull converter, coupled through an isolation transformer to a crowbar circuit for controlling an isolated output voltage across an output capacitor, has a compact circuit arrangement with a minimal number of components. The switching devices of the push-pull converter have integrated, ultra-fast anti-parallel diodes. The crowbar circuit is a voltage-controlled bi-directional switch coupled between the transformer and the output capacitor. The converter is controlled in an output-voltage-on mode by turning on and off the first switching device, and in an output-voltage-off mode by applying a gating signal to the second switching device sufficient to both activate the crowbar circuit and discharge the output capacitor for very fast isolated output voltage turn-off. In addition, a primary-side circuit comprising a switch and a resistance can be used to avoid excessive residual output voltage build-up.

Abstract: A power supply apparatus is disclosed, that comprises a DC power supply, a plurality of switch means for converting the output voltage of the DC power supply into an AC voltage, a transformer tap-connected to the DC power supply, a capacitor for charging/discharging an output current of the DC power supply, and a choke coil for suppressing the fluctuation of the output current of the DC power supply or the fluctuation of the current value of a discharge current of the capacitor.

Abstract: In a power supply apparatus which supplies a high-tension alternating voltage to a load, field-effect transistors (N-MOS) are disposed between both ends of a converter transformer having a center tap and the ground respectively, and a field-effect transistor (P-MOS) is disposed between the center tap and a power supply. In an ordinary operation, a transistor connected to the center tap is being on and transistors at the both ends of the converter transformer are alternately switched at the same frequency by a converter transformer driving circuit, thereby generating the high-tension alternating voltage on the side of a secondary winding of the converter transformer. When the generation of the high-tension alternating voltage is stopped, the driving circuit is controlled to cause the transistor connected to the center tap to be off and cause the transistors at the both ends of the converter transformer to be on, thereby preventing an unstable output voltage generated when output oscillation is stopped.

Abstract: A piezoelectric transformer inverter can be driven in wide ranges of input voltages and output currents so that a wide range of dimming can be achieved. Furthermore, the piezoelectric transformer inverter can maintain high efficiency in the overall driven ranges thereof so as to yield stable luminance.

Abstract: A power supply for a quadrupole mass spectrometer which operates using an RF signal. The RF signal is controllable via a feedback loop. The feedback loop is from the output, through a comparator, and compared to a digital signal. An air core transformer is used to minimize the weight. The air core transformer is driven via two out of phase sawtooth signals which drive opposite ends of the transformer.

Abstract: A DC to DC converter that uses three switching devices and processes power in such a way that it can operate very efficiently. The converter only processes that portion of the input power that is required to provide regulation. In addition, by judiciously selecting magnetic components and turns ratios, the converter can be optimized for narrow input voltage ranges or for wide input voltage ranges. The converter operates in such a way that it can add or subtract energy on the primary side of the converter to achieve regulation.

Abstract: A device selectively supplying a high voltage and a ground level voltage to electrodes of an electroluminescent display panel. The voltage supply device includes a first and a second transistor connected in series, and outputs the high voltage upon turning on the first switching transistor and the ground level voltage upon turning on the second switching transistor. The device includes a circuit for selecting either an operation mode under which the device is normally operated with the high voltage or a test mode under which the device is tested under a low test voltage. The mode selection is performed by an external signal supplied to the device. Under the test mode, the switching transistors are turned on with a low gate voltage by operation of a circuit built in the device. Accordingly, the voltage supply device normally operated under the high voltage is easily tested under the low test voltage.

Abstract: A circuit is described for balancing a power supply having a positive bus with a positive voltage, and a negative bus with a negative voltage. The circuit includes a transformer having a primary winding and a secondary winding. Switching circuitry alternately connects the positive bus and the negative bus to the primary winding of the transformer thereby generating a secondary voltage of opposite polarity on the secondary winding of the transformer. Recycling circuitry is also included which is coupled to the secondary winding of the transformer and the positive and negative buses. When the secondary voltage is greater than the positive voltage, power is transferred from the negative bus to the positive bus via the transformer and the recycling circuit. When the secondary voltage is less than the negative voltage, power is transferred from the positive bus to the negative bus via the transformer and the recycling circuit.

Abstract: A resonant switching power supply has a zero voltage and zero current switch feature which can be operated in a half-bridge or a full-bridge scheme. This enables power consumption to be reduced and electromagnetic radiation to be minimized, and provides for low cost and convenient manufacture, in mass production. The power supply is not influenced by parasitic capacitance and leak inductance. The resonant switching power supply is disclosed in several different embodiments.

Abstract: A DC/DC converter comprising a buck stage that includes a buck switch, a push-pull stage that includes push-pull switches, and a controller to control the switching phases of the buck and push-pull switches. The turn-on phases of these buck and push-pull switches are automatically and continuously adjusted to an optimal value at each occurrence of a synchronization pulse produced at a fixed frequency by an autosynchronization circuit.

Abstract: A piezoelectric transformer inverter includes an inverter unit and a step-down chopper unit. The inverter unit includes a ceramic piezoelectric transformer whose secondary terminal is to be connected to a fluorescent tube, a drive unit which is connected to a primary terminal of the ceramic piezoelectric transformer, and an inverter control circuit for controlling luminance of the fluorescent tube to a desired value. The step-down chopper unit includes a switching device which is disposed on the side where the voltage of the inverter unit is input, a free wheeling device connected between the switching device and a reference potential, and a PWM feedback control circuit for providing a feedback control to maintain an average voltage of the rectangular-wave voltage of the switching device constant.

Abstract: An asymmetrical power converter and method of operation thereof. In one embodiment, the asymmetrical power converter includes (1) an isolation transformer having series-coupled first and second primary windings providing differing turns ratios therefrom, (2) a first power switch and a first input capacitor series-coupled to the first primary winding to form a first circulation path between the isolation transformer and an input of the asymmetrical power converter and (3) a second power switch and a second input capacitor series-coupled to the second primary winding to form a second circulation path between the isolation transformer and the input.

Abstract: A switching power supply device has a configuration in which a series combination of a first switching circuit and an input power source is connected in series with a series combination of a primary winding of a transformer and an inductor, a series combination of a second switching circuit and a capacitor is connected in parallel to the series combination of the primary winding of the transformer and the inductor, and the secondary winding of the transformer is provided with a rectifying smoothing circuit including a rectifying element. The first switching circuit is made up of a parallel connection circuit including a first switching element, a first diode, and a first capacitor. The second switching circuit is made up of a parallel connection circuit including a second switching element, a second diode, and a second capacitor.

Abstract: In a switching power source, by alternately turning on first and second MOS transistors, a switching current flows to a primary winding of a transformer, and an alternate current is transferred to a secondary side. The alternate voltage caused in a secondary winding is full-wave rectified by first and second diodes. Resonance elements (capacitor and coil) are connected to a tertiary winding coupled to an isolation transfer, thereby enabling the primary side to be set into a resonated state and to be set to a current resonance type switching power source. Since a leakage inductance of the transformer is not set to a resonance element, an interval between the windings of the isolation transformer can be closely coupled. Since a resonance current is not directly turned on/off, a peak value of the primary current is decreased and switching loss and loss due to an on-resistance can be decreased. The efficiency of a current resonance type switching power source is thus improved.

Abstract: An input-side rectifier of a DC power supply apparatus receives and rectifies an AC voltage selected from first and second groups of AC voltages. The AC voltages in the second group are lower than those of the first group. A voltage boosting/lowering converter boosts or lowers the output voltage of the input-side rectifier to a voltage having a predetermined value. An inverter converts the output voltage of the voltage boosting/lowering converter to a high-frequency voltage. A voltage transformer transforms the high-frequency voltage from the inverter. An output-side rectifier rectifies the transformed high-frequency voltage from the transformer.

Abstract: A resonance type power converter unit has, in an inverter circuit in which voltage driven type semiconductor devices each having the function not to prevent a backward current are connected in series, the respective voltage driven devices are associated with capacitors which are charged or discharged with currents flowing through the devices and voltage detectors for detecting voltages of the capacitors, and drive circuits for turning on and off the voltage driven devices in accordance with outputs of the voltage detectors. With the resonance type power converter unit, stable resonance operation synchronous with a high-frequency load current can be warranted.

Abstract: A power terminal is connected to a DC power source. A differential amplifier has primary and secondary input terminals and an output terminal, and a device applies a reference voltage to the secondary input terminal of the differential amplifier. A phase inverter has an input terminal connected to the output terminal of the differential amplifier and has primary and secondary output terminals that output two output signals of opposite phase. A push-pull drive circuit has primary and secondary input terminals connected to the primary and secondary output terminals of the phase inverter, and has primary and secondary output terminals connected to a switching element that alternately turns on and off by being driven by the two output signals of opposite phase that are provided from the output terminals of the phase inverter.

Abstract: Boost Mode Regulator techniques are used to provide regulated a.c. or d.c. output from a.c. or d.c. sources. One embodiment involves regulation of the output of an a.c. source to provide a regulated d.c. voltage. The source inductance becomes part of the boost mode circuit, thus avoiding the losses associated with the addition of external inductors. When a three-phase alternator is the power source, the circuit comprises a six diode, three-phase rectifier bridge, three FET transistors and a decoupling capacitor. The invention involves shorting the output of the power source to allow storage of energy within the source inductance. During this time, the decoupling capacitor supports the load. When the short is removed, the energy stored in the inductances is delivered to the load. Because the circuit uses the integral magnetics of the source to provide the step-up function, the efficiency of the design can be quite high.

Abstract: A power supply circuit for powering a load circuit comprises a load circuit and includes a converter circuit for inducing current in the load circuit. The converter circuit comprises first and second converter switches serially connected in the foregoing order between a bus conductor at a d.c. voltage and a reference conductor, and connected together at a common node through which the load current flows. The first and second converter switches each comprise respective interconnected control nodes and references connected together at the common node. The voltage between a control node and associated reference node determines the conduction state of the associated switch. A first node is coupled to the bus conductor, and a second node is coupled to the reference conductor. A bridge network is connected between the first and second nodes and has first and second input nodes on which respective first and second input signals are applied.

Abstract: A control device for a fluorescent lamp comprises two independent circuits based on a power transistor and a switching control circuit, series-connected between a high voltage and the ground. The power transistor has a diode that is reverse mounted between its two electrodes. The switching control circuit comprises a circuit for the detection of a voltage at the terminals of the diode greater than a voltage reference value and a circuit for the detection of the integral of the current flowing in the transistor that is greater than a current reference value corresponding to the power of the lamp.

Abstract: A ballast circuit for a gas discharge lamp comprises a resonant load circuit incorporating the gas discharge lamp and including a resonant inductance and a resonant capacitance. A d.c.-to-a.c. converter circuit induces an a.c. current in the resonant load circuit. The converter circuit comprises first and second converter switches serially connected in the foregoing order between a bus conductor at a d.c. voltage and a reference conductor, and being connected together at a common node through which the a.c. load current flows. The first and second converter switches comprise respective interconnected control nodes respective reference nodes interconnected together at a common node. The voltage between each control node and associated reference node determining the conduction state of the associated switch. A voltage-limited energy source is connected between first and second nodes.

Abstract: This push-pull switching power supply outperforms its counterparts. Each switch has twice the voltage ratings. However, only two main switches have current ratings as all four switches of the full-bridge power supply. That is only one half the current ratings of both switches of the half-bridge power supply. The input voltage is applied to a center tap of transformer's primary winding. The main switches are coupled thereacross for alternately applying the primary current to ground. Two diodes apply the leakage current of the transformer to a single capacitor. One or two auxiliary switches apply the primary current to the capacitor, whereby the leakage energy stored therein is immediately returned to the transformer. The auxiliary switches operate only a mere fraction of the time and thus their peak rather than continuous current ratings matter. The efficiency is significantly increased as a passive snubber network is eliminated and a reverse energy flow is prevented.

Abstract: The present invention is a DC to AC switching converter that does not require a dead zone. The output node of the classical switching pair is separated into two output nodes which eliminates the current path that made the dead zone necessary. Each of the switches are connected between +Edc and -Edc in a complimentary fashion. By eliminating the direct connection between the two switches, both switches can be operating simultaneously without any danger of failure. Both switch outputs pass through a current sensing feedback device and an output coil. The outputs of each coil are connected to the output of the switching converter having a filter capacitor connected to ground. This arrangement provides switching bias current during the zero current crossover point thereby eliminating the ringing and oscillation distortion that occurs in the dead zone. The desired output voltage waveform is a result of the summation of the two switch outputs after the high speed component has been removed through filtering.

Abstract: Disclosed is a ballast circuit for a gas discharge lamp comprising a resonant load circuit incorporating the gas discharge lamp, a resonant inductance, and a resonant capacitance. A d.c.-to-a.c. converter circuit induces an a.c. current in the load circuit, and comprises first and second converter switches serially connected in the foregoing order between a bus conductor at a d.c. voltage and a reference conductor. The switches are connected together at a common node through which the a.c. load current flows. The switches each have a control node and a reference node, the voltage between such nodes determining the conduction state of the associated switch. The respective control nodes of the switches are interconnected, and the respective reference nodes of the switches are connected together at the common node.

Abstract: Herein disclosed are a method and an apparatus for supplying an electrical energy to a pair of discharge electrodes spaced apart from each other to cause an electric discharge in a gap between the discharge electrodes. There are firstly provided an alternating voltage generator for generating, as the electrical energy, an alternating voltage having a frequency, and a capacitor connected to the discharge electrodes in series. The alternating voltage generator has a series resonant frequency. The alternating voltage of the alternating voltage generator is applied to the discharge electrodes through the capacitor. The frequency of the alternating voltage is set approximately to the series resonant frequency of the alternating voltage generator to cause a dielectric breakdown in and allow an electric discharge current to flow through the gap between the discharge electrodes.

Abstract: Constant-current regulators are required, for example, in systems for airfield lighting and have units for nominal-value presetting and actual-value detection as well as for actual value/nominal value comparison. According to the present invention, a constant-current regulator having a step-up transformer is designed in such a manner that the primary of the step-up transformer is assigned a unit for selection of a basic voltage, and in such a manner that a switch-mode regulator module supplies a power which is applied to the basic voltage.

Abstract: An inverter resistance welding control or power supply apparatus includes a clock generator which generates a clock signal defining a switching cycle of an inverter in a resistance welding machine, a device for preselecting a predetermined reference value corresponding to a desired current peak, a current sensor for detecting primary or secondary current of the welding machine, and an inverter control for controlling the inverter on a switching cycle-by-cycle basis. Specifically, the apparatus turns on the inverter in response to a leading edge of the clock signal, and turns the inverter off either when the current detected signal has reached the reference value or when the clock signal has reached a trailing edge. The control apparatus further includes a magnitude evaluator for measuring a magnitude of the current from the detected signal, which magnitude is expressed in root mean square, arithmetic mean or averaged peak value.

Abstract: A VHF inverter including an inverter circuit (100) for providing an inverter output; a constant magnitude, variable phase impedance transforming circuit (54, 154) responsive the inverter; and a load circuit (55, 155) responsive to the impedance transforming circuit.