Abstract: A device runs a precheck of an inductive load for an overload prior to swhing on to supply mains. For this purpose, following switching-on for a load precheck, initially a phase limited voltage signal is applied to the load, whereby the voltage signal duration gradually increases. With the start of each application of voltage, the active current is measured in a narrow time window. If it does not exceed a predetermined active current limit at an application of a specific effective voltage, the load is switched to the mains. Otherwise, the switch-on process is cut off. This switching-on process avoids a high taxing of the mains in the event of a short circuit or an overload. The active current window begins with the application of voltage to the load. At a different time than this time window, a further measurement window is provided for the reactive current, whereby this measurement window begins with the zero crossing of the alternating voltage.

Abstract: Heating pads using positive temperature coefficient (PTC) resistance material are subject to fire risk if one of the conductor wires between which the PTC material extends should break and produce an electric arc. Protection by fuse and a fuse-blowing circuit responsive to fire detection must allow for an immense inrush of current when the cold pad is turned on. A heat setting control using a microprocessor can reduce the fuse rating by chopping the a.c. heating current for a short start-up period following with full-on feed until the heat setting is reached. The presence of a microprocessor allows response to a safety circuit that detects a break in a heater feed or return conductor before much excess heat develops, so that the microprocessor can turn off the heater switch. That response is so quick that it can be confirmed by repeated detection after very short pauses before the heater switch (a triac) is turned off.

Abstract: Heating pads using positive temperature coefficient (PTC) resistance material are subject to fire risk if one of the conductor wires between which the PTC material extends should break and produce an electric arc. Protection by fuse and a fuse-blowing circuit responsive to fire detection must allow for an immense inrush of current when the cold pad is turned on. A heat setting control using a microprocessor can reduce the fuse rating by chopping the a.c. heating current for a short start-up period following with full-on feed until the heat setting is reached. The presence of a microprocessor allows response to a safety circuit that detects a break in a heater feed or return conductor before much excess heat develops, so that the microprocessor can turn off the heater switch. That response is so quick that it can be confirmed by repeated detection after very short pauses before the heater switch (a triac) is turned off.

Abstract: A circuit for operating relay contacts is based upon the utilization of an AC line zero voltage to provide a relay contact closure. The circuit is inexpensive and draws extremely low current levels. The circuit involves a latching arrangement of gates responsive to a zero crossing detector and a Delay Time output from a sensor. The gating circuits function in a latching arrangement which has an adjustable output to energize a relay and in turn provide for the closing of contacts which occurs substantially at zero voltage.

Abstract: A temperature control circuit is disclosed utilizing automatically either the electric heating (or cooling) element or a separate sensor to measure the instantaneous temperature of the thermal load device. Either a pulsating dc or an ac electric power source may be used with the temperature sensing occurring at near-zero points of the source voltage waveform. The sensor forms one element of a Wheatstone bridge which when unbalanced by a value lower than a chosen reference value, causes a monostable oscillator to flip for at least several cycles of the source power. This turns on a power SCR to feed electric current to the thermal load to increase its temperature (and resistance) until the bridge is again balanced to reverse the state of the monostable oscillator and turn off the SCR. A simple, reliable two step, user friendly calibration circuit is provided for the temperature selecting component.

Abstract: The current resonant converter according comprises a voltage converting transformer having a primary winding and a secondary winding, a switching circuit, disposed on the primary side of the transformer, for turning on and off a current supplied from an DC power to the transformer, a resonant circuit disposed adjacent to the transformer, a rectifying and smoothing circuit, disposed on the secondary side of the transformer, for supplying an output to a load, and a control circuit for controlling a switching frequency of the switching circuit, whereby the current resonant converter is operated in two modes, consisting of a first mode for prohibiting a DC current component from flowing in the primary winding and a second mode for allowing the DC current component to flow in the primary winding.

Abstract: A compact, high frequency, zero voltage switching quasi-resonant converter with a multi-resonant, bi-polar switch includes a resonant switch (S), a first diode (D.sub.p) in parallel with the switch (S), a second diode (D.sub.s)in series with the switch (S), first (C.sub.r1) and second (C.sub.r2) resonant capacitors and a resonant inductor (L.sub.r). The first resonant capacitor (C.sub.r1) is operatively connected to the resonant switch (S) such that any voltage change across the first resonant capacitor (C.sub.r1) necessitates a corresponding voltage change across the resonant switch (S). The second resonant capacitor (C.sub.r2)is operatively connected to the second diode (D.sub.s) such that any voltage change across the second resonant capacitor (C.sub.r2) necessitates a corresponding voltage change across the second diode (D.sub.p). The resonant inductor (L.sub.r) is operatively connected in series with the resonant switch (S) such that any current change through the resonant inductor (L.sub.

Abstract: A circuit array, adapted to be coupled to a load and a source of a main AC voltage, for reverse phase angle control whereby a current flow in the load is limited to a defined phase angle (.alpha.) of the main AC voltage, comprising the following components for sequential control of the reverse phase angle control: a switching element, connected to the load and coupled to the source of the main AC voltage, for actuating the current flow in the load; a time determining component; and an integrated circuit.

Abstract: A light dimmer with semiconductor power devices coupled between an alternating current supply and a lamp load, in the course of varying average power supplied to the lamp load, transitions the power devices under load between one and the other of substantially conductive and non-conductive conditions, increasing the duration of the transition by the power device itself from the minimum possible duration to reduce generated EMI. Undesirable effects of the high current demands of cold lamp filaments are reduced by initially increasing the conductive portion of half-cycles, relative to the proportion required to produce the desired amount of average power, while avoiding transitions at phase angles that would produce excessive losses. A transition shape may be employed in this mode and in normal operation that maximizes audible lamp noise suppression for a given level of thermal losses.

Abstract: A heater control apparatus for use with a plurality of printers each having a heater, comprises a detection part for detecting occurrence of zero crossing of a voltage signal supplied from a power supply and for supplying a zero cross signal each time the zero crossing is detected, a signal part for detecting an ON state of a request signal, the request signal being turned ON when a heater of any of the plurality of printers is currently turned ON, a first control part for determining a delay time in accordance with a predetermined device number setting value such that a timing with which a heat-on signal is supplied to a heater of a subject printer lags by the determined delay time behind a timing with which the zero cross signal is supplied by the detection part, and a second control part for supplying a heat-on signal to the heater of the subject heater at a timing defined by the determined delay time only when the request signal is turned OFF, thereby preventing two or more heaters from being turned ON si

Abstract: An improved forward converter switching at zero-current incorporates a mechanism for selectively regulating the amount of forward energy which is delivered to a load during each converter operating cycle. Energy is transferred from a voltage source toward a load in discrete packets via a small effective inductance (specifically the small effective leakage inductance of a transformer) and a capacitor, the combination of which define a characteristic time scale for the rise and fall of current such that a switching device connected in series with the voltage source can be cycled on and off at zero-current. The capacitor is connected to the load via a second inductor.

Abstract: A light dimmer, especially useful for entertainment lighting, provides a high degree of stability in dimmer performance by employing a high level of analog negative feedback and correcting for the undesirable effects on dimmer "curve" by precompensating the input value while it is digital. A lighting control system distributes both the alternating current supply and control signals representing desired adjustments to fixture intensity via a housing common to multiple enclosures. Each enclosure contains at least one dimmer and mechanically engages the housing, from which it obtains a power input via power contacts and a control signal via an electrically isolated coupling comprising an effective source on the housing and detector on the enclosure.

Abstract: A control device and system for an appliance and methods of making the same are provided, the control device having a control unit to energize the coil of a relay with a power source at substantially a desired lead point on the voltage wave cycle thereof so as to tend to cause the contacts of the relay to subsequently close substantially at a certain point on the voltage wave cycle each time a load is to be interconnected to the power source whereby a lag time period exists between the desired lead point and a certain point, the control unit having a sensing unit to sense the lag time by detecting when the coil current of the relay coil decreases momentarily by the contacts initially closing during that particular cycle of operation of the control device, the control unit having a unit to automatically adjust the desired lead point should the sensed lag time on a certain previous cycle of operation not cause the contacts to close substantially at the certain point in order to tend to cause the contacts to clo

Abstract: A solid state circuit interruption arrangement monitors a current path to provide protection to both a load and a solid state switch. The arrangement includes an energy absorber for absorbing energy from the current path in response to the solid state switch interrupting the current path, and a control circuit for periodically generating the interrupt signal to interrupt the current path for prescribed intervals and to control the current supplied to the load between a maximum current level and a minimum current level.

Abstract: A microwave oven having a fan motor rotation control function comprising an absolute humidity sensor for sensing the humidity inside the microwave oven, a fan motor for discharging water vapor inside the microwave oven externally, a microprocessor and a keyboard. The improved microwave oven further comprises a phototriac connected between said fan motor and a supplying line of AC power source for controlling AC power supplied to the fan motor in accordance with a plurality of control signals from the microprocessor and a zero crossing signal generating circuit for detecting a zero point from AC power voltage during a constant cycle to generate a predetermined width of pulse signal at the zero point and for applying the predetermined width of pulse signal the microprocessor.

Abstract: In a power-factor-corrected electronic ballast, an AC/DC converter comprises a half-bridge electronic self-oscillating inverter powered from non-filtered full-wave-rectified 120 Volt/60 HZ power line voltage, and its resulting amplitude-modulated 30 kHz output voltage is applied to a series-resonant L-C circuit. The 30 kHz voltage developing across the tank capacitor of this L-C circuit is rectified and applied as direct current to an energy-storing capacitor, from which a DC supply voltage is provided to a frequency-converting ballast which, in turn, provides a substantially non-modulated high-frequency AC output voltage used for powering a gas discharge lamp via a current-limiting inductor. Trigger pulses are provided to trigger the inverter into self-oscillation at the beginning of each pulse of DC voltage provided by the unfiltered rectified power line voltage. As soon as the magnitude of the DC voltage across the energy-storing capacitor exceeds a first level, the trigger pulses cease to be provided.

Abstract: A zero-voltage crossing detector includes a transistor circuit in combination with comparator circuitry for determining when the voltage across a soft-switching device crosses zero. The transistor circuit includes a series combination of a detector transistor and a source, or emitter, load resistance coupled across the soft-switching device. The gate, or base, of the transistor is coupled via a resistive voltage divider to a dc supply. The source, or emitter, of the transistor is coupled to the comparator circuitry for comparing the voltage across the load resistance to a zero-voltage reference. During intervals when the voltage across the soft-switching device is greater than the input voltage to the detector transistor, the detector transistor is off, causing the output of the transistor circuit to equal the input voltage.

Abstract: A control device and system for an appliance and methods of making the same are provided, the control device having a control unit to energize the coil of a relay with a power source at substantially a desired lead point on the voltage wave cycle thereof so as to tend to cause the contacts of the relay to subsequently close substantially at a certain point on the voltage wave cycle each time a load is to be interconnected to the power source whereby a lag time period exists between the desired lead point and a certain point, the control unit having a sensing unit to sense the lag time by detecting when the coil current of the relay coil decreases momentarily by the contacts initially closing during that particular cycle of operation of the control device, the control unit having a unit to automatically adjust the desired lead point should the sensed lag time on a certain previous cycle of operation not cause the contacts to close substantially at the certain point in order to tend to cause the contacts to clo

Abstract: A three-phase transformer is supplied by a three-phase AC line voltage. Two phases are connected via switches comprising head-to-tail connected thyristors. The third phase is connected directly to the transformer. The switches are of the zero voltage switching type. Under steady state conditions, the start of each series of cycles is obtained by closing in a fixed order a first switch at a time near the zero-crossing of the voltage across it (alternating between series of cycles the sign of the derivative of the voltage across it immediately before it is closed) and then the second switch approximately 90.degree. after the first switch. The duration of a series of cycles if 570.degree. plus a null or integer number of periods of the AC line voltage. This is achieved by counting thyristor firing command signals from pulse transformers driven by monostables.

Abstract: A multiresonant DC to DC converter which operates at a substantially fixed frequency yet maintains relatively constant efficiency levels despite wide variations in input voltage. The multiresonant converter includes a first transistor switch in series with the DC voltage supply source and the load and a second transistor switch in parallel with the DC voltage supply source and the load. The switching action of the first transistor switch is controlled as a function of the supply voltage input to the converter while the duty factor of the second transistor switch is controlled in accordance with the output voltage of the converter.

Abstract: A heater control system has a phase control circuit coupled between a power supply and a heater to control the phase of current to be supplied to the heater. A short circuit device is connected to short circuit the phase control circuit to allow current from the power supply to flow directly to the heater. A control circuit allows the phase control circuit to operate for a predetermined time after the power supply is turned on, and after the elapse of this predetermined time, shorts the phase control circuit with the short circuit device. In a modification, the phase control circuit may be normally inactive, and be energized to reduce current to the heater when the power supply is being drained by another device.

Abstract: AC power loads such as from transformers, motors, high in-rush heaters, air conditioners, etc., are controlled by the use of bipolar transistors, FET transistors, gate turn-off SCRs and IGBT to turn on the load at zero-cross over and to turn off the load at any point in the sine wave which produces the desired amount of power. This reduces RFI and virtually eliminates di/dt at turn on since both voltage and current start at the same zero cross-over, and hence will improve the power factor. Both analogue and digital logic systems can also be utilized to produce this type of phase control, and a wide variety of possibilities are available such as serial and parallel input, the use of full wave bridge control, etc.

Abstract: A method and apparatus for precisely controlling the temperature of a heated tip are disclosed. The temperature of a thermocouple within the tip is sensed at a selected rate. The sensed temperature is compared with a preselected temperature set by a user. The power provided to heat the tip is varied to cause the tip to achieve the selected temperature. If an AC power source is used, the temperature sensed at each zero crossing of the power source and the amount of power provided within that cycle is based on the temperaature of the tip sensed within the same cycle. The duration of time that heat is applied to the probe within the cycle is varied to achieve the desired temperature. If a DC power source is used, the temperature of the tip is sensed at selected intervals. The sensed temperature controls the amount of power provided to heat the tip. The exact temperature of the tip is thus advantageously controlled to provide the desired heating.

Abstract: A method and circuit for reverse phase control of alternating current being delivered to a load are disclosed wherein voltage-controlled semiconductor switches, such as MOSFET's and IGBT's, are used as electronic switches to conduct voltage during the leading edge of the AC voltage cycle and conduction is terminated when the desired phase angle of the current flow has been reached. The disclosed method and circuit eliminate the need for zero crossing detection of the AC waveform and ensure that the voltage-controlled switches are always turned on before the zero crossing thereby minimizing radiated interference and incandescent lamp hum. The method used is primarily digital in nature making mechanical input or electronic input for the power control equally efficient to implement.

Abstract: An electronic dimming apparatus adapted for use in a distributed dimmer system, the distributed dimmer system comprising at least one alternating current supply; a plurality of lamp loads at spaced apart locations; a plurality of dimmer enclosures, the dimmer enclosures adapted to be located at spaced-apart locations in proximity to the lamp loads, each of the dimmer enclosures containing at least one semiconductor power controller coupled between a power input and a power output, the power output coupled to at least one of the lamp loads by at least one power connector; elongated power conductors coupling the power input of each of a plurality of the dimmer enclosures to the alternating current supply, at least a portion of the elongated conductors disposed within an elongated, substantially rigid enclosure, the enclosure mounting a plurality of power connectors at spaced-apart locations; and a trigger for variably controlling the average power supplied to the lamp load, the trigger responsive to at least a

Abstract: A method and device for controlling a bridge circuit for providing current or power to a load. The bridge comprises two transistors including flywheel diodes and connected in series between positive and negative power supply rails for conducting current to or from the load under control of a control drive circuit. An LC-circuit is connected between the bridge circuit and the load. The bridge voltage (E) of the connection between the two transistors and the current (I) through the inductance of the LC-circuit are monitored and a firing pulse is supplied to one of the transistors.

Abstract: A control circuit for heat fixing device for use in an image forming apparatus is disclosed. The control circuit comprises device for detecting a power source voltage, device for detecting zero-crossing points of the power source voltage, device for determining frequency of the source voltage from the detected zero-crossing points, device for determining a power supplying time based on the detected power supply voltage and the power source frequency, device for controlling the power supply to a load based on the determined power supply line, in such a manner that a given power is automatically applied to the load against the change or fluctuation of the power supply source.

Abstract: A primary winding of a transformer is coupled to a source of input voltage and to a controllable switch. The switch is responsive to a first control signal for generating output pulses in the transformer secondary windings. A supply circuit is responsive to the output pusles and generates a first supply voltage. A capacitor charging circuit includes a thyristor that is coupled to one of the transformer secondary windings. The thyristor receives the output pulses for providing charging pulses to the capacitor for generating a second supply voltage. A control circuit is coupled to the thyristor for varying the number of output pulses occurring relative to a given number of charging pulses to regulate the second supply voltage.

Abstract: A power control arrangement for controlling the power output of a plurality of resistive heating elements (9a, 9b) comprises a multi-position switch (S1, S2) for connecting the heating elements in series and in parallel, a zero voltage switch (4), AND-gate (5), clock pulse generator (6), shift register (7) and semiconductor device (8) such as a trail which cooperate to vary the duty cycle applied to the heating elements in both serial and parallel modes.

Abstract: A temperature controller compares a temperature detection signal outputted from a temperature sensor with a set temperature preliminary set in a temperature setting circuit. According to a result of the comparison and before a zero-cross point of an AC voltage applied from a commercial AC source to a heating member, a driving circuit of the temperature controller outputs a driving signal to a thyristor to turn ON the thyristor at the zero-cross point. Then the AC voltage is applied to the heating member via the thyristor. Since the determination of turning ON or OFF the thyristor is made before the zero-cross point of the AC voltage applied through the thyristor, the thyristor may surely be turned ON or OFF at the zero-cross point to prevent electromagnetic wave noises from occurring.

Abstract: The proposed invention is an energy saving load control device primarily intended for inductive loads (i.e., fluorescent lighting, motors, etc.) operating from an alternating current (AC) source. The proposed device switches the load voltage off at arbitrary positions in the sine wave and simultaneously provides a commutating path for any inductive current. By switching the load voltage on and off and providing a commutating current path reduced energy consumption is realized.

Abstract: A multi-resonant-switching network that operates under switching conditions that are favorable to both the active switch and the diode that constitute the switch. In a zero-current multi-resonant switch, the resonant circuit is formed in a T-network with resonant inductors in series with the switching devices. In a zero-voltage multi-resonant switch, the resonant circuit is formed in a .pi.-network with resonant capacitors connected in parallel with the switch. In this way, the two networks are dual. During operation of a multi-resonant converter, a multi-resonant switches forms three different resonant circuits depending on whether the active switch and diode are open or closed. This results in operation of the converter with three different resonant stages in one cycle of operation. In practicing the present invention, certain rules are applied to derive a ZVS-MRC from a PWM converter.

Abstract: The present device includes a bridge circuit with a first intermediate terminal and a second intermediate terminal and with one leg of the bridge circuit being a heating element. Connected across the power lines of the bridge circuit is a main bidirectional switching circuit (having a gate element) which is turned on bidirectionally by control signals developed by an R-C circuit connected to the gate element. The resistors of the R-C circuit are for the most part integral components of two photoconductor isolator devices. These last mentioned resistors provide a low resistance after their associated LED's are turned on and the one of them whose associated LED turns off at the zero crossover remains at a low resistance value for a period of time after its associated LED's has turned off. In addition the present device includes a circuit to bypass the control signal which ordinarily would go to the main capacitor of the R-C circuit in the event that an overcurrent situation (e.g.

Abstract: A generalized multi-resonant switch that combines current-mode and voltage-mode resonant switches. Application of the multi-resonant switch in zero-voltage switched multi-resonant converters results in reduction of the voltage stress to the switching transistor, increase of the load range and reduction of the switching frequency bandwidth. Each embodiment of the multi-resonant converter includes a multi-resonant switch having an active switch, a passive switch and reactive components for causing the active and passive switches to operate in a multi-resonant manner.

Abstract: An improved dimming apparatus adapted for use in distribution dimming systems, in which dimmer enclosures each containing at least one semiconductor power controlling means are located in a plurality of spaced apart locations, each such enclosure located in proximity to at least one of its associated lamp loads. The disclosed dimming apparatus achieves unique advantages in the application through the use of a semiconductor power controlling means capable of modulating the instantaneous amplitude of the voltage or current supplied to the lamp load under the active control of its control input, a signal being applied to the control input of the power controlling means such that an output waveform is supplied to the lamp load in which at least one transition between a substantially off condition and a substantially on condition occurs during substantially each discrete half-cycle of the AC source and the duration of the transition is increased to suppress electro-magnetic interference.

Abstract: A circuit for operating an electromagnet of a feeder or vibrator incorporate phase control for a triac used for oscillating the feeder at line frequency or at a selectable subharmonic frequency.

Abstract: A power supply is disclosed which comprises a ferroresonant circuit, the ferroresonant circuit including a transformer with a core of magnetic material, a primary winding, a secondary winding, and reactive means coupled with at least one of the windings. The transformer also has at least one bias winding. An alternating voltage is applied to the ferroresonant circuit, the alternating voltage having a frequency that is approximately equal to a resonant frequency of the ferroresonant circuit. An output circuit is coupled to the secondary winding. A signal from the output circuit is applied as a feedback signal to the bias winding to control DC flux bias of the core. In an illustrated embodiment, the means for applying an alternating voltage signal to the ferroresonant circuit includes an oscillator for generating alternating voltage control signals, and a switching circuit responsive to an input power source for generating the alternating voltage signals under control of the oscillator.

Abstract: A circuit for regulating the output of a DC power supply that substantially eliminates turn-on transients induced by the switching of a silicon-controlled rectifier (SCR). A zero-crossover detector senses the AC voltage waveform of an applied power source and provides a trigger signal at the zero-crossing point. The trigger signal is applied to cause induction of the SCR's and raise the output voltage when the power supply output drops below a regulated value, and is interrupted so as to inhibit conduction of the SCR's and decrease the output voltage when the power supply output exceeds the regulated value.

Abstract: A fuser temperature control using a resistive bridge driven power circuit. At the beginning of each positive half cycle of the AC line voltage, the possible firing of the triac is delayed by 100 microseconds. During this delay, the fuser temperature is checked by measuring the foil heaters resistance with a DC bridge circuit. One leg of this bridge circuit contains the foil heater. The other leg of the bridge has a potentiometer to set the temperature of the fuser. The output of the bridge circuit is fed into a differential comparator and D-type flip-flop. This combination gives high gain with very little sensitivity to noise. The differential comparator checks the fuser temperature (foil resistance) relative to the set point temperature (set point potentiometer). It determines whether the fuser temperature is above or below the set point temperature. The D-type flip-flop latches this information to either enable or disable the triac triggering circuitry for each full cycle of the line voltage.

Abstract: In a hybrid relay circuit for supplying current to a load with a AC power supply, an electromagnetic relay is provided and the contact thereof is connected in series to the load and the AC power. The electromagnetic relay is driven by a driving circuit in accordance with an input control signal, thereby switching the supply of current to the load.

Abstract: An electrically operated control device and system for an appliance and method of operating the same are provided, the system comprising a power source of alternating electrical current that has a repeating voltage wave cycle and a repeating current wave cycle, a load for using the electrical current to provide an output of the load for the appliance, a relay having normally open contacts and a coil for closing the contacts only when the coil is energized, an electrical circuit for interconnecting the power source to the load through the contacts only when the contacts are closed, and a control unit for causing the coil to close the contacts substantially at a certain point on the voltage wave cycle each time the relay coil closes the contacts from the open condition thereof whereby the current flow through the contacts at each closing thereof is at substantially a desired level thereof.

Abstract: Integral sensor controller for an electrical resistance heater, where the heater is constructed from materials such as nickel, balco, platinum, alumel, or like materials which have an appreciable, positive temperature coefficient of resistivity. The resistance versus temperature characteristic of the heater acts as the temperature sensor. A low level D.C. current provides a sensor voltage which is compared to a set point voltage for switching the heater power through a transistor. The relationship of the sensor voltage to the set point voltage is compared by a comparator which is subsequently used to toggle flip flops for switching of the heater power. Circuitry is provided for protection against heater short circuits.

Abstract: A solid state switching regulator is disclosed whereby rectified line voltage, and current is converted by the switching action of On and Off switching elements to produce a regulated voltage output with short circuit protection. The switching element or elements are switched in a manner such that they are turned off and on when no current is passing through them, thus eliminating the switching losses and the energy consuming snubbing networks normally associated with switching regulator devices.

Abstract: The invention concerns a drive interface (1) for an electronic static switch (3) such as a blocking thyristor or a transistorized blocking switch; this interface is inserted between said static switch and a control stage (2) designed to generate a logic control signal. Said interface comprises a circuit (5) for detecting the voltage across the two power electrodes of the static switch (3) and a drive circuit (6) receiving the signal emitted from the circuit (5) and the control signal; this drive circuit is designed to assure a polarity on the control electrode (3c) of the static switch such that:said polarity corresponds to blocking the switch when the control signal carries an OFF command, and/or the voltage across the power electrodes is different from 0,said polarity corresponds to the conduction state of the switch when the control signal corresponds to permission to conduct an the voltage across the power electrodes is near 0.

Abstract: A quasi-resonant converter is disclosed as comprising a power source, a load and a resonant switch circuit for periodically connecting the power source to the load. The resonant switch circuit includes a switch for connecting the power source to the load and for disconnecting the power source from the load, and a resonant circuit comprised of a resonant capacitor and a resonant inductor. The switch is operated at a switching frequency in excess of 1 MHz and in the order of 10 to 20 MHz or greater. The resonant circuit is connected to the switch to impose thereon a voltage waveform as developed across the resonant capacitor. The resonant capacitor and the resonant inductor have respective impedances selected to shape the voltage waveform such that a zero-voltage condition is imposed upon the switch when it is disposed to its on state, whereby the parasitic capacitive losses associated with the switch are eliminated.

Abstract: A family of quasi-resonant converters for providing regulated power is disclosed as comprising a voltage source, a load and a resonant switch circuit, for periodically connecting the voltage source to the load. The resonant switch circuit includes a switch, and a resonant circuit comprised of a resonant capacitor and a resonant inductor. The switch is actuated to its first state to permit a current flow in a first direction from the voltage source to the load and to block a current flow in a second, opposite direction, and deactuated to a second state to permit a current flow in the second direction from the load to the voltage source and to block the current flow in the first direction, whereby the quasi-resonant converter is operative in a full-wave mode. More specifically, the switch in its first state couples the resonant capacitor and the resonant inductor together to form a resonant switch circuit.

Abstract: A power converter for converting 60 Hertz line power to 20 kilohertz power for driving a low voltage incandescent lamp (42). A field effect transistor power switch section (12) is connected through bridge rectifiers (10, 32) for charging a capacitor filter (34) with the AC input power. A 20 kHz oscillator (38) drives a half-bridge inverter (36) for coupling the capactitor voltage to the lamp (42) as high frequency power. The conduction of the FET power switch (12) is controlled by a phase locked loop (16) for synchronizing the conduction with the zero crossing points of the AC cycle. A ramp generator (18) and a summing network (20) are responsive to a lamp intensity control (22) for changing the conduction duty cycle of the FET power switch (12) such that a desired lamp intensity is maintained.

Abstract: A line-frequency switching power supply for producing a regulated D.C. output voltage includes a pass element disposed between a rectifier circuit and an output terminal to which a filter is connected. The pass element is enabled when a zero-crossing of line voltage is detected, and switched on when the line voltage exceeds the voltage on the filter capacitor plus the operational drop across the pass element. The pass element is switched off when the output reaches a preselected D.C. output level, tripping a switch. Since the pass element is switched on for only a portion of a cycle of line voltage, power dissipation is minimized and efficiency is kept high. Regulators of type described herein suitably may be stacked on a single secondary winding to produce multiple output voltages, or may suitably function as preregulators for following linear regulators to produce very stable and constant D.C. output voltages with minimum power dissipation.

Abstract: A solid state relay is responsive to a control signal and is used with an impedance load and a source of alternating electrical power. The solid state relay is used to connect and disconnect the load from the source of alternating electrical power. The solid state relay turns on in response to a control signal and to a substantially zero voltage crossing of the alternating electrical power of the source. The solid state relay turns off in response to the control signal and to a substantially zero current crossing of the alternating electrical power of the source.

Abstract: What is proposed is an electronic circuit for controlling the amount of AC power delivered to an inductive or resistive load which continuously measures the actual phase lag between the load current and applied voltage and automatically adjusts the firing angle to provide the desired amount of AC power. The circuit includes an auxiliary on/off input with soft start and independently adjustable time delays for the on and off functions and also incorporates an input for remote power level control and features a half-wave rectified mode which delivers pulsating DC power to the load.