Abstract: The present invention relates to a power supply which includes a switching regulator and an over-current detector, having a reference circuit for providing an over-current threshold level. A means is provided by the present invention for adjusting the over-current threshold level without interrupting the system by utilizing a switch to provide an inhibit signal to a fault shut down circuit and for inserting a component into the reference circuit to modify the over-current threshold level to the desired adjustment level.

Abstract: A stabilized power supply which is particularly suitable for use at very high voltages derives its energy from a resonant inverter feeding a transformer and rectifier. The power supply is intended to be operated in a pulsed mode with the generation of each pulse reducing the output voltage below its required value. The output capacitive stages of the power supply are subsequently re-charged and an input switch is rendered non-conductive when the output voltage regains its required value. As it is not possible to switch off a resonant inverter during the course of a cycle, the energy obtained from the inverter during the remainder of the current cycle is fed into another capacitive stage. The second stage may also be utilized as an unregulated output rail of the power supply. The invention is particularly suitable for power travelling wave tube amplifiers.

Abstract: An induction heating apparatus including a thyristor adapted to receive power from a power source, a gating control circuit for generating gating pulses for application to the gating control terminal of the thyristor, a commutating circuit which commutates off the thyristor, and a differentiator connected across the anode and cathode terminals of the thyristor to detect the power consumption of an inductively heated cooking ware. The gating control circuit comprises a gating pulse generator and a smoothing circuit for filtering the signal from the differentiator into a d-c signal which is compared with a reference level to detect the deviation of the power consumption from the reference value. The gating pulse generator is responsive to a potential at the anode of the thyristor to initiate timing action to determine the interpulse period or turn-off time of the thyristor and also responsive to the deviation of power consumption to vary the interpulse period.

Abstract: A push-pull switching dc-to-dc converter using controlled rectifiers as switch elements delivers uninterrupted output current to its load, owing to the inclusion of plural-winding inductors.

Abstract: An LC series resonant regulator is connected across the output of the inverter circuit of a static converter apparatus to vary the output voltage level as the inverter operating frequency varies from a preselected frequency at which the regulator circuit is tuned. The load is coupled across the capacitor element of the regulator and a level detector coupled across the load input. This detector registers variations of the input to the load from a predetermined desired level of load voltage and supplies a feedback signal, indicative of any detected variations, to the control circuit for the inverter circuit element. This control circuit is responsive to a feedback signal to vary the operating frequency of the static inverter so that the regulator varies the output voltage applied to the load to restore the desired voltage level.

Abstract: An automatic electronic reset current cut-off protection circuit for electrostatic precipitator air cleaner power supplies of the type utilizing a ferroresonant transformer having a primary winding, a secondary winding for producing relatively high voltage and a tertiary winding for producing a relatively low voltage. The circuit operates to inhibit power supply operation in the event of an overload in the ionizer or collector cell by sensing a voltage derived from the high voltage and comparing the sense voltage with a fixed reference. When the sense voltage falls below a predetermined value, current through the transformer primary is inhibited for a predetermined time. Current flow is automatically reinstated and the circuit will cyclically cause the power supply to shut down until the fault has cleared. The reference voltage is derived from the tertiary winding voltage resulting in increased sensitivity of the circuit to short duration overload conditions.

Abstract: The braking of an a.c. motor is accomplished by sequence controlled outputs of a shift register circuit which sequentially disconnects the main a.c. electrical excitation from the a.c. motor, connects a full wave rectifier circuit to the a.c. motor and then applies the a.c. electrical excitation to the full wave rectifier circuit resulting in a braking current being supplied to the a.c. motor.

Abstract: Disclosed is a class of power converter which extracts electric energy from a source of A.C. or D.C. power and conveys this energy through series resonant circuits to two or more loads in an independently controllable form.

Abstract: A power supply includes an inverter circuit comprising silicon controlled rectifiers which are driven by a variable frequency control signal. The frequency of the control signal is determined by monitoring the power output requirements of the power supply. Because of the continuous sinusoidal operation of the inverter, the supply generates a very low level of radio frequency interference (rfi).

Abstract: A control apparatus for a switching regulator circuit having a voltage controlled oscillator responsive to any deviation of the output voltage of the switching regulator circuit from a predetermined reference voltage. The voltage controlled oscillator produces a digital pulse stream having a frequency which is varied by the voltage controlled oscillator in response to any deviation of the output voltage of the switching regulator circuit from the predetermined reference voltage. A recovery detector is connected to at least one of the reactors of the switching regulator circuit to ensure that the particular SCR associated with that reactor has fully recovered prior to the next actuation thereof. If the particular SCR has not recovered then the digital pulse which would be distributed to that SCR within the digital pulse stream is held.

Abstract: A method and apparatus for controlling a resonant power module comprising a resonant power circuit which is coupled to a load. First and second switching elements are coupled to the resonant circuit for alternately supplying a flow of current. Trigger generator means are provided for supplying trigger signals to alternately enable the first and second switching elements. A control means is coupled to the trigger generator for operating the power module in a first mode in which the resonant circuit current is controlled by varying the repetition rate of the trigger signals. The control means operates the power module in a second mode by maintaining the trigger signal repetition rate at a fixed limit and controlling the resonant circuit current by varying the on/off duty cycle of the power module.

Abstract: A switching regulator circuit for utilization with power supplies supplying a high DC output current including a plurality of control rectifiers and inductive reactors with sequential gating of the rectifiers at regular intervals for providing overlapped output current pulses from the reactors. An output circuit receives the rippled current comprised of the overlapped output current pulses for reducing the ripple therein. The output circuit includes a choke in series with the output which induces phase shift between the rippled current and the output current. A sensing winding associated with the choke eliminates the phase shift voltage for forming a feedback signal as an input to a control circuit. The control circuit utilizes the feedback signal to control the rate at which the rectifiers are gated sequentially.

Abstract: A switched-mode power supply with mains isolation comprising a primary circuit with a switch, a first secondary circuit working simultaneously with the switch and which generates a non-regulated voltage and a second, non-simultaneous, secondary circuit which forms part of a flyback converter. The sum of the two generated voltages is regulated.

Abstract: A DC-to-AC inverter includes first and second resonant circuit loops each including a capacitor, a primary coil of an output circuit, a silicon control rectifier providing a current path in one direction around the loop, and a conventional diode providing a current path in the opposite direction around the loop. A DC source is connected to supply a charging current through charging chokes to the capacitors in the resonant circuit loops. The silicon control rectifiers are periodically and alternately rendered conductive each to start a cycle of oscillation in one resonant circuit loops, while the DC source provides current to charge the capacitor in the other resonant circuit loop. The charging chokes and primary coils are phased to supply voltages which add to the voltage of the DC source during the charging of the capacitors.

Abstract: A switching regulator includes a DC voltage source having a pair of DC output terminals, a switching transformer having a magnetic core, first and second primary windings and a secondary winding, a first switching transistor connected in series between the pair of DC output terminals through the first primary winding, a second switching transistor connected in series between the pair of DC output terminals through the first and second primary windings, and a rectifier circuit connected across the secondary winding. A pulse width modulator is provided to produce a PWM (pulse width modulated) control signal the duty of which is proportional to the voltage of the rectifier circuit, and the PWM control signal is selectively supplied to one of the first and second switching transistors in response to the low or high circumstance of a load connected to the rectifier circuit.

Abstract: A pair of switching elements are provided between a source of direct current and a bridge type inverter for commutating together. A commutating circuit having a capacitor is connected in parallel with the bridge type inverter to rapidly commutate the bridge type inverter. The commutating circuit operates so as to apply a voltage of inverse polarity to the thyristor of the inverter when a switching element operates.

Abstract: An inverting circuit of the series resonant type and including a pair of SCR's operated at variable off-times for controlling the charging of a battery. A control circuit is provided for gating the SCR's at appropriate times in response to sensed circuit current, and battery voltage. Instantaneous resonant circuit current is monitored to derive timing information for firing the SCR's and for anticipating commutation failures.

Abstract: A DC to DC converter employs resonant switching to turn switching power devices on and off at zero current. Two series resonant circuits are formed by two inductors connected in series between a voltage source and a power switch and a capacitor connected between the junction of the two inductors and a source of reference potential. The values of the two inductors are chosen so that the natural resonant frequency of the second inductor and the capacitor is high compared to the natural resonant frequency of the first inductor and the capacitor. The power switch may be a semiconductor switch, such as a silicon controlled rectifier or a junction transistor. Both non-isolated and isolated outputs may be provided in buck or boost conversion. The converter can be used as a voltage regulator by the addition of output sensing, comparison with a reference voltage, and suitable on-off control.

Abstract: Power supply having means for developing a voltage overload signal representing a current overload condition in the power supply and then reducing the output current from the power supply as a result of the voltage overload signal. The voltage overload signal is applied to a servo or error amplifier to cause the error signal therefrom to change in a manner to reduce the power supply output voltage which in turn is fedback to the said amplifier to cause output current foldback.

Abstract: A switch control system particularly well suited for use in a electromechanical vibrator drive. Solid-state switches and diodes are used in combination with a DC power supply to alternately switch energy between the electric field of the power supply filter capacitor and the magnetic field of the actuator coil of a vibrator in a power resonant mode. The control system includes a variable frequency oscillator and a controllable pulse generator which respectively provide signals for controlling the closing and opening of the switches whereby the frequency and amplitude of movement of a vibratory feeder may be adjusted.

Abstract: A power supply circuit for a high voltage driven device, particularly a magnetron, is described. The power supply circuit comprises first and second switching elements, an inverter circuit including a commutating reactor connected in series with the first and second switching elements and a capacitor connected to a center tap of the commutating reactor, a transformer connected to an output of the inverter circuit, and a third switching element connected in parallel with a series circuit comprising the capacitor, the primary winding of the transformer and a portion of the commutating reactor. When the magnitude of a current flowing in the transformer exceeds a predetermined level, the third switching element is fired to establish a discharge loop for the capacitor through the series circuit whereby the amplitude of the current supplied to the transformer is limited below the predetermined level.

Abstract: A flyback type power supply in which dissipation losses associated with switch transition time are substantially eliminated by performing all switching operations at or near zero current by the use of a plurality of resonant circuits. In a first resonant circuit an intermediate storage capacitor is resonantly charged through an inductor and a first switch until, after a half sinewave of charging current, the voltage on the capacitor is twice the input supply voltage. The capacitor is then discharged through a second switch and the primary inductance of a flyback transformer having rectifiers on the secondary that are back-biased initially so as to provide a resonant current buildup in the primary winding with an amplitude that follows a sinewave function, the primary voltage following a cosine function.

Abstract: A switching type power supply is provided which includes a first and a second SCR with a diode connected in reverse across each of them. The first SCR-diode pair in response to a clock pulse charges a capacitor which when fully charged causes the first SCR current to return to zero, forward biases the first diode and commutates the first SCR off for at least the required minimum turn-off time of the SCR. After the capacitor reaches the peak charge value, the second SCR is selectively triggered to couple the desired portion of the stored energy to the power supply load via a transformer. After the currents in the secondary windings of the transformer reverse, and the capacitor achieves a peak charge of the opposite polarity, the current through the second SCR becomes zero, the second diode is forward biased, and the second SCR is commutated off.

Abstract: A typical "stand alone" precision power DC to AC solid state converter reres a higher DC supply voltage than is usually available from its utility power sources. The disclosed invention is a voltage boost circuit that provides the DC-bus voltage amplitude for precision power DC to AC solid state converters by transforming only the difference between the available raw power DC voltage bus and the required precision DC voltage amplitude. This DC voltage difference obtained by the circuitry of this invention is boot-strapped to the available DC bus to obtain the required precision DC voltage.

Abstract: Circuitry for providing high voltage DC power from commercially available 60 hertz AC utility power. The incoming 60 hertz AC voltage is rectified to a DC voltage. This DC voltage is then converted to a high frequency AC voltage by means of a sine wave inverter. This high frequency sine wave voltage is then converted to a different voltage and rectified by a voltage doubler. The inversion and rectification are under the control of logic circuitry which includes means for sensing line faults to provide circuit protection.