Abstract: A short arc lamp driving circuit includes a trigger boosting circuit, a flash current control circuit, and a closed loop exposure control and calibration circuits that, when combined, can produce short pulses of light with short time separation, quasi-continuous illumination light, and meanwhile, an extremely large dynamic range of delivered and/or calibrated light power or energy.

Abstract: A short arc lamp driving circuit includes a trigger boosting circuit, a flash current control circuit, and a closed loop exposure control and calibration circuits that, when combined, can produce short pulses of light with short time separation, quasi-continuous illumination light, and meanwhile, an extremely large dynamic range of delivered and/or calibrated light power or energy.

Abstract: A power supply samples a rectified AC-input waveform and a regulated output voltage and combines them to control an AC-to-DC converter. The operating frequency and/or pulse width modulation of a switched-mode power supply are in large part fixed by a highly filtered output feedback signal to maintain a desired output voltage. A sample taken from the AC-input rectifiers is used in another feedback control signal to drive the operating frequency and/or pulse width modulation slightly up and down as a function of the rise and fall of each rectified-waveform sinusoid. The power delivered to the output, and thus the power demand on the input rise and fall with the instantaneous voltage of the AC input sinusoid. So the power factor is controlled by drawing current in-step with the voltage waveform.

Abstract: A Parallel Charge, Series Discharge method and apparatus for power factor correction and improved efficiency comprising an energy source, two (or more) impedance(s) capable of storing and delivering electrical energy, a switching circuit having one position so that inpedance(s) charge in a parallel mode with a fraction of the electrical energy incoming from one (or more) rectified AC input generator(s), and another position so that inpedance(s) discharge some of the electrical energy stored into the load, the switch having a frequency and duty cycle so that the input current rectified waveform from the energy source will approximate the voltage rectified waveform from the energy source.

Abstract: A Parallel Charge, Series Discharge method and apparatus for power factor correction and improved efficiency comprising an energy source, two (or more) impedance(s) capable of storing and delivering electrical energy, a switching circuit having one position so that inpedance(s) charge in a parallel mode with a fraction of the electrical energy incoming from one (or more) rectified AC input generator(s), and another position so that inpedance(s) discharge some of the electrical energy stored into the load, the switch having a frequency and duty cycle so that the input current rectified waveform from the energy source will approximate the voltage rectified waveform from the energy source.

Abstract: An arrangement for switchably operating one or more gas discharge lamps, such a compact or circline fluorescent lamps, with a single ballast commonly used with a linear fluorescent lamp. One or more capacitors is either in parallel or in series with the gas discharge lamp. When engaged by a switch, the capacitor either shunts or reduces the current to the gas discharge lamp in a manner which allows appropriate starting voltage, appropriate operating current and a plurality of illumination levels of the gas discharge lamp.

Abstract: The present invention is directed to providing a load control circuit for non-linear or negative-resistance loads, such as gaseous-discharge lamps, having improved cost-effective control and control. In accordance with exemplary embodiments, a controlled start feature is provided which is relatively cost-effective to implement and manufacture. Further, by reducing the complexity and costs associated with such functionality, additional functionality can be provided without substantially increasing the cost of the control circuit.

Abstract: An improved power factor DC power supply in accordance with the present invention (100 or 200) employs a power factor correcting network (120), a full-wave rectifier means (122), a pair of filter capacitors (124 and 126), and three current steering diodes (128, 130 and 132). The power factor correcting network (120) includes both an inductor means (136 and 240) and a capacitor (138), the combination configured to improve the power factor DC power supply (100 or 200) presents to the AC power-line (102) by reducing the level of harmonic currents the DC power supply generates on the AC power-line. The filter capacitors (124 and 126) are configured with the current steering diodes (128, 130 and 132) such that the filter capacitors are charged in series and discharged in parallel.

Abstract: Briefly, to reduce switching stresses, employed is a high-frequency AC power source (110) and a current-limiting (ballasting) network (116). The network ( 116 ) includes a high-frequency trap ( 120 ) and an impedance transforming network (122), which is coupled to the AC power source (110) by the trap (120) and which is for connection to a load that includes at least one gaseous discharge (fluorescent) lamp or other non-linear or negative-resistance load (102). The trap, which has the parallel resonant combination of an inductor ( 130 ) and a capacitor ( 132 ), is resonant at a frequency chosen such that the switching-circuit transistor(s) (210, or 230 and 232, or 250 and 252, or 270 and 272, or 708) of the AC power source (110) switch at times when the level of the current (charge flowing) therein and/or the voltage developed there across is zero, preferably, at a frequency slightly higher than a harmonic frequency of the high-frequency AC power source ( 110 ).

Abstract: An improved power factor DC power supply in accordance with the present invention (100 or 200) employs a power factor correcting network ( 120), a full-wave rectifier means (122), a pair of filter capacitors (124 and 126 ) , and three current steering diodes (128, 130 and 132). The power factor correcting network ( 120) includes both an inductor means (136 and 240) and a capacitor (138), the combination configured to improve the power factor DC power supply (100 or 200) presents to the AC power-line (102) by reducing the level of harmonic currents the DC power supply generates on the AC power-line. The filter capacitors (124 and 126) are configured with the current steering diodes (128, 130 and 132) such that the filter capacitors are charged in series and discharged in parallel.

Abstract: A pair of transistors (110 and 112) configured with their channels connected in series. The gate of the "upper" transistor (110) is coupled to a relatively low-voltage, DC power supply voltage by a voltage-clamping and current-steering diode (144); to a relatively high-voltage, DC power supply voltage by the series combination of a current-steering diode (152) and one voltage-clamping zener diode (154 and 156) and coupled to the source of the "upper" transistor by a charge-removing resistor (162).

Abstract: An embodiment of the present invention is a dimmable, high power factor, high efficiency electronic ballast comprising, on a single integrated circuit chip, a shunt regulator, a voltage reference, a high-temperature shutdown, an undervoltage lockout, a timer for start-up and restarting, a variable oscillator, a mode control, an op-amp for receiving a signal proportional to lamp current and for controlling the variable oscillator or the duty-cycle of pulses output in a closed-loop servo, and active power factor correction including an analog multiplier for receiving an AC voltage and an AC current sample, and for multiplying these together to result in a comparison with a DC voltage. The comparison produces a control signal for a MOSFET switch on a boost converter transformer that actively corrects the power factor at a rate set by the oscillator.

Abstract: For coupling one, or more, gaseous discharge lamps to a high-frequency AC power-source a ballasting (current-limiting) network employs a first capacitor, a second inductor, and a transformer having a primary winding coupled to the high-frequency AC power-source by the first capacitor and a secondary winding coupled to the gaseous discharge lamp by the second inductor.

Abstract: For coupling one, or more, gaseous discharge lamps to a high-frequency AC power-source a ballasting (current-limiting) network employs a first capacitor, a second capacitor, and a transformer having a primary winding coupled to the high-frequency AC power-source by the first capacitor and a secondary winding coupled to the gaseous discharge lamp by the second capacitor.

Abstract: For coupling one, or more, gaseous discharge lamps to a high-frequency AC power-source a ballasting (current-capacitor, and a transformer having a primary winding coupled to the high-frequency AC power-source by the first capacitor and a secondary winding coupled to the gaseous discharge lamp by the second capacitor.

Abstract: A single-ended ballast circuit employs a power-factor-correcting network (510); a DC power supply (512); a free-running oscillator (516); a transistor (518); a current-limiting (ballasting) network (520); and two fluorescent lamps (524). The transistor (518) is configured as a switch connected to be responsive to a signal generated (630) by the oscillator (516) and operative to periodically couple a line (734) to a circuit common. The current-limiting (ballasting) network (520) includes an inductor or transformer (740) having a primary winding (744), connected between a DC power-supply potential and the line (734), and a secondary winding (746); a first capacitor (750), connected between the line (734) and circuit common; an inductor (752); a second capacitor (756), connected in series with the inductor (752) across the secondary winding (746); and a third capacitor (754), connected in series with the lamps (524) across the second capacitor (756).

Abstract: A forward inverter ballast circuit employs a free-running oscillator (116); a transistor (118); a current-limiting (ballasting) network (120); and two fluorescent lamps (128). The transistor (118) is configured as a switch connected to be responsive to a signal generated (200) by the oscillator (116) and operative to periodically couple a line (234) to a circuit common. The current-limiting network (120) includes a diode (250) and a transformer (240) having a transformer primary winding (244) connected between a DC power-supply potential and the line (234); a first, tightly-coupled, transformer secondary winding (246) connected between the DC power-supply potential and the circuit common; and a second transformer secondary winding (248). In addition, the current-limiting network (120) includes an inductor (252), a capacitor (254), and another capacitor (256), all connected in series across the second transformer secondary winding (248). The lamps (128) are connected across one of the capacitors (256).

Abstract: An electronic ballast for energizing one or more gaseous-discharge lamps and for regulating the power consumed thereby, the ballast including a power supply for providing a source of DC power between a pair of outputs, a pair of transistors connected as switches in series between the power-supply outputs, the transistors for selectively coupling to the juncture thereof positive and negative potentials, a voltage-conditioning and current-limiting network for energizing the lamp from the potential developed between the transistor juncture and a power-supply common, and a pulse generator for developing pulses for driving each of the transistors in turn whereby a potential is developed at the transistor juncture which alternates as positive-going and negative-going pulses each separated by a dead time, the pulse generator for monitoring the power consumption level of the lamp and responsive thereto operative to vary the frequency and/or the width of the transistor driving pulses whereby the lamp consumption is re

Abstract: An electronic ballast for energizing one or more gaseous-discharge lamps and for regulating the power consumed thereby, the ballast including a power supply for providing a source of DC power between a pair of outputs, a pair of transistors connected as switches in series between the power-supply outputs, the transistors for selectively coupling to the juncture thereof positive and negative potentials, a voltage-conditioning and current-limiting network for energizing the lamp from the potential developed between the transistor juncture and a power-supply common, and a pulse generator for developing pulses for driving each of the transistors in turn whereby a potential is developed at the transistor juncture which alternates as positive-going and negative-going pulses each separated by a dead time, the pulse generator for monitoring the power consumption level of the lamp and responsive thereto operative to vary the frequency and/or the width of the transistor driving pulses whereby the lamp consumption is re

Abstract: A telephone call diverting and answering system. The system includes a telephone call concentrator for diverting a telephone call placed at a telephone set at one of a number of calling stations, from a telephone line connected to the intended telephone set, at one of a large number of called stations, to one of a small number of telephone trunks leading to sets at a number of answering stations. The system further includes an operator console at each answering station, and a traffic director for assigning the call to a particular station by causing the identity of the called station and the number of the diverting trunk to be displayed on the operator console of the assigned answering station.