Patent
Symmetry control circuit and method
TLDR
In this paper, a method and circuit for controlling the flow of current through a load is presented, where an oscillator generates a pulse signal of constant frequency and a pulse width modulator adjusts the duty cycle of the pulse signal in response to a dimming level signal input indicative of the desired level of current flow through the load.Abstract:
The present invention provides a method and circuit for controlling the flow of current through a load. In a preferred embodiment, an oscillator generates a pulse signal of constant frequency. A pulse width modulator adjusts the duty cycle of the pulse signal in response to a dimming level signal input indicative of the desired level of current flow through the load. A converter receives the pulse signal as an input and converts it into an AC signal, the frequency of which follows the frequency of the pulse signal and the symmetry of which varies with the duty cycle of the pulse signal. The load is connected into a resonant circuit tuned such that a change in the symmetry of the AC signal changes the level of current flowing through the load.read more
Citations
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TL;DR: In this paper, an LED driver circuit and method are disclosed where an array of light emitting diodes have a transistor connected to each respective array of LEMD, and an oscillator is connected to the PWM controller.
References
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Patent
Power supply for a high intensity discharge or fluorescent lamp
TL;DR: In this paper, the inverter is driven by a switching regulator that is supplied with unfiltered, rectified ac power, and a filter capacitor, connected across the regulator output, is sufficiently large so as to filter at the frequency of the rectified AC input.
Patent
Fluorescent lamp controllers
TL;DR: An electronic controller for fluorescent lamps includes a DC-to-AC converter which supplies high frequency current to the lamps and a preconditioner stage which includes a switched mode power supply connected to accept line power and produce a DC input for the DC to AC converter as mentioned in this paper.
Journal ArticleDOI
Asymmetrical pulse width modulated resonant DC/DC converter topologies
TL;DR: Asymmetrical pulse width modulated (APWM) DC-DC resonant converter topologies which exhibit near zero switching losses while operating at constant and very high frequencies are presented in this paper.
Patent
Two-wire electronic dimming ballast for gaseous discharge lamps
TL;DR: In this paper, a low cost high frequency electronic dimming ballast for gas discharge lamps is disclosed which eliminates the need for external primary inductance or choke coils by employing leakage inductance of the transformer.
Patent
Two-wire electronic dimming ballast for fluorescent lamps
TL;DR: In this paper, a low cost, high frequency, solid-state dimmable fluorescent ballast is disclosed which utilizes a resonant bridge inverter to provide high frequency sinusoidal power to the lamps.