A CCFL power converter circuit is provided using a high-efficiency zero-voltage-switching technique that eliminates switching losses associated with the power MOSFETs. An optimal sweeping-frequency technique is used in the CCFL ignition by accounting for the parasitic capacitance in the resonant tank circuit. Additionally, the circuit is self-learning and is adapted to determine the optimum operating frequency for the circuit with a given load. An over-voltage protection circuit can also be provided to ensure that the circuit components are protected in the case of open-lamp condition.

High-efficiency adaptive DC/AC converter

A fluid treatment system is disclosed that includes a control unit that controls the overall operation of the fluid treatment system. A ballast circuit is coupled with an electromagnetic radiation emitting assembly. In the preferred fluid treatment system, the ballast circuit is inductively coupled with the electromagnetic radiation assembly. The inductively coupled ballast circuit inductively energizes an electromagnetic radiation emitting device that is located in the electromagnetic radiation emitting assembly in response to a predetermined electric signal from the control unit. In addition, the fluid treatment system includes a radio frequency identification system that is used to monitor various functional and operational aspects of the electromagnetic radiation emitting assembly and a filter assembly used in the fluid treatment system.

Water treatment system with an inductively coupled ballast

A universal ballast control circuit allows a universal ballast to accommodate a gas discharge lamp within a relatively wide wattage range using a low-speed microcontroller. The control circuit drives the ballast to start, run and dim a particular lamp type by providing a control voltage signal to a conventional inverter MOSFET driver to effect dynamic and selective changes in the duty cycle and the frequency of the inverter signal. In one aspect of the invention, the control circuit comprises a generator for generating a periodic analog voltage signal, a source for producing a DC voltage signal, a controller which includes a low-speed microcontroller for varying the frequency of the periodic analog voltage signal and the magnitude of the DC voltage signal, and a comparator for comparing the periodic analog voltage signal and the DC voltage signal to produce a control voltage signal. In another aspect of the invention, the control circuit comprises a generator for generating a periodic analog voltage signal, a controller for controlling the shape of the periodic analog voltage signal, and a comparator for comparing waveforms of the periodic analog voltage signal with the waveforms of two DC threshold voltages to generate a control signal. The present invention allows for the control circuit to be powered by a power supply signal either derived from an inverter half-bridge MOSFET driver, extracted from a boost inductor of the boost converter or generated by an appropriately configured dedicated miniature switch mode power supply. Finally, control circuit can be utilized to drive PFC circuity in a feedback configuration to regulate the level of boost converter output voltage signal.

Universal ballast control circuit

A fluid treatment system (10) is disclosed that includes a control unit (102) that controls the overall operation of the fluid treatment system (10). A ballast circuit (103) is coupled with an electromagnetic radiation emitting assembly (14). In the preferred fluid treatment system (10), the ballast circuit (103) is inductively coupled with the electromagnetic radiation assembly (14). The inductively coupled ballast circuit (103) inductively energizes an electromagnetic radiation emitting device (60) that is located in the electromagnetic radiation emitting assembly (14) in response to a predetermined electric signal from the control unit (102). In addition, the fluid treatment system (10) includes a radio frequency identification system (124) that is used to monitor various functional and operational aspects of the electromagnetic radiation emitting assembly (14) and a filter assembly (16) used in the fluid treatment system (10).

Radio frequency identification system for a fluid treatment system

An LED driver circuit and method are disclosed where an array of light emitting diodes have a transistor connected to each respective array of light emitting diodes. A PWM controller has an input for receiving a voltage reference and an output connected to selected transistors for driving selected transistors and setting a PWM duty cycle for the selected arrays of light emitting diodes to determine the brightness of selected light emitting diodes. An oscillator is connected to the PWM controller for driving the PWM controller.

LED driver circuit and method

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.

Antonio Marques

Papers

Symmetry control circuit and method