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 solid state illumination device includes a semiconductor light emitter (106) mounted on a base (110) and surrounded by sidewalls (120), e.g., in a circular, elliptical, triangular, rectangular or other appropriate arrangement, to define a chamber (130). A top element (122), which may be reflective, may be coupled to the sidewalls to further define the chamber. The light produced by the semiconductor light emitter (106) is emitted through the sidewalls (120) of the chamber. The sidewalls and/or top element may include wavelength converting material, for example, as a plurality of dots on the surfaces. An adjustable wavelength converting element (452) may be used within the chamber, with the adjustable wavelength converting element (452) being configured to adjust the surface area that is exposed to the light emitted by the semiconductor light emitter in the chamber to alter an optical property of the chamber.

Solid state illumination device

A sequential burst mode regulation system to deliver power to a plurality of loads. In the exemplary embodiments, the system of the present invention generates a plurality of phased pulse width modulated signals from a single pulse width modulated signal, where each of the phased signals regulates power to a respective load. Exemplary circuitry includes a PWM signal generator, and a phase delay array that receives a PWM signal and generates a plurality of phased PWM signals which are used to regulate power to respective loads. A frequency selector circuit can be provided that sets the frequency of the PWM signal using a fixed or variable frequency reference signal.

Sequential burst mode activation circuit

There is provided a transfer method for selectively transferring pixel control elements onto a planar display substrate. The method can mount prepared pixel control elements easily, accurately, without waste, and at low cost. A plenty of pixel control elements (1) are formed at a pitch (5, 6) obtained by dividing the pitch (105, 106) of the planar display substrate (100) by a natural number. Pixel control elements (1) corresponding to the pitch (105, 106) of the planar display substrate (100) are selectively picked up. The pixel control elements (1) are held by plastic deformation of a transparent thermoplastic resin film (101) formed on the planar display substrate (100) and peripheries of the pixel control elements (1) are fixed by a transparent ultraviolet ray hardening resin film (104).

Pixel control element selection transfer method, pixel control device mounting device used for pixel control element selection transfer method, wiring formation method after pixel control element transfer, and planar display substrate

The described DC to AC inverter efficiently controls the amount of electrical power used to drive a cold cathode fluorescent lamp (CCFL). The output is a fairly pure sine wave which is proportional to an input control voltage. The output waveform purity is ensured by driving a symmetrical rectangular waveform into a second-order, low pass filter at the resonant frequency of the filter for all conditions of line voltage and delivered power. Operating stress on the step-up transformer is minimized by placing the load (lamp) directly across the secondary side of the transformer. When configured to regulate delivered power, the secondary side may be fully floated which practically eliminates a thermometer effect on the operation of the lamp. All of the active elements, including the power switches, may be integrated into a monolithic silicon circuit.

Method and apparatus for controlling a discharge lamp in a backlighted display

An information processing apparatus employs a liquid crystal display and a fluorescent lamp for backlighting the screen of the liquid crystal display. A lighting circuit for supplying alternating current lighting power to the fluorescent lamp receives input power from either a commercial alternating current power source or from a direct current battery. The level of the lighting power supplied to the fluorescent lamp is determined based upon a determination of whether the input power is being supplied from the commercial power source or from the battery.

Information processing apparatus including a control circuit for controlling a liquid crystal display illumination based on whether illuminatio power is being supplied from an AC power source or from a battery

PROBLEM TO BE SOLVED: To provide a power supply in which an LED can be driven with good voltage conversion efficiency even when a plurality of LED loads are driven. SOLUTION: A plurality of step-down chopper type voltage conversion circuits 10 and 20 for converting the voltage of a DC power supply 1 are connected in series, and a first LED load 15 having a high maximum voltage and a second LED load 25 having a low maximum voltage are connected to the output of each voltage conversion circuit 10, 20. Current flowing through each LED load is detected by a detector 16, 26 and the switching elements 11 and 21 of each voltage conversion circuit is subjected to drive control such that the difference between current command values Vref1 and Vref2 is decreased. In particular, the second voltage conversion circuit 20 requires a relatively small step-down rate because it steps down the voltage which is stepped down by the first stage voltage conversion circuit 10, and thereby conversion efficiency can be enhanced. In case of step-up, a voltage conversion circuit such as a step-up chopper is employed. COPYRIGHT: (C)2007,JPO&INPIT

Dc power supply, power supply for light emitting diode, and illuminator

An illumination lighting apparatus has a resonance load circuit including a discharge tube, a power supply circuit for generating DC voltage from commercial AC voltage, and an inverter for converting the generated DC voltage into an AC voltage and supplying the AC voltage to the resonance load circuit. Further, a control circuit is provided which controls electric power supplied to the resonance load circuit in response to operating parameters of the discharge tube immediately after lighting of the discharge tube.

Inverter type illumination lighting apparatus

A device for turning on light allowing the brightness of an inverter-type illumination apparatus to be adjusted without having to install an additional oscillation circuit. The device comprises an active converter which generates a DC voltage from the commercial AC voltage and an inverter which switches the generated DC voltage, includes a capacitor connected in parallel with a discharge tube to be lighted, and supplies a high-frequency current to the discharge tube via a resonance circuit whose resonance frequency is determined according to the equivalent impedance of the discharge tube. The active converter has a triac adjusting the DC voltage, and switching elements of the inverter perform self-oscillation under control of the phase of the resonance current flowing through the resonance circuit.

Device for turning on light and illumination apparatus

The discharge lamp operating circuit comprises two series circuits, each including two switching devices, connected in parallel with the power supply, a series circuit, including a choke coil, a first capacitor, and a parallel circuit with a discharge lamp and a second capacitor, and connected between the middle points of the one and the other series circuit, reverse-direction rectifiers connected in parallel with the corresponding switching devices, said discharge lamp operating circuit turning on and off said discharge lamp by turning on and off the switching devices alternately. In this discharge lamp operating circuit, the timing of switching the switching devices is set from the closed condition to the open condition at a time when the current flowing through the switching devices is almost at zero level.

Kenji Kawabata

Papers

Information processing apparatus including a control circuit for controlling a liquid crystal display illumination based on whether illuminatio power is being supplied from an AC power source or from a battery

Dc power supply, power supply for light emitting diode, and illuminator

Inverter type illumination lighting apparatus

Device for turning on light and illumination apparatus

Discharge lamp operating circuit