Class / Patent application number | Description | Number of patent applications / Date published |
315225000 | Periodic switch cut-out | 10 |
20080252228 | Hid Ballast - A method and apparatus are disclosed for providing current to a load. The apparatus includes a full or half bridge switching circuit, including at least one switching element for supplying power to a load when switched on and means for switching a state of the switching element only at a time when a substantially zero voltage is applied across the switching element. | 10-16-2008 |
20080265793 | APPARATUS AND METHOD TO PROVIDE A HYBRID LINEAR/SWITCHING CURRENT SOURCE, SUCH AS FOR HIGH-EFFICIENCY, WIDE DIMMING RANGE LIGHT EMITTING DIODE (LED) BACKLIGHTING - A hybrid power supply provides powers to a load, such as a light emitting diode (LED) backlight display, using pulse wave modulation (PWM) enable signal to control activation of a linear power supply and a switching power supply. During an initial part of an active portion of a duty cycle of the PWM enable signal, the linear power supply is activated to supply the load with constant current. During the remainder of the active portion of the duty cycle of the PWM enable signal, the linear power supply is deactivated and the switching power supply is activated to provide current to the load. A bias current and voltage may be provided to the LED during an inactive portion of the duty cycle of the PWM enable signal. The hybrid power supply combines the high efficiency of the switching power supply with smooth dimming control at low luminance of the linear power supply. | 10-30-2008 |
20080272710 | Reference Current Generating Circuit, Organic El Drive Circuit and Organic El Display Device Employing It - An organic EL display device having an organic EL drive circuit has a reference current generation circuit that switches the column line drive in response to changing of the dot arrangement of R, G and B through changeover switch circuits. Three D/A converter blocks constituted by a plurality of switch circuits and a plurality of output side transistors of a current mirror circuit are provided to produce reference currents for R, G and B that are selectively switched by a first, a second and a third changeover switch circuit. As a result, the D/A converter blocks corresponding to the respective terminal pins dynamically produce drive currents for the respective terminal pins so as to correspond to the dot arrangement of R, G and B on the organic EL panel. | 11-06-2008 |
20080278088 | Ballast With Ignition Voltage Control - A ballast ( | 11-13-2008 |
20080278089 | ACTIVE LAMP CURRENT CREST FACTOR CONTROL - Ballasts with crest factor control are provided. During a transition to a given half cycle steady state, the current provided to reach the steady state is varied, such as turned off for a short period. This reduction during the transition may reduce or eliminate overshoot. The crest factor control is active, such as altering the timing or number of on/off/on switchings used to control crest factor. The active control may be based on any information, such as time, lamp voltage feedback, or other lamp dependent feedback. | 11-13-2008 |
20080290811 | POWER SOURCE UNIT FOR DISCHARGE LAMP AND METHOD OF CONTROLLING THE SAME - A switching element is switched at a high frequency in accordance with control by a pulse generating circuit by using a D.C. power source portion as a power source, which results in that a discharge lamp is driven with a D.C. current through a smoothing circuit. A current detecting resistor detects the lamp current caused to flow through the discharge lamp, a current controlling circuit amplifies a deviation between the detected lamp current value and a preset current reference value, and the resulting value is applied to a feedback terminal (F/B) of the pulse generating circuit through a gain setting circuit. A gain changing circuit changes a loop gain of a feedback control system including the switching element, the smoothing circuit, the discharge lamp, and the pulse generating circuit at an output point of the gain setting circuit in correspondence to a fluctuation in a power source voltage (V | 11-27-2008 |
20090021177 | Diagnosis circuit apparatus and lamp ballast circuit using the same - The present invention relates to a diagnostic device and a lamp ballast circuit. The lamp ballast circuit includes a first power switch, a second power switch, a lamp driven according to switching operations of the first and second power switches, a controller for controlling the switching operations of the first and second power switches, and a diagnostic device. The diagnostic device senses a voltage waveform applied to the lamp to determine an end of lamp life (EOLL) condition and an over-voltage, senses a filament voltage of the lamp to determine a filament connection state of the lamp, and determines an over-voltage of a voltage applied to the controller. | 01-22-2009 |
20090115340 | METHOD AND SYSTEM FOR ELIMINATING DC BIAS ON ELECTROLYTIC CAPACITORS AND SHUTDOWN DETECTING CIRCUIT FOR CURRENT FED BALLAST - A system and method is provided that eliminates DC bias on at least one of a first electrolytic capacitor and a second electrolytic capacitor of a bipolar junction transistor (BJT) based inverter ballast having a shutdown control circuit in association with only one of at least two BJT switches. A duty cycle dependent capacitor is connected in a series with a bus of the ballast, and a resonant circuit, including primary winding of the output transformer and a resonant capacitor. A balancing/charging resistor is connected at one end between the first electrolytic capacitor and the second electrolytic capacitor, and at another end to the duty cycle dependent capacitor and the resonant circuit. | 05-07-2009 |
20090261745 | Enhanced trip resolution voltage-controlled dimming led driving circuit - Each driver circuit for a six-by-four array of light emitting diodes illuminating a pushbutton switch switches three pairs of the light emitting diodes between series connection and parallel connection based on changes to an applied input voltage. Driving six light emitting diodes instead of only four allows illumination of a larger area and improves power efficiency at higher applied input voltages, while retaining dimming compatibility at low voltage levels. Each driver circuit also includes a rectifier allow illumination of the pushbutton switch with direct current voltages of either polarity. The quiescent current limiting resistance is split into multiple resistors for further improved power efficiency. Each driver circuit also includes a bridge rectifier to allow illumination of the pushbutton switch with direct current voltages of either polarity or alternating current voltages. | 10-22-2009 |
20130229127 | Computer Lighting Control - The present invention relates to a method and system that provides independent control over lighting within a computer case. Each inverter module is provided with its own switch to facilitate independent control of illumination. Preferably, the switches are located in a bus that fits within a drive bay and the inverter is directly mounted onto the housing that contains the switch. In another embodiment, the inverter is integrated in a printed circuit board that is inserted into the card slots (e.g. ISA, VESA, PCI, and PCI-Express card slot) on the mother board of the computer. Therefore, the on and off of CCFL inverter can be controlled by software application through the ISA, VESA, PCI, or PCI-Express bus. | 09-05-2013 |