Abstract: The present invention provides an LED (Light-Emitting Diode) driving control circuit for controlling a converting circuit to transform an input power source into an output voltage for driving an LED module. The LED module has a plurality of LED strings. The LED driving control circuit includes a voltage detecting circuit and a feedback control circuit. The voltage detecting circuit has a plurality of detection circuits, and each detection circuit is coupled to a terminal of the corresponding LED string to determine whether a voltage of the terminal is higher or lower than a preset value. The voltage detecting circuit generates a feedback signal according to the determination results. The feedback control circuit controls the converting circuit to modulate the output voltage according to the feedback signal.

Abstract: A circuit for driving light emitting diodes includes a first semiconductor switch that is responsive to a driver signal and a freewheeling device coupled between a first supply terminal that provides a supply voltage and a second supply terminal that provides a reference potential. An LED and an inductor are coupled in series between a common circuit node of the first semiconductor switch and the freewheeling device and either the first supply terminal or the second supply terminal. A current measurement circuit is coupled to the LED and provides a load current signal that represents a load current passing through the at least one LED. A first feedback circuit includes an on-off controller that receives load current signal and a reference signal, compares the load current signal with the reference signal and generates the driver signal dependent on the comparison.

Abstract: A system includes a single-inductor-multiple-out (SIMO) converter having storage circuitry in communication with a plurality of output channels, and a controller that controls and measures current flow through the SIMO converter. A signal generator may output switching signals to store current in the storage circuitry and discharge the stored current into the plurality of output channels. The discharged current may be measured and compared to a desired current draw through the output channels over a sample period. A compensator may determine whether to change one or more timing parameters used to control the flow of current through the SIMO converter.

Abstract: A lighting system provides for control of the perceived color of the light emitted by the light fixture. The light fixture has two light sources, a control circuit pulses the two light sources and changes relative duty cycles of the light sources to alter a perceived color output of the lighting fixture, in response to a control signal. Duty cycles of the light sources are a function of the control signal.

Abstract: A circuit for driving a plurality of light sources via a current generator, wherein the light sources are grouped into a plurality of light source sets wherein the driver circuit comprises a plurality of inductive elements, a plurality of switches adapted to selectively connect each light source set in series with one of the inductive elements, and a control circuit configured for driving the switches, so that during a first operation time interval, each light source set is connected in series with a respective first inductive element, and during a second operation time interval, each light source set is connected in series with a respective second inductive element, wherein the respective second inductive element is separate from the respective first inductive element.

Abstract: A system includes a single-inductor-multiple-out (SIMO) converter having storage circuitry in communication with a plurality of output channels, and a controller that controls and measures current flow through the SIMO converter. A signal generator may output switching signals to store current in the storage circuitry and discharge the stored current into the plurality of output channels. The discharged current may be measured and compared to a desired current draw through the output channels over a sample period. A compensator may determine whether to change one or more timing parameters used to control the flow of current through the SIMO converter.

Abstract: Various embodiments of the present invention relate to a switch-mode regulator, and more particularly, to systems, devices and methods of using a switch-mode regulator to regulate an LED current to improve overall LED system efficacy and suppress power consumption of a dimmable LED illumination system. Both high and moderate brightness modes are implemented in an LED driver based on the switch-mode regulator. In the high brightness mode, the LED current is larger than a preferred LED current. In the moderate brightness mode, the LED current is smaller than the preferred LED current, and the LED driver sustains the preferred driver efficiency while the LED current remains as a direct current. Such a switch-mode power supply or regulator may also be used in applications other than the LED illumination system.

Abstract: According to embodiments of the present invention, a flameless candle circuit includes an application-specific integrated circuit (“ASIC”) having a first power terminal, a second power terminal, and an output. The circuit also includes a light-emitting diode (“LED”) and a single-pole switch. The LED is configured to receive a signal from the output of the ASIC. The single-pole switch is configured to selectively provide the battery voltage to at least one of the first power terminal and the second power terminal. Additionally, the single-pole switch is configured to remove the battery voltage from both of the first power terminal and the second power terminal to turn the ASIC off. The ASIC is configured to drive the LED in a first mode when the battery voltage is provided to the first power terminal. The ASIC is also configured to drive the LED in a second mode when the battery voltage is provided to the second power terminal.

Abstract: An LED backlight driving circuit including a boost circuit and a transformer current balance circuit is provided. The boost circuit provides a total current for n LED strings, and the transformer current balance circuit is coupled to the LED strings and includes n?1 transformers. A first LED current-balance-circuit (CBC) includes a switching-transistor connected to a secondary-winding of a first-transformer, and an nth LED CBC includes a switching-transistor connected to a primary-winding of an (n?1)th transformer. An ith (1<i<n, n>2) LED CBC includes a switching-transistor sequentially connected to a primary-winding of an (i?1)th transformer and a secondary-winding of an ith transformer. The passive-transformers are applied in the LED driving circuit to implement current balance/equalization, such that the LED backlight driving circuit is suitable for a system with any odd or even number (greater than 1) of the LED strings connected in parallel, so as to reduce the cost of the system.

Abstract: A multi-channel LED driving system includes a power adapter, a rectifying and filtering unit, a plurality of LED strings, and a plurality of linear regulators, a CC/CV controller, an optically coupled isolator and a PWM controller. The CC/CV controller detects the conducting currents flowing though the LED strings and DC voltage source outputting from the rectifying and filtering unit, and provides voltage compensation of the power adaptor. In addition, the linear regulators slightly modulate the current difference between the LED strings to achieve current-sharing control, thus stabilize the illuminating brightness generating by the LED.

Abstract: A circuit configuration for realizing high impedance in an address drive circuit is provided in order to reduce the number of recovery switches without reducing power recovery efficiency. A mechanism for realizing the high impedance in an address drive circuit during a sustain period of a plasma display panel is provided. By achieving the high impedance, capacitance coupling between an X electrode and an address electrode and between a Y electrode and an address electrode can be cancelled, and a power recovery circuit can be simplified without reducing the power recovery efficiency.

Abstract: A controlling circuit and a controlling method are disclosed. The controlling circuit includes a plurality of switches and a comparator. The first terminals of the switches are respectively coupled to one of a plurality of LED channels. The switches are conducted according to a plurality of switching signals respectively, wherein the switching signals are asserted alternately. The first input terminal of the comparator is coupled to the second terminals of the switches and the second input terminal of the comparator receives a reference voltage for the comparator to compare the voltage of the first input terminal with the voltage of the second input terminal so as to output a comparison result. In this way, whether the LED channels work abnormally or not may be detected. In addition, the hardware cost may also be reduced by employing fewer comparators through a sharing mode.

Abstract: The invention provides a circuit device, embedded in an object, which includes a plurality of light-emitting devices, a motion-actuated switch, a controller and a selector. The motion-actuated switch senses a first motion of the object and generates a first controlling signal. The controller selectively drives the plurality of light-emitting devices to emit lights in a first period in a first sequence and a first flashing frequency according to the first controlling signal. After the first period, the motion-actuated switch senses a second motion of the object and generates a second controlling signal. The controller selectively drives the plurality of light-emitting devices to emit lights in a second period in the first sequence and a second flashing frequency according to the second controlling signal. The selector generates a selecting signal and the controller selectively controls the number of lighting light-emitting devices according to the selecting signal.

Abstract: A lighting device (1) comprises a plurality of LEDs (11-14) producing light (21-24) of mutually different colors. The LEDs are driven in switching cycles (63) with a duty cycle controlled supply current of constant magnitude. In each switching cycle, each LED is first switched ON (61) and then switched OFF (62). In a measuring mode, during one switching cycle (63B), all ON phases of all LEDs are briefly interrupted, except for one LED (11), so that a light sensor (70) measures the light from this one LED. This measurement can be used to adapt the duty cycle of this one LED. In the next switching cycle (63C), the interruption of the ON phases is compensated by extending the ON phases of all LEDs except said one LED, the extension having a duration equal to the duration (?D) of the interruption.

Abstract: A system and method are described in which power is inductively supplied to a product or a package containing a product. This power is received via a coil and used by a light source to further enhance the presentation of the product or packaging. The illuminated light draws more attention to the product or package and thereby increases the probability that a prospective buyer will buy the product. Power is supplied to the package via a coil mounted to a shelf system. The frequency of the power supplied to the shelf coil may be changed to change the frequency at which the light source in the product or package illuminates.

Abstract: A power supply system is provided for a multiple lamp LCD panel. In one aspect, the power supply includes a plurality of transformers for driving a plurality of respective CCFLs. The primary sides of each transformer are coupled in series to thereby reduce the stress on each transformer. For LCD panels that include longer CCFLs, a power supply is provided that includes a plurality of transformers for driving a plurality of respective CCFLs. The primary sides of each transformer are coupled in series and each lamp is coupled to two secondary sides of the transformers, thereby reducing the problems associated with longer CCFL tubes. In any of the embodiments, the power supply can be adapted to convert a high voltage DC signal to high voltage AC used to power the lamps.

Abstract: A discharge-lamp illumination circuit has a DC power supply circuit, a DC-AC conversion circuit, and a control circuit for controlling a voltage from the DC power supply circuit. The DC power supply circuit has a transformer and a first switching element connected in series with a primary coil of the transformer. The activation/deactivation of the first switching element is controlled by the control signal from the control circuit. The transformer is equipped with secondary coils equal in number with the discharge lamps. Each secondary coil is equipped with a second switching element whose activation or deactivation is controlled by a signal from the control circuit. The secondary coils provide different voltages by means of control of the second switching elements.

Abstract: In a ballast circuit for operating a lamp, which comprises a bridge circuit and a control circuit for controlling the bridge switches, the control circuit comprises a microprocessor. The control signal for controlling the switches is generated by a separate circuit comprising a signal generator, a timer, two comparators and two reference signal generators. The microprocessor is used only to set the reference signals to the desired values, thereby dimming the lamp.

Abstract: A circuit that includes a latch and an oscillator is attached to a common lamp control switch to cause the lamp to flash when the switch is manipulated in accordance with a prescribed pattern. The flashing draws attention to the lamp and is used, for example, in an emergency. In a first embodiment, the circuit is placed in parallel with the switch. In a second embodiment, the circuit is placed in series with the switch. In both embodiments, the circuit is small enough to fit within an existing switch box.

Abstract: A limited power, gaseous discharge lighting system, particularly suitable for use with suspended ceilings and for safe installation without shock and/or fire hazard and for rearrangement by non-electricians without special tools or experience, the light output of which is controlled by an electronic controller which responds to the ambient light available. The system uses non-armored flexible cables to supply individual relocatable gaseous discharge lighting fixtures and dimmers, and the cables are individually plugged into receptacles which furnish power strictly limited to permit the safe use of the cables, plugs and receptacles. High frequency operation permits efficient operation with rated light output and an electronic controller furnishes additional versatility and economy.

Abstract: An energy saving electroluminescent sheet or panel adaptable to lighting of writing or drawing sheets to permit writing thereon in the dark or to lighting sheets to permit reading of written or other intelligible matter thereon. The luminescent sheet or panel has a light field composed of a number of electrically activatable light segments adaptable to activation independently or in sequence at an intermittent rate or frequency sufficient that the normal eye persistence of observers will produce in effect a coherent light output from the entire light field or selected portions of the light field with a relatively small power source. The light segments can be aligned in any of a number of relationships such, for example, as in side-by-side relation, in radially extending relation or in circumferentially relation.

Abstract: A tricolor fluorescent lamp operating on a DC power source is disclosed herein. The lamp comprises an outer envelop defining therein a sealed space in which an ionizable medium is filled at low pressure. Disposed within said outer envelop are three tubular envelops of a generally inverted U-shaped configuration which define correspondingly three separate discharge paths and which are coated with respective fluorescent substances emitting different colors. Three sequentially energized anodes are located within the sealed ends of the respective envelops and a common cathode is disposed in adjacently facing relation with the open ends of the envelops, such that the three envelops can be sequentially energized to emit the specific colors which are additively mixed in various proportions to produce a desired color as emitting from the whole lamp.

Abstract: A high frequency drive circuit operating as a push-pull, Class C oscillator for driving a high-intensity, gaseous discharge lamp and avoiding the use of a relatively large ballast coil. A highly stable power supply for operating in conjunction with such circuit is also provided.

Abstract: An AC memory drive type self-shift type gas discharge panel which can prevent an accidental erroneous discharge caused by distributed abnormal charges. Abnormal charges may accumulate to a significant extent at the ends of the shift channels having write discharge cells and shift discharge cells regularly arranged. A path for leaking the abnormal charges is provided in the dielectric layer covering the electrode defining the discharge cells at the end of the shift channels.

Abstract: A system for alternately flashing two groups of signal lamps, as commonly employed for emergency and police vehicles, school buses, or the like, is provided with a lamp failure indicating circuit comprising two separate relay coils connected, respectively, as parts of current load lines to the lamp groups so that each coil normally will act through a contactor to energize a pilot circuit, thus causing a pilot lamp to be lighted so frequently when all the signal lamps are functional that the pilot lamp appears to be steadily illuminated; yet a relay coil will not so act, and the pilot lamp then will flash intermittantly to indicate a lamp outage, when a signal lamp on the load line of either coil does not function. In one embodiment, each relay coil has a contactor of its own in a separate branch of the pilot lamp circuit; in another, the two relay coils act alternately to displace a common contactor in the pilot lamp circuit.

Abstract: In a vehicle, pulses are passed from a central pulse generator to accessories such as a heater clock, a turn indicator, and a flasher. The indicator and flasher control appropriate vehicle indicator lights with the pulses. Switches in the indicator and flasher enable a gate which passes the pulses from the generator through the indicator, or flasher, to the lamps.

Abstract: A flasher circuit is disclosed for use with a conventional automotive turn signal system. The flasher circuit comprises a flasher relay under the control of a free-running multivibrator. The multivibrator takes the form of a pair of intercoupled logic gates and an inhibiting means, in the form of a logic gate, disables the multivibrator when the turn signal switch is open and enables it so long as the turn signal switch is closed. The inhibiting logic gate is supplied with logic signals from the output of the multivibrator and a voltage sensing circuit connected with the turn signal switch. The flasher circuit is a two-terminal device and may be substituted for the well known hot-wire flasher without the circuit changes in the turn signal system. The logic gates preferably take the form of an integrated circuit on a single chip.