Huizhou Light Engine Limited

Kam Wah Siu

Wa Hing Leung

Chung Ping Kevin Lo

Wa-Hing Leung

Siu Hong Wong

Bo Tian

Kwok Hung Poon

Multiple LEDs connected in series are driven by DC voltage that is provided by a diode rectifier connected to a three-phase power source. In order to reduce ripple in the DC voltage, the series-connected LEDs can be divided into a first set and a second set, and a first constant current source is provided that drives the first set, and a second constant current source is provided that drives the second set. The first and second constant current sources are both connected across the outputs of the rectifier circuit, and operate to drive the respective sets of light emitting diodes in alternation. The capability for dimming can be provided, as well as back-up single phase operation. The light emitting diodes can be situated remote from said rectifier and connected thereto by a single phase power transmission system, formed by only two wires.

Method and arrangement for remotely driving light emitting diodes from a three-phase power source via a single phase cable system

Multiple LEDs connected in series are driven by DC voltage that is provided by a diode rectifier, the diode rectifier being connected to a three-phase power source and converting the three-phase currents from the three-phase power source into the DC voltage that is used to drive the light emitting diodes. In order to reduce ripple in the DC voltage, the series-connected light emitting diodes can be divided into a first set and a second set, and a first constant current source is provided that drives the first set, and a second constant current source is provided that drives the second set. The first and second constant current sources are both connected across the outputs of the rectifier circuit, and operate to drive the respective sets of light emitting diodes in alternation. The capability for dimming can be provided, as well as back-up single phase operation.

Method and circuit for driving light-emitting diodes from three-phase power source

An LED array switching apparatus comprises, on a single PCB substrate: a plurality of LED arrays Dto Dn connected in series, each LED array having a forward voltage; an AC voltage supply coupled to the plurality of LED arrays; and a plurality of constant current sources Gto Gn, coupled to outputs of LED arrays Dto Dn, respectively, each of the constant current sources being switchable between a current regulating state and an open state such that as the voltage of the AC voltage supply increases, LED arrays are switched on and lit to form a higher forward voltage LED string, and as the voltage of the AC voltage supply decreases, LED arrays are switched off and removed from the LED string starting with the most recently lit LED array.

Light engine with LED switching array

An LED lighting circuit where the configuration of the connection of two or more LEDs are changed from parallel to series through the use of solid state switches depending on whether the voltage level from an AC source measured by a voltage detector exceeds the sum of the forward voltages of the LEDs. Also, a method of activating LEDs in an LED array lighting apparatus involving applying a rectified alternating current to two or more LEDs, each LED having a forward bias voltage; comparing the rectified alternating current to the sum of the forward bias voltages of the two or more LEDs; and changing the circuit configuration of the two or more LEDs between a parallel connection and a series connection with respect to the rectified alternating current depending on whether the rectified alternating current exceeds the sum of the forward bias voltages of the two or more LEDs.

AC LED array configuration switching circuit triggered by source voltage level

A device and method for reducing current ripple to a light emitting diode array having a single stage power factor correction driver with an output voltage ripple that is reduced by using a linear current regulator connected in series between the single stage power factor correction driver and the light emitting diode array, which actively adjusts an equivalent impedance of the linear current regulator in correspondence with the output voltage ripple of the single stage power factor correction driver.

Method and apparatus for cancelling output current ripples in LED driving circuits

A circuit for driving a light emitting diode (LED) comprises: an alternating voltage power supply, comprising a triac dimmer having a firing angle and output terminals that provide power to the LED; a zero crossing detector that detects a polarity change of the alternating voltage provided by the alternating voltage power supply and provides a zero crossing output signal indicative of the zero crossing; a timer triggered by the zero crossing output signal that generates a timer output signal during a time period of the timer; and LED power circuitry that reduces current to the light emitting diode based upon timing characteristics of the timer output signal.

Method and apparatus for controlling brightness of light emitting diodes

A power-factor-corrected power supply adapted to supply power to one or more light emitting diodes (LEDs), comprises: a triac dimmer electrically connected between an alternating current source and a bridge rectifier; a damping circuit electrically connected between the alternating current source and the bridge rectifier; a bleeder circuit configured to conduct current between a supply terminal of the bridge rectifier and ground only when a triac in the triac dimmer is not conducting current; a fast startup circuit configured to conduct current between the supply terminal of the bridge rectifier and a voltage supply terminal of a power-factor-corrected controller when the triac dimmer is initially turned on until a supply voltage capacitor coupled to the voltage supply terminal of the power-factor-corrected controller has charged; a dimming slope control circuit configured to reduce a first voltage sensed at a current sensing terminal of the power-factor-corrected controller, such that a reduced amount of current is supplied to the one or more LEDs at a given firing angle, wherein the first voltage is representative of a current flowing through a primary winding of a flyback transformer; and a dummy load circuit provided in parallel with the one or more LEDs to draw a holding current for the triac only after the triac is turned on.

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Hong Kong, China

Kam Wah Siu