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Led switch circuitry for varying input voltage source

A voltage source and LED array technology, applied in the field of switching circuits, can solve the problems of large voltage drop, current source G power loss, etc.

Active Publication Date: 2012-03-14
HUIZHOU LIGHT ENGINE LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, if the voltage of the input voltage source V is much higher than the forward voltage of D, then a large voltage drop occurs in the current source G
Such an event can cause significant power loss in the current source G, especially if the current source G is a linear current source

Method used

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  • Led switch circuitry for varying input voltage source
  • Led switch circuitry for varying input voltage source
  • Led switch circuitry for varying input voltage source

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Embodiment Construction

[0033] Figure 2-14 Aspects of a preferred embodiment of an LED array switch device are illustrated. For LED lighting operating with a varying input voltage source, such as a rectified AC source, the switching device according to the invention divides the LED string into a series of multiple LED sections. When the input voltage is low, only the first LED section is lit. As the input voltage increases, the subsequent LED sections switch continuously to form a higher forward voltage string. Conversely, if the input voltage decreases, the sequence is reversed and LED sections are removed from the string starting with the last lit section.

[0034] figure 2 Functional blocks of the proposed circuit are shown. Assume that the LED string is divided into n LED sections D1 to Dn, where n>1. Each LED section can consist of one or more LEDs. G1 to Gn are constant current sources that can be disabled, that is, switched to an open circuit condition by the current sense signal from ...

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PUM

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Abstract

An LED array switching apparatus, comprises: a plurality of LED segments D1 to Dn connected in series, each LED segment having a forward voltage; a voltage supply coupled to the plurality of LED segments; and a plurality of constant current sources G1 to Gn, coupled to outputs of LED segments D1 to Dn, respectively. Each of the constant current sources is switchable between a current regulating state and an open state such that as the voltage of the voltage supply increases, LED segments are switched on and lit to form a higher forward voltage LED string, and as the voltage of the voltage supply decreases, segments are switched off and removed from the LED string starting with the most recently lit segment.

Description

[0001] Cross reference to related applications [0002] This Chinese patent application claims priority to US Provisional Patent Application 61 / 373,058, filed August 12, 2010, the entire contents of which are incorporated herein by reference. technical field [0003] The invention relates to a switch circuit for driving an LED light source. Specifically, a circuit in which an LED is driven by a regulated current source. Background technique [0004] Typically, LEDs can be driven by a current source that regulates the current through the LED to maintain the light output of the LED. figure 1 A typical circuit for driving an LED circuit is shown, where V is the input voltage source, D represents a string of LEDs, and G is the current source. In such a circuit, in order for current to flow through D, the source input voltage of V must be higher than the forward voltage of LED D. [0005] However, if the voltage of the input voltage source V is much higher than the forward vol...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05B37/02H05B44/00
CPCH05B45/48H05B45/395H05B45/37
Inventor 梁华兴萧锦华
Owner HUIZHOU LIGHT ENGINE LTD