Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Linear constant-current LED driving circuit and method compatible with SCR light modulator

A technology of LED drive and dimmer, which is applied in the direction of electric lamp circuit layout, light source, electric light source, etc., and can solve problems such as control failure of thyristor dimmer, LED flickering, and false shutdown of thyristor dimmer, etc. Achieve the effect of avoiding the false shutdown of the thyristor and improving the compatibility problem

Active Publication Date: 2016-01-27
SHANGHAI LOOALL ELECTRONICS CO LTD
View PDF7 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0015] The disadvantage of this scheme is: from the time t3, the amplitude of the rectified voltage VREC begins to be smaller than the threshold voltage of the LED unit, and the current flowing through the mains drops rapidly from I1 to I2 with a large slope, especially when the LEDs in the LED unit are two Terminal parallel capacitors (such as Figure 1a ) is especially true when smoothing the LED current waveform, which will cause the electrical circuit inside the thyristor to self-resonate. When the resonance amplitude is too large, the thyristor dimmer will be turned off by mistake. When the resonance amplitude is in a critical state At this time, the false shutdown of the thyristor dimmer will occur irregularly and randomly, resulting in the failure of the thyristor dimmer to control the load, and further, it will cause the LED connected to the thyristor dimmer to flicker

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Linear constant-current LED driving circuit and method compatible with SCR light modulator
  • Linear constant-current LED driving circuit and method compatible with SCR light modulator
  • Linear constant-current LED driving circuit and method compatible with SCR light modulator

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Such as image 3 As shown, an LED drive circuit compatible with a thyristor dimmer is powered by mains, and the thyristor dimmer is connected in series to the mains, including a rectifier bridge DB, an LED unit and a combined current source. A combined current source consists of three terminals. The positive pole of the LED unit is connected to the positive pole of the output of the rectifier bridge, the negative pole is connected to the third terminal of the combined current source, the first terminal of the combined current source is connected to the positive pole of the rectifier bridge, and the second terminal is connected to the negative pole of the rectifier bridge.

[0041] Such as Figure 1a As shown, the LED unit includes at least one set of LEDs, an energy storage capacitor and a diode. The energy storage capacitor is connected in parallel to both ends of the LED, the cathode of the diode is connected to the anode of the LED, the anode of the diode is used a...

Embodiment 2

[0063] In the second embodiment, except that the circuit structure of the dynamic current source in the combined current source is different from that of the first embodiment, other circuit structures and working principles are the same, and will not be described again.

[0064] Such as Figure 4 As shown, the combined current source in this embodiment also includes an LED current source, a dynamic current source, a current detection circuit and a current detection resistor, and the specific structure is as follows:

[0065] Such as Figure 7 As shown, the current detection circuit includes a comparator COMP1-2, a first signal reference V1-2 and a switch S1-2. The LED current source includes a second transistor Q2-2, a second operational amplifier EA2-2 and a second reference signal V2-2. The LED current source and the detection resistor Rn-2 limit the current value of the third terminal of the combined current source. . The dynamic current source includes a third transist...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention provides a linear constant-current LED driving circuit compatible with an SCR light modulator. The LED driving circuit is powered by a mains supply, and the SCR light modulator is connected with the mains supply in series. The LED driving circuit comprises a rectifying bridge, an LED unit and a combined current source, wherein the LED unit at least comprises a group of LEDs, and the combined current source comprises three terminals; a positive electrode of the LED unit is connected with an output positive electrode of the rectifying bridge, and a negative electrode is connected with a third end of the combined current source; and a first end of the combined current source is connected with a positive electrode of the rectifying bridge, and a second end is connected with a negative electrode of the rectifying bridge. The LED driving circuit and an LED driving method have the advantages of effectively controlling a descending slope of mains supply current, avoids the SCR mis-turning-off phenomenon caused by self-resonance of the SCR light modulator, and improves the compatibility of a linear LED driving scheme matched with the SCR light modulator in power supply application.

Description

technical field [0001] The invention relates to a power supply circuit and a method, in particular to a linear constant current LED driving circuit and a method compatible with a thyristor dimmer. Background technique [0002] In the application of LED lighting to replace incandescent lamps, it is necessary to solve the problem of compatibility with traditional thyristor dimmers in many occasions. Different from the purely resistive load of incandescent lamps, LED lighting drivers have discontinuous demand for mains current, which causes the thyristor dimmer to be turned off by mistake when the current is intermittent, resulting in brightness of LED lamps. Jumping, flickering and other incompatibility issues. [0003] The linear constant current drive scheme is expanding its market share because of its simple circuit and low cost. [0004] Current linear constant current drive schemes compatible with TRIAC dimmers, such as figure 1 As shown, the mains power is connected t...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): H05B37/02
Inventor 邵蕴奇
Owner SHANGHAI LOOALL ELECTRONICS CO LTD
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com