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Non-strobe non-isolated LED constant-current driving circuit

A constant current drive, non-isolated technology, applied in the direction of lamp circuit layout, electric light source, lighting devices, etc., can solve the problems of stroboscopic, failure to meet product certification requirements, and periodic current

Inactive Publication Date: 2014-10-08
ZHEJIANG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The average current output by the constant current drive circuit is stable, but there is a periodic current, and there is a flicker problem: in the power frequency cycle, when the input voltage is too low, the LED load will be off for a period of time, which will cause the LED Light output contains 100Hz strobe
The output current of the constant current drive circuit is constant, but the PF (power factor) is only about 40%, which does not meet the product certification requirements

Method used

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  • Non-strobe non-isolated LED constant-current driving circuit
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Embodiment Construction

[0019] In order to describe the present invention more specifically, the technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0020] A flicker-free non-isolated LED constant current drive circuit such as image 3 As shown, it includes: AC input source, rectifier bridge DB, capacitor C1, constant current drive unit 11, constant current drive unit 12 and LED load (consisting of multiple LEDs connected in series). Among them: the two ends of the AC input source are connected to the AC side of the rectifier bridge DB; the positive pole of the DC side of the rectifier bridge DB is connected to the anode of the LED load, the positive terminal of the capacitor C1, the a terminal of the constant current drive unit 11 and the terminal of the constant current drive unit 12 a terminal; the cathode of the LED load is connected to the b terminal of the constant current drive unit 11; the c t...

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Abstract

The invention discloses a non-strobe non-isolated LED constant-current driving circuit which comprises an alternating-current source, a rectifier bridge, a capacitor and two constant-current driving units. The alternating-current side of the rectifier bridge is connected with the alternating-current source, the direct-current side of the rectifier bridge is connected with an anode of an LED, one end of the capacitor and the power ends of the two constant-current driving units, and the negative end of the direct-current side is grounded. A cathode of the LED is connected with the input end of the first constant-current driving unit, the output end of the first constant-current driving unit is connected with the other end of the capacitor and the input end of the second constant-current driving unit, and the output end of the second constant-current driving unit is grounded. According to the LED constant-current driving circuit, the charging current of an AC input source to the capacitor is controlled to be constant, the circuit is made to achieve the effect that an LED load dose not have strobe, meanwhile, above 80 percent of power factors can be achieved, and therefore the product certification requirements are met.

Description

technical field [0001] The invention belongs to the technical field of LED constant current drive, and in particular relates to a flicker-free and non-isolated LED constant current drive circuit. Background technique [0002] LED (Light Emitting Diode, Light Emitting Diode) is a typical current-mode device, and its ideal power supply mode is constant current power supply, which requires high stability of working current. The non-isolated linear constant current LED drive circuit is favored by the market because of its simple peripheral circuit and simple control method. The average current output by the constant current drive circuit is stable, but there is a periodic current, and there is a flicker problem: in the power frequency cycle, when the input voltage is too low, the LED load will be off for a period of time, which will cause the LED The light output contains a 100Hz strobe. Light flickering at this frequency will not only cause visual nerve fatigue and endanger h...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05B37/02
Inventor 吴旭烽冷亚辉何乐年奚剑雄朱勤为黄飞明
Owner ZHEJIANG UNIV
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