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Auto-excitation type LED driver

A LED driver, self-excited technology, applied in the field of power supply and LED drive, can solve the problems of unfavorable application promotion, high cost, complicated circuit, etc., and achieve the effect of low cost, high work efficiency and simple circuit

Inactive Publication Date: 2008-07-16
KUNMING ZHIXING SCI & TECH DEV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, most of the existing high-efficiency LED (light-emitting diode) drivers use a large loop current negative feedback method to provide stable operating current for the LED (light-emitting diode). The circuit is complex and the cost is too high, which is not conducive to the application and promotion of LED (light-emitting diode) lighting.

Method used

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  • Auto-excitation type LED driver
  • Auto-excitation type LED driver
  • Auto-excitation type LED driver

Examples

Experimental program
Comparison scheme
Effect test

specific Embodiment approach 1

[0026] The circuit structure of the specific embodiment 1 is a step-down working mode, and the input voltage must be greater than a certain value of the conduction voltage of the LED string to make it work normally, and the voltage obtained after the rectification of the AC mains is between zero and the maximum value Continuously changing voltage, when the number of LEDs in the LED string is large, it is necessary to use a filter capacitor C13 with a large capacity, so that the power factor of the driver is reduced. The LED driver that can be boosted or bucked can use a smaller filter capacitor C13 to obtain a higher power factor because it no longer requires that the input voltage must be greater than a certain value of the conduction voltage of the LED string to work.

specific Embodiment approach 3

[0027] After adjusting the output mode of the circuit in Embodiment 1, the boosted LED driver shown in Figure 4 is formed. The initial conduction voltage of the LED string must be greater than the maximum value of the input voltage, and it can also use a smaller filter capacitor C13 to obtain a higher voltage. power factor.

specific Embodiment approach 4

[0028] Figure 5 shows a high-precision constant current application circuit of the present invention, which differs from Embodiment 1 in that an independent energy storage inductance L21 is used, and the transformer T21 is only used for feedback oscillation. The primary winding N21 of the primary winding N21 is discharged through the resistor R23, the freewheeling diode D22, and the energy storage inductor L21 is discharged through the freewheeling diode D21 and the LED string. The resistance value of the resistor R23 is properly selected so that the discharge time of the primary winding N21 of the transformer T21 is much shorter than The discharge time of the energy storage inductor L21, when the discharge of the primary winding N21 of T21 ends, the transistor Q21 quickly turns into a saturated conduction state, at this time, the energy storage inductor L21 passes through the freewheeling diode D21, and the discharge current of the LED string only drops slightly It begins to i...

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Abstract

The invention discloses a self-excited LED (Light Emitting Diode) driver which consists of a transistor self-excited switching oscillator 2 and a current control circuit 3, and is provided with a DC power input end and a drive output end. The current control circuit 3 is used to limit the maximum current across the switching transistor of the self-excited switching oscillator in a saturated conduction state so as to provide constant drive output current or power, making all the driven LEDs shine steady.

Description

Technical field: [0001] The invention belongs to the technical field of LED (light-emitting diode) driving, and also belongs to the field of power supply technology. Background technique: [0002] The conductive characteristics of LED (light-emitting diode) are similar to those of ordinary diodes. They are forward-conducting, reverse-phase cut-off, and emit light when they are forward-conducting. increase, resulting in damage to the light-emitting diode, in order to ensure the stable operation of the light-emitting diode, usually using a constant current or constant power drive. [0003] At present, most of the existing high-efficiency LED (light-emitting diode) drivers use a large loop current negative feedback method to provide stable operating current for the LED (light-emitting diode). The circuit is complex and the cost is too high, which is not conducive to the application and promotion of LED (light-emitting diode) lighting. . Invention content: [0004] The prese...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05B37/02
Inventor 戴清平
Owner KUNMING ZHIXING SCI & TECH DEV