LED drive circuit structure with separated switching tube

Abstract

The invention discloses an LED drive circuit structure with a separated switching tube. The LED drive circuit structure with the separated switching tube comprises a series connection topological structure, an input voltage detection unit, a load current detection unit and a control unit. The series connection topological structure comprises one or more series connection drive modules. The input voltage detection unit and the load current detection unit are respectively connected with the control unit. The input voltage detection unit is used for detecting the input voltage of the series connection topological structure, and outputting information of the input voltage to the control unit. The load current detection unit is used for detecting a load current of each series connection drive module, and outputting information of the load currents to the control unit. The control unit is connected with the grid electrode of an MOS tube in each series connection drive module, and is used for controlling the voltage of the grid electrode of each MOS tube according to the information of the input voltage and the information of the load currents, so that the load currents are in direct proportion to the input voltage when LED strands are conductive. By means of the LED drive circuit structure, drive efficiency is improved, a power factor of a circuit is improved, and the compatibility between the circuit and a TRIAC light modulator is improved.

Description

Technical field [0001] The present invention relates to the field of LED (light emitting diode) lighting, in particular to a switch tube separated LED drive circuit structure. Background technique [0002] LED chips are widely used in the field of new energy-saving light sources with their high efficiency, high integration, and long life. In the LED light source, power drive is a key technology. Due to the high integration and low cost requirements for LED applications, LED drive solutions without energy storage devices such as inductors and capacitors have taken up an increasing share of the market, and will become mainstream LED drive solutions in future applications. In this type of driving scheme, the control IC controls the number of LEDs through which the actual conduction current passes by adjusting the gate voltage of the LED channel switch MOS tube to compensate for the excessive conduction current to the input voltage caused by the nonlinearity of the LED. Sensitive, ...

AI Technical Summary

Problems solved by technology

[0007] 1. The driving efficiency is not high

Due to the large voltage drop of the MOS tube at some operating points, the driving efficiency is difficult to reach more than 90%, which makes it difficult for this type of drive to compete with the switching power supply drive in terms of efficiency.

[0008] 2. The power factor is not high

[0009] 3. Harmonic interference

This problem is more prominent than point 2

[0010] 4. Mismatch with some TRIAC (three-terminal bidirectional AC switch) dimming equipment

Since the on and off of the TRIAC is controlled by the conduction current, when the conduction current is excessively fed back, the TRIAC will form a bistable state at some operating points. There will be flickering in the light, such flickering is unacceptable to customers in the application

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