Adaptive light emitting diode dimming driving circuit

Abstract

An adaptive LED dimming driving circuit is disclosed, wherein its control module is disposed with a first resistor, a second resistor, a retainer, a third resistor and a fourth resistor. When the control module receives an input voltage, the retainer is driven to output a retaining current Ihold to the second resistor, thereby ensuring normal dimming. The first resistor and the third resistor detect the input voltage so that when an input current Iin satisfies a correlation Iin=Ihold+ILED, the retaining current has the minimum value to increase work efficiency during the LED that is dimmed to the maximum intensity. When the input voltage is too low, the reference level is reduced to prevent the LED from generating twinkling. The fourth resistor detects the voltage energy of the LED. Therefore, when the voltage energy is changed, a high-low-voltage compensation is performed to achieve a constant power state.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 101149726 filed in Taiwan, R.O.C. on Dec. 25, 2012, the entire contents of which are hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The invention relates to a technical field of light emitting diode (LED) power equipment, and more particularly to an adaptive LED dimming driving circuit supporting TRI-electrode AC switch (TRIAC) that flexibly compensates outputted driving electricity by means of detecting the inputted electricity ripple voltage difference real-time so that the work efficiency of whole circuit can be improved, and the twinkling problem on LEDs can also be prevented.[0004]2. Description of the Related Art[0005]Currently, the driving circuit of an LED lamp is to linearly regulate the LED brightness and is accomplished by means of switching an input voltage conduction angle thr...

AI Technical Summary

Benefits of technology

The present invention provides an adaptive LED dimming driving circuit using linear regulation to prevent LED twinkling and maintain TRIAC dimming feature. The circuit includes a control module with a regulator, a sensing resistor, and a retainer to retain the LED at maximum brightness. The control chip regulates the driving current based on the sensing value, which is fed back to the chip after the sensing resistor senses the driving current. The circuit does not utilize transformers or inductors to switch PWM signals, which reduces costs and prevents power consumption and heat energy issues. The LED brightness can be adjusted by reducing the retainer output current, and the control chip detects the ripple value of the input voltage to prevent LED twinkling at low brightness levels. The circuit improves overall circuit efficiency, power factor, and product service life.

Problems solved by technology

Consequently, the energy conversion efficiency will be seriously damaged.

Accordingly, the foregoing dimming method may affect the whole circuit efficiency due to different changes of voltages and current, and the problem of inaccurately dimming effect may occur.

Moreover, the circuit architecture utilizing the transformer or the inductor to realize the switching of duty ratio of PWM signals has problems of electromagnetic interference (EMI) and twinkling.

At this time, if safety components are increased, the work efficiency of the whole circuit is reduced to cause non-practicality.

It may still work due to retaining current to form high idle work consumption since the LED is regulated to reach the maximum light emitting brightness.

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