Method for driving array-type alternating current-light-emitting diode (AC-LED) chips

Abstract

The invention provides a method for driving array-type alternating current-light-emitting diode (AC-LED) chips. A driving voltage is provided; the driving voltage performs periodical pulsation change surrounding the corresponding average value within a certain range, and has a driving wave form; at any time, the driving voltage value is always not less than the voltage at an LED threshold opening terminal, and is not larger than the LED peak terminal voltage; and the driving voltage is utilized to drive an LED light-emitting unit to operate. The method provided by the invention has the beneficial effects of simple structure, less electronic components, small circuit volume and long service life; and the light source continuously emits light and the emitted light approaches to the natural light.

Description

A kind of driving method of array type AC-LED chip technical field The invention belongs to the technical field of AC-LEDs, and in particular relates to a driving method for arrayed AC-LED chips. Background technique So far, although the development of LED constant DC power supply has gone through the first stage of simple constant current-non-isolated type and the second stage of constant current-isolated type, and is entering the PF correction-constant current constant voltage-isolated type In the third stage, its inherent shortcomings in terms of life, power supply size, and price cannot be significantly improved. For this reason, a new type of technology named AC-driven high-voltage array LED chip (array AC-LED chip) has been proposed and developed rapidly in the past five years. The basic concept of the array AC-LED is not to use additional (other than the chip) AC-DC conversion and rectification circuits, but to directly drive the LEDs with AC power by using a curr...

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Problems solved by technology

However, AC-LED has a potential fundamental weakness: since the operating current of AC-LED is much higher than the corresponding DC-LED operating current of the same brightness most of the time when the device is in the state of light emission, the peak value reaches four times the difference The internal quantum efficiency of the AC-LED device itself is lower than that of the DC-LED with the same luminous brightness due to the limitation of the droop effect. The reason for the Droop effect is more complicated and depends on the polarization effect including the nitride material. Intermittent recombination (Augercombination), diode junction temperature (junction temperature), indium atom clustering effect (In-rich) and other materials and the influence of LED structure, the internal quantum efficiency of AC-LED is higher than that of constant DC LED with the same power output It is about 15-20% lower, and the driving voltage in AC-LEDs changes periodically, so the driving current and light intensity show pulse-changing characteristics, and the duty cycle is only about 60%.

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