A RGB LED Driving Structure and Signal Processing Based on Tone-to-Color Conversion

In order to solve the uncertainty of voice-to-color conversion in which one of the three voice features（loudness, tone, rhythm） is applied to control LED color, a linear conversion solution is proposed. And a chromaticity diagram is defined by using hue definition on hue-saturation-lightness（HSL） hue ring and the normalization of CIE xyY which is a color standard defined by International Commission on Illumination（CIE）. The chromaticity diagram shows a linear relation between pitch and color, which is referred to conversions of other physical parameters as well. Based on the solution, red（R）, green（G） and blue（B） LEDs, the driving structure of a conversion circuit is designed and set up. The results indicate that signal processing of tone-to-color conversion is effective, from 30 Hz to 3 kHz with a resolution of 10 Hz mapped to the chromaticity diagram.

Accelerated Luminous Depreciation Testing for LED Lighting Products

With the application of energy-saving, environmental and durable LED lighting products, the reliability testing has become a pivot point for the large scale industrialization and popularization. The paper briefly introduces two methods to be respectively applied in the accelerated depreciatinn lesting for the luminous flex of LED lighting products and the life of outdoor LED-driving power, which can sharply shorten the time for lifetime lest. providing references for the LED lighting products＇ reliability evaluation.

Design and implementation of a high precision and wide range adj ustable LED drive controller

This paper presents a novel high precision and wide range adjustable LED constant-current drive controller design.Compared with the traditional technique,the conventional mirror resistance is substituted by a MOSFET with fixed drain voltage,and a negative feedback amplifier is used to keep all mirror device voltages equal,so that the output current is precise and not affected by the load supply voltage.In addition,the electric property of the mirror MOSFET is optimized by a current subsection mirror（CSM） mechanism,thus ensuring a wide range of output current with high accuracy.A three-channel LED driver chip based on this project is designed and fabricated in the TSMC 0.6μm BCD process with a die area of 1.1×0.7 mm^2.Experimental results show that the proposed LED drive controller works well, and,as expected,the output current can be maintained from 5 to 60 mA.A relative current accuracy error of less than 1%and a maximal relative current matching error of 1.5%are successfully achieved.

Design and implementation of a high dimming ratio LED drive controller

This paper presents a high dimming ratio light emitting diode （LED） drive controller chip with digital mode dimming （DMD）. The chip is composed of a boost power converter and a dimming control block. A novel constant on time （COT） control strategy is proposed for boost converter to achieve high dimming ratio. In addition, a fast enough load transient response of the converter power stage ensures its high dimming ratio. The COT control circuit operates mainly based on two current-capacitor timers and a finite state machine （FSM）. The LED drive controller chip is designed and fabricated in 1.5μm bipolar CMOS-DMOS （BCD） process with a die area of 1.31 x 1.43 mm^2. Experimental results show that the proposed LED drive system works well. And, as expected, the minimum LED dimming on time of 1.0μs and the corresponding dimming ratio of 1000 ： 1 at 1 kHz dimming frequency are successfully achieved.