论文信息 - A digital multiplexing and real-time refresh dimming control circuit used in LED driver for multiple LED strings

A digital multiplexing and real-time refresh dimming control circuit used in LED driver for multiple LED strings

This paper presents a digital dimming control circuit used in a light-emitting diode (LED) driver, allowing it to dim multiple LED strings with only two input ports which receive serial data accompanied with synchronous clock. A multiplexing technique is used to simplify the control circuit, using one DAC to transfer all the dimming messages for each string, and a real-time refresh technique is used to make the transferred dimming voltage keep a high accuracy all the time. The circuit is friendly compatible with the linear current regulator and pulsewidth modulation (PWM) dimming methods. To get a precise dimming control, we build a 10-bit segment R-2R DAC. The simulation results show the dimming voltages for each LED string keep the errors less than 0.5LSB compared with the designed voltages.

[1] Ralf Wunderlich,et al. A Dimmable LED Driver With Resistive DAC Feedback Control for Adaptive Voltage Regulation , 2015, IEEE Transactions on Industry Applications.

[2] K. I. Hwu,et al. A Dimmable LED Driver Based on Current Balancing Transformer With Magnetizing Energy Recycling Considered , 2014, Journal of Display Technology.

[3] Hoi Lee,et al. A 40V 10W 93%-efficiency current-accuracy-enhanced dimmable LED driver with adaptive timing difference compensation for solid-state lighting applications , 2013, Proceedings of the IEEE 2013 Custom Integrated Circuits Conference.

[4] Huang-Jen Chiu,et al. A High-Efficiency Dimmable LED Driver for Low-Power Lighting Applications , 2010, IEEE Transactions on Industrial Electronics.