RGB LED Backlight of Color Sequential Display with Precise Current-Balance Control Technique

摘要

This paper proposes a high efficiency and precise current balance circuit in parallel RGB Light Emitting Diodes (LED) channels for color filter-less panel display. The new technique not only enhances the current matching in each channel hut also reduces the requirement of device numbers and external resistors. The error percentage of all channel LED currents can kept within 0.1% when the channel voltage has a voltage variation (△V{sub}(CH)) around 1.1V. Furthermore, the proposed load dependent minimum drain voltage can effectively reduce the voltage drop across the precise current balance circuit. As a result, the efficiency of the LED driver can be improved.