T22.1 - An Ultra Compact RGB LED Driver with Only One Off-Chip Component, 97.25% Peak Efficiency, and Nearly Full-Range Color Gamut Coverage

The proliferation of intelligent electric vehicles imposes stringent demands on energy efficiency, integration, and reliability for on-board LED drivers, especially in RGB multi-color applications (e.g., automotive ambient lighting) requiring precise color mixing. Conventional LDO or DC-DC buck-boost solutions cannot simultaneously achieve high efficiency and high integration. This paper presents a highly integrated 3-switch RGB LED driver that requires only one off-chip inductor. Its topology merges DC-DC converter switches with RGB channel control switches, reducing switching losses and enhancing integration. The proposed design ensures robust operation against input voltage variation. An integration-comparison control scheme enables stable regulation of RGB color ratios. The driver maintains high efficiency across a wide color gamut and offers an efficiency–color gamut trade-off, enabling expanded gamut coverage at an acceptable efficiency cost. Fabricated in a 180nm CMOS process, the prototype IC achieves a peak efficiency of 97.08% under 5V input with white-light output, demonstrating its potential for energy-efficient, space-constrained automotive LED applications.