ScholarWorks@성균관대학교

초록

This paper introduces an adaptive seamless mode transition technique between noninverting buck–boost converter and LDO regulator for modern AMOLED display applications. Instead of PFM control, the system incorporates LDO operation under light-load conditions to overcome the inherent limitations of PFM control and maintains a clean output voltage, which directly affects display quality. By presetting an optimal control voltage and adaptively adjusting it through real-time feedback, the system ensures stable output and fast settling during mode transitions. To further enhance integration efficiency, the compensation capacitors and the error amplifier are shared across both operating modes, significantly reducing redundancy and minimizing silicon area overhead. Consequently, the proposed design achieves seamless transitions, improved light-load efficiency, and compact system integration. The chip was fabricated by 0.13-μm BCD process. The input voltage ranges from 2.4 to 4.9 V, while the output voltage is typically 2.8 V and programmable from 2.5 to 3.2 V. According to experimental results, the transition ripple remains around 5 mV or less with fast settling across the entire operating conditions, validating the effectiveness of the method.

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