Design of a capacitor-less adaptively biased low dropout regulator using recycling folded cascode amplifier

This paper starts with a comprehensive analysis of the trade-offs among various performance parameters in conventional adaptively biased low dropout regulator (AB-LDO) and then proposes a new structure of output capacitor-less AB-LDO, employing recycling-folded-cascode(RFC) amplifier, to optimize the different trade-offs. With this special structure, the proposed AB-LDO finally achieves faster dynamic response, better linear and load regulation without increasing power consumption. In addition, cascode compensation is employed to bring a wider load range while ensuring loop stability. Finally, the proposed AB-LDO is implemented in 0.18μ m CMOS process and experimental results show that a low quiescent current (10–50.25μA), good load regulation of 0.48 mV/mA, undershoot of 92 mV and overshoot of 86 mV with high current efficiency of 99.95% have been achieved.