Digitally-assisted constant-on-time dynamic-biasing technique for bandwidth and slew-rate enhancement in ultra-low-power low-dropout regulator

A digitally-assisted constant-on-time dynamic-biasing (COT-DB) technique has been proposed to enable significant enhancement in dynamic performances, while the average current consumption can be kept to ultralow level. This dynamic-biasing technique has a predefined magnitude and duration on biasing current boost, which is beneficial to estimate power budget in systems with finite energy source. The proposed technique has been applied to a low-dropout regulator (LDO) to demonstrate the effectiveness. Experimental results show that significant improvements in settling times during load-transients and line-transients are as much as 880x, while the current consumption is only 1.02A. In fact, for the same dynamic performances, the average current consumption of LDO with COT-DB technique can be as low as 0.39% of the LDO with heavy static biasing. The digitally-assisted implementation of the technique also allows robust augmentation of the technique onto almost all analog systems. Copyright (c) 2015 John Wiley & Sons, Ltd.