A CMOS low dropout regulator for internet of things

Abstract

With the growing demand of portable devices or the emergence of Internet-of-Things (IoT) applications, the push for small-size and ultra-low-power Low Dropout (LDO) Regulators becomes the key design agenda. Unfortunately, when approaching ultralow power, the transient performance metrics of the regulator are often significantly reduced. Moreover, the parasitic poles of regulator's devices, which are located at low frequencies, can lead to the instability issue. As such, these undesirable effects pose the serious design challenges in the context of ultra-low quiescent power design constraints. To tackle the stated problems, an ultra-low quiescent power capacitorless LDO regulator is proposed with employment of the transistor degeneration frequency compensation (TDFC) in the adaptive frequency compensation scheme. It can deliver a full loading current range from 0 to 100 mA and provide a 1 V output voltage from a 1.2 V power supply at a capacitive load of 100 pF whilst consuming only 407 nA for the entire regulator architecture. The total on-chip capacitance is 6.5 pF. On top of that, a distributed overshoot reduction (DOVSR) topology is also proposed to tackle the overshoot reduction problem under ultra-low quiescent circuit design. By incorporating the TDFC scheme and the feedforward biasing design, this results in reduced settling time and overshoot voltage with respect to that of the conventional circuit technique.