Improved transient response capacitor less low dropout regulator employing adaptive bias and bulk modulation

This paper presents a low quiescent current, fast settling time, and adaptively biased capacitor less lowdropout (LDO) regulator. The topology involves a segmented pass transistor with bulk modulation and adaptivelybiased current control stages to improve the transient performance. The bulk modulation of the pass transistor assistsin fast settling of the output voltage. The frequency compensation makes the LDO voltage regulator stable adaptivelyover load current transitions. In addition, the biasing stage is designed such that it adapts to the load transitionswhile consuming the quiescent current abstemiously. This arrangement further improves settling time to be within 1 µswhile restricting undershoot/overshoot to 171 mV/82 mV for a load current transition between 0 and 100 mA with loadcapacitor of 40 pF. The LDO regulator is designed using 0.18 µm UMC CMOS process by consuming 1.5 µA quiescentcurrent at no loads

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Kang YH, Kim JK, Hwang SW, High-voltage analog system for a mobile NAND flash. IEEE J Solid-St Circ 2008; 43: 507-517.
López T, Alarcón E. Power MOSFET technology roadmap toward high power density voltage regulators for nextgeneration computer processors. IEEE T Power Electr 2012; 27: 2193-2203.
Peng SY, Liu LH, Chang PK, Wang TY, Li HY. A power-efficient reconfigurable output-capacitor-less low dropout regulator for low-power analog sensing front-end. IEEE T Circuits-I 2017; 64: 1318-1327.
Huang M, Lu Y, Martins RP. An output-capacitor-free analog-assisted digital low-dropout regulator with tri-loop control. ISSCC Dig Tech Pap I 2017; 342-343.
Lim J, Lee J, Jung S. SI/PI Co-simulation including voltage regulating circuitry for high-performance multi-chip package. Int Symp Elec Compat 2014; 366-369.
Milliken RJ, Silva-Martinez J, Sanchez-Sinencio E. Full on-chip CMOS low-dropout voltage regulator. IEEE T Circuits-I 2007; 54: 1879-1890.
Man TY, Leung KN, Leung CY, Mok PKT, Chan M. Development of single-transistor-control LDO based on flipped voltage follower for SoC. IEEE T Circuits-I 2008; 55: 1392-1401.
Hazucha P, Karnik T, Bloechel BA, Parsons C, Finan D,Borkar S. Area-efficient linear regulator with ultra-fast load regulation. IEEE J Solid-St Circ 2005; 40: 933-940.
Chun Ka, Mok PKT. Pole-zero tracking frequency compensation for low dropout regulator. ISCAS 2002: IEEE International Symposium On Circuits And Systems - Proceedings 2002; 4: 735-738.
Man TY, Mok PKT , Chan M. A high slew-rate push–pull output amplifier for low-quiescent current low-dropout regulators with transient-response improvement. IEEE T Circuits-II 2007; 54: 755-759.
Chong S, Chan PK. A 0.9µA quiescent current output-capacitorless LDO regulator with adaptive power transistors in 65-nm CMOS. IEEE T Circuits-I 2013; 60: 1072-1081.
Maity A, Patra A. Trade offs aware design procedure for an adaptively biased capacitorless low dropout regulator using nested miller compensation. IEEE T Power Electr 2016; 31: 369-380.
Keikhosravy K , Mirabbasi S. A 0.13µm CMOS low-power capacitor-less LDO regulator using bulk-modulation technique. IEEE T Circuits-I 2014; 61: 3105-3114.
Saberkari A, Qaraqanabadi F, Shirmohammadli V, Martínez H, Alarcon E. Output-capacitorless segmented lowdropout voltage regulator with controlled pass transistors. Int J Circ Theor App 2016; 44: 460-475.
Shirmohammadli V, Saberkari A, Martínez-García H, Alarcón-Cot E. Enhancing the performance of outputcapacitorless LDO regulators by pass-transistor segmentation. ISCAS 2016: IEEE International Symposium On Circuits And Systems – Proceeding 2016; 490-493.
Or PY, Leung KN. An output-capacitorless low-dropout regulator with direct voltage-spike detection. IEEE J Solid-St Circ 2010; 45: 458-466.
Guo J , Leung KN. A 6µw chip-area-efficient output-capacitorless LDO in 90-nm CMOS technology. IEEE J Solid-St Circ 2010; 45: 1896-1905.
Zhan C, Ki WH. An output-capacitor-free adaptively biased low-dropout regulator with subthreshold undershootreduction for SoC. IEEE T Circuits-I 2012; 59: 1119-1131.