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http://dx.doi.org/10.6109/jkiice.2016.20.6.1154

Fast-Transient Digital LDO Regulator With Binary-Weighted Current Control  

Woo, Ki-Chan (Department of Semiconductor Engineering, Chungbuk National University)
Sim, Jae-Hyeon (Silliconworks)
Kim, Tae-Woo (Department of Semiconductor Engineering, Chungbuk National University)
Hwang, Seon-Kwang (Department of Semiconductor Engineering, Chungbuk National University)
Yang, Byung-Do (Department of Electronics Engineering, Chungbuk National University)
Publication Information
Journal of the Korea Institute of Information and Communication Engineering / v.20, no.6, 2016 , pp. 1154-1162 More about this Journal
Abstract
This paper proposes a fast-transient digital LDO(Low dropout) regulator with binary-weighted current control technique. Conventional digital LDO takes a long time to stabilize the output voltage, because it controls the amount of current step by step, thus ringing problem is generated. Binary-weighted current control technique rapidly stabilizes output voltage by removing the ringing problem. When output voltage reliably reaches the target voltage, It added the FRZ mode(Freeze) to stop the operation of digital LDO. The proposed fast response digital LDO is used with a slow response DC-DC converter in the system which rapidly changes output voltage. The proposed digital controller circuit area was reduced by 56% compared to conventional bidirectional shift register, and the ripple voltage was reduced by 87%. A chip was implemented with a $0.18{\mu}F$ CMOS process. The settling time is $3.1{\mu}F$ and the voltage ripple is 6.2mV when $1{\mu}F$ output capacitor is used.
Keywords
Multiple current; digital LDO; regulator; ripple;
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