An Energy Efficient V Generator With Fast Ramp-Up Time for Mobile DRAM

• Published in: IEEE journal of solid-state circuits 2011-06, Vol.46 (6), p.1488-1494
• Main Authors: Kim, Kyu-Young, Kim, Yonghwan, Lee, Doo-Chan, Kang, Yu-Ri, Kim, Hoonki, Kim, Soo-Won, Park, Jongsun
• Format: Article
• Language: English
• Subjects: Charge pump; Charge pumps; Clocks; Energy consumption; Generators; mobile DRAM; Random access memory; Time frequency analysis; V_{\rm PP} generator; voltage controlled oscillator; voltage doubler; Voltage-controlled oscillators
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2011.2128170

An energy efficient V PP generator with fast ramp-up time for mobile DRAM is presented in this paper. Instead of using a fixed pumping clock frequency as in the conventional V PP generator, the proposed V PP generator adopts a voltage-controlled oscillator (VCO) and uses variable pumping frequencies to improve the ramp-up time as well as energy efficiency. Numerical results show that the VCO based V PP generators achieve energy savings of up to 34% with 40% improvement on ramp-up time when compared to the conventional ring oscillator (RO) based design. Our proposed V PP generator, which uses a three-stage voltage doubler as a charge pump, was implemented and fabricated in CMOS 0.13 μm process. The V PP generator chip's core occupies 0.6 mm 2 area and consumes 1162 nJ (average power of 47.8 mW during 24 μs ramp-up time) while generating 3.0 V output voltage with 1.0 nF load capacitor, 2.0 mA current load and 1.2 V supply voltage.