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Electronics and Telecommunications Research Institute (한국전자통신연구원)
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Accurate Tunable-Gain 1/x Circuit Using Capacitor Charging Scheme

  • Yang, Byung-Do (Department of Electronics Engineering, Chungbuk National University) ;
  • Heo, Seo Weon (School of Electronic & Electrical Engineering, Hongik University)
  • Received : 2014.05.13
  • Accepted : 2015.01.02
  • Published : 2015.10.01
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Abstract

This paper proposes an accurate tunable-gain 1/x circuit. The output voltage of the 1/x circuit is generated by using a capacitor charging time that is inversely proportional to the input voltage. The output voltage is independent of the process parameters, because the output voltage depends on the ratios of the capacitors, resistors, and current mirrors. The voltage gain of the 1/x circuit is tuned by a 10-bit digital code. The 1/x circuit was fabricated using a $0.18{\mu}m$ CMOS process. Its core area is $0.011mm^2$ ($144{\mu}m{\times}78{\mu}m$), and it consumes $278{\mu}W$ at $V_{DD}=1.8V$ and $f_{CLK}=1MHz$. Its error is within 1.7% at $V_{IN}=0.05V$ to 1 V.

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References

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