Journal of the Korea Institute of Information and Communication Engineering (한국정보통신학회논문지)

The Korea Institute of Information and Commucation Engineering (한국정보통신학회)
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A PLL with high-speed operating discrete loop filter

고속에서 동작하는 이산 루프필터를 가진 PLL

  • An, Seong-Jin (Department of Electronic Engineering, Pukyong National University) ;
  • Choi, Young-Shig (Department of Electronic Engineering, Pukyong National University)
  • Received : 2016.07.21
  • Accepted : 2016.08.10
  • Published : 2016.12.31
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Abstract

In this paper, the proposed small size PLL works stable with the discrete loop filter which is controlled by voltage controlled oscillator's output signal. A switch controlled loop filter is introduced into the proposed PLL instead of a conventional $2^{nd}$-order loop filter. Those three switches are controlled by the very high frequency output signal of voltage controlled oscillator. The switches are also controlled by UP/DN signals and 'on/off' depending the presence of UP/DN signals. A negative feedback functioned capacitor with a switch does make it possible to integrate the PLL into a single chip. The proposed PLL works stably even though a total of small 180pF capacitor used in the discrete loop filter. The proposed PLL has been designed with a 1.8V supply voltage, 0.18um multi - metal and multi - poly layer CMOS process and proved by Hspice simulation.

본 논문에서는 기존 위상고정루프의 아날로그 루프 필터 형태와 달리 전압제어발진기의 출력 신호로 동작하는 이산 루프 필터를 사용하여 크기는 작으면서 안정하게 동작하는 위상고정루프를 제안하였다. 기존의 위상고정루프에 2차 루프필터 대신 스위치 제어 루프필터를 사용하였다. 스위치는 전압제어발진기위의 고속의 출력 신호에 의해 제어된다. 총 3개의 스위치는 UP/DN 신호를 통하여 제어되고, UP/DN 신호에 따라 스위치가 'on/off'를 반복한다. 샘플링과 부궤환 역할을 하는 스위치와 결합된 작은 크기의 커패시터로 하나의 칩으로 집적화가 가능하다. 제안된 위상고정루프의 이산 루프 필터에 사용된 커패시터 값은 총 180pF로 아주 작은 크기임에도 불구하고 안정적으로 동작한다. 제안된 위상고정루프는 1.8V의 공급전압에서 0.18um CMOS 공정의 파라미터를 이용하여 Hspice로 시뮬레이션을 수행하고, 동작을 검증하였다.

Keywords

References

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