Miller Capacitor with Wide Input Range and Its Application to PLL Loop Filter

Masahiro YOSHIOKA  Nobuo FUJII  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E89-A   No.12   pp.3685-3692
Publication Date: 2006/12/01
Online ISSN: 1745-1337
DOI: 10.1093/ietfec/e89-a.12.3685
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Analog Signal Processing
Miller capacitor,  PLL,  low frequency filter,  loop filter,  

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This paper proposes a Miller capacitor which has a wide input signal range. By discharging the charge of the capacitor connected between the input and output terminals of an amplifier before the output voltage of the amplifier exceeds its maximum range, the amplifier always operates in the active region and the Miller operation can be guaranteed. Thus a large value capacitor with a wide dynamic operation range can be realized using a small value capacitor. The Miller capacitor proposed in this paper is applied to a loop filter of phase locked loop (PLL) circuit that requires a large value capacitor to realize a low cutoff frequency. SPICE simulation of the PLL circuit using the Miller capacitor confirms the operation of the Miller capacitor and shows good performances that are similar to those obtained using a passive capacitor of a large value.