PLL circuit

Details PLL circuit PLL circuit

1996-09-27

1999-08-24

Callahan, Timothy P.

Miscellaneous active electrical nonlinear devices, circuits, and

Signal converting, shaping, or generating

Synchronizing

327158, 327 12, 327 7, 331 17, 331 34, H03L 7089, H03L 7099

Patent

active

059429267

ABSTRACT:
A PLL circuit is disclosed which can achieve a locked state in a short time. The PLL circuit has a phase comparator, a loop filter and a voltage controlled oscillator. The phase comparator is provided with frequency adjusting (or matching) circuits that are operative to charge the loop filter when it is detected that an oscillation frequency of the voltage controlled oscillator is lower than a frequency of an input signal, so as to increase the oscillation frequency of the voltage controlled oscillator, until it is detected that an oscillation frequency of the voltage controlled oscillator is higher than the frequency of the input signal. Similarly, the loop filter is discharged when it is detected that an oscillation frequency of the voltage controlled oscillator is higher than a frequency of an input signal, so as to decrease the oscillation frequency of the voltage controlled oscillator, until it is detected that an oscillation frequency of the voltage controlled oscillator is lower than the frequency of the input signal. The phase comparator is further provided with phase adjusting (or matching) circuits for adjusting a phase of an output of the voltage controlled oscillator to a phase of the input signal after the oscillator frequency of the voltage controlled oscillator is adjusted to the frequency of the input signal. Thus, a time required to adjust the oscillation frequency of the voltage controlled oscillator can be considerably reduced.

REFERENCES:
patent: 4451794 (1984-05-01), Yamada
patent: 4803705 (1989-02-01), Gillingham et al.
patent: 4837643 (1989-06-01), Tierney, III
patent: 5072195 (1991-12-01), Graham et al.
patent: 5144156 (1992-09-01), Kawasaki
patent: 5220294 (1993-06-01), Ichikawa
patent: 5297173 (1994-03-01), Hikmet et al.
patent: 5315186 (1994-05-01), Baker
patent: 5332930 (1994-07-01), Volk
patent: 5371425 (1994-12-01), Rogers
patent: 5463353 (1995-10-01), Countryman et al.
patent: 5475326 (1995-12-01), Masuda
patent: 5508660 (1996-04-01), Gersbach et al.
patent: 5563553 (1996-10-01), Jackson
patent: 5661419 (1997-08-01), Bhagwan
Toshihiko Moro, "Transistor Art", pp. 270-271, vol. 31, No. 356, May 1994 (in Japanese, accompanied with English translation).

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