Accurate PLL charge pump with matched up/down currents from Vds-

Details Accurate PLL charge pump with matched up/down currents from Vds- Accurate PLL charge pump with matched up/down currents from Vds-

1999-03-08

2000-09-26

Kim, Jung Ho

Miscellaneous active electrical nonlinear devices, circuits, and

Signal converting, shaping, or generating

Current driver

326 83, H03K 300

Patent

active

061247413

ABSTRACT:
A more accurate charge pump reduces phase error in a PLL. An UP input pulse causes a p-channel drive transistor to charge a filter capacitor on the output, while a down DN input pulse causes an n-channel drive transistor to discharge the output. The drive transistors are connected to power or ground through a supply transistor. The supply transistor is biased on in the linear region and is not switched off. The sources of the drive transistors are always driven by the supply transistors, preventing phase error from floating sources. The drive transistors are common-gate switches with their gates biased by a compensating bias generator. The p-channel drive transistor current variations with Vds are compensated by providing a similar current variation to the n-channel drive transistor. Thus the bias is adjusted to compensate for drain-source voltage changes that can cause the up and down currents from the drive transistors to mismatch. The drive transistors are switched on and off by the up and down input pulses by current sources that steer additional current through the supply transistors. The additional current raises the n-channel drive transistor source to turn off the down current. Additional current from a current source also lowers the p-channel drive transistor's source to turn it off. The same polarity and threshold are used for both up and down input pulses, further reducing phase error.

REFERENCES:
patent: 4331889 (1982-05-01), Parrish
patent: 5003197 (1991-03-01), Nojima et al.
patent: 5155384 (1992-10-01), Ruetz
patent: 5285114 (1994-02-01), Atriss et al.
patent: 5362990 (1994-11-01), Alvarez et al.
patent: 5412349 (1995-05-01), Young et al.
patent: 5422529 (1995-06-01), Lee
patent: 5502411 (1996-03-01), Matsuki et al.
patent: 5508660 (1996-04-01), Gersbach et al.
patent: 5532636 (1996-07-01), Mar et al.
patent: 5642082 (1997-06-01), Jefferson
patent: 5646563 (1997-07-01), Kuo
patent: 5663686 (1997-09-01), Tada
patent: 5734279 (1998-03-01), Bereza
patent: 5736880 (1998-04-01), Bruccoleri et al.
patent: 5767736 (1998-06-01), Lakshmikumar et al.

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