A phase locked loop includes a differential charge pump to cancel static phase error and reduce sensitivity to noise. The differential charge pump comprises two substantially identical single-ended charge pumps so that under locked condition, changes in voltage at the charge pumps' output terminals are...http://www.google.fr/patents/US6011822?utm_source=gb-gplus-shareBrevet US6011822 - Differential charge pump based phase locked loop or delay locked loop
Differential charge pump based phase locked loop or delay locked loop
