or the dummy switch and switch 620 to reach vccs 650 or vccs 640 on the other hand the output of the current source 605 also needs to pass through two switches 615 and 690 to reach vccs 650 the current source 610 therefore sees exactly the same load as the current source 605 does the performance of the current regulation therefore will be very good for those with ordinary skill in the art the method taught by the current invention can be easily applied to other circuit configurations for example the roles of current sink and current source can be swapped as demonstrated in an embodiment shown in fig7 here a regulated current source 710 is used to generate a regulated positive i e out flowing current a switch 720 controlled by the up signal is used to enable the positive current to flow out to the loop filter 750 on the other hand a reference current sink 730 of magnitude iref is used to generate a reference negative i e in flowing current a switch 740 controlled by the dn signal is used to enable the negative current to flow in from the loop filter 750 the loop filter generates two outputs vc and vr vc is the main output of the loop filter 750 and is provided to a vco not shown in the figure to control its output frequency vr is obtained from vc using a low.