A phase locked loop with a charge pump circuit has increased stability and
phase margin. The charge pump circuit feeds back its voltage output to
generate a reference current. In one embodiment, the charge pump circuit
comprises a current generator responsive to a charge voltage that has
been output from the charge pump. The current generator generates a
reference current based on the charge voltage and a supply voltage. The
reference current may comprise a bootstrap current and an auxiliary
current. The charge pump circuit also comprises a current mirror that
generates a source current and a sink current that are substantially the
same as the reference current. The charge pump circuit further comprises
a charge voltage generator to generate the charge voltage based on the
source current and the sink current. A related method is also disclosed.
Other embodiments are provided, and each of the embodiments can be used
alone or in combination with one another.