Differential charge pump

A method comprising:

• producing, by a first switching circuit, a first output (FILT);
• producing, by a second switching circuit, a second output (FILTN) and a third output (SENSEN);
• controlling, by a first amplifier and based on FILTN and SENSEN, a first current source electrically connected to a first port of the first switching circuit and a second current source electrically connected to the second switching circuit;
• and
• controlling, by a second amplifier and based on FILT and FILTN, a third current source electrically connected to a second port of the first switching circuit.

A phase locked loop comprising:

• a phase frequency detector arranged to produce a first output based on a reference signal and an oscillating signal;
• a differential charge pump comprising:
• a first switching circuit arranged to produce a second output (FILT) based on the first output;
• a second switching circuit arranged to produce a third output (FILTN) and a fourth output (SENSEN) based on the first output;
• a first current source electrically connected to a first port of the first switching circuit;
• a second current source electrically connected to a second port of the first switching circuit;
• a third current source electrically connected to the second switching circuit;
• a first amplifier arranged to control the second current source and the third current source based on FILTN and SENSEN;
• and
• a second amplifier arranged to control the first current source based on FILT and FILTN;
• and
• an oscillator arranged to produce the oscillating signal based on FILT and FILTN.