Phase-locked loop circuit with current-pulse injection for improving linearity

A phase-locked loop for producing an output signal, the phase-locked loop comprising:

• a first circuit operable to produce a first signal that represents a phase difference between a feedback signal and a reference signal;
• and
• a second circuit coupled to the first circuit, the second circuit operable to produce a second signal, the second signal being controlled to vary over time, and to combine the second signal with the first signal to produce a control signal having an instantaneous value substantially equal to zero.

A phase-locked loop for producing an output signal, comprising:

• a first circuit operable to produce a first signal characterizing a phase difference between a feedback signal and a reference signal;
• and
• a second circuit coupled to the first circuit, the second circuit operable to produce a second signal having a rising edge corresponding to a rising edge of the feedback signal, the second circuit further operable to couple the second signal to the first signal to produce a control signal having an instantaneous value substantially equal to zero.

A phase-locked loop for producing an output signal, comprising:

• a first circuit operable to produce a first signal characterizing a phase difference between a feedback signal and a reference signal;
• and
• a second circuit coupled to the first circuit, the second circuit operable to produce a second signal having a falling edge corresponding to a rising edge of the feedback signal, the second circuit further operable to couple the second signal to the first signal to produce a control signal having an instantaneous value substantially equal to zero.

A phase-locked loop for producing an output signal, comprising:

• a first circuit operable to produce a first signal characterizing a phase difference between a feedback signal and a reference signal;
• and
• a second circuit coupled to the first circuit, the second circuit operable to produce a second signal, the second circuit further operable to couple the second signal to the first signal to produce a control signal having an instantaneous value substantially equal to zero, the second circuit further comprising a current source and a switch operable to transition between conducting and non-conducting states, the switch further operable to couple the current source to ground when in the conducting state.