Linearization technique for phase locked loops employing differential charge pump circuitry
First Claim
1. A differential linear phase locked loop comprises:
- phase and frequency detection module operably coupled to produce a differential charge up signal, a differential charge down signal, or a differential off signal based on at least one of a phase difference between a reference oscillation and a feedback oscillation and a frequency difference between the reference oscillation and the feedback oscillation;
linearized charge pump operably coupled to produce a positive current signal in response to the differential charge up signal, a negative current signal in response to the differential charge down signal, and zero current signal in response to the differential off signal, wherein the linearized charge pump includes;
first current source module operably coupled to provide a first positive current in response to the differential charge up signal and to provide a first negative current in response to the differential charge down signal;
second current source module operably coupled to provide a second positive current in response to the differential charge up signal and to provide a second negative current in response to the differential charge down signal, wherein the first and second positive currents provide the positive current signal, wherein the first and second negative currents provide the negative current signal, and wherein the first current source module provides the first positive current and the second current source module provides the second negative current or the first current source module provides the first negative current and the second current source module provides the second positive current in response to a modulated differential off signal to produce the zero current signal and high frequency modulated signal components;
modulation module operably coupled to modulate the differential off signal to produce the modulated differential off signal and to pass the differential charge up signal and the differential charge down signal, wherein errors resulting from nonlinearities between the first and second current source modules are substantially contained in the high frequency modulated signal components;
low pass filter operably coupled to attenuate the high frequency modulated signal components and to pass, substantially unattenuated, the positive current signal, the negative current signal, and the zero current signal to produce a filtered signal;
voltage controlled oscillator operably coupled to produce an output oscillation based on the filtered signal; and
divider module operably coupled to divide the output oscillation by divider value to produce the feedback oscillation, wherein the divider value includes at least an integer portion.
4 Assignments
0 Petitions
Accused Products
Abstract
A differential linear fractional N-synthesizer includes a phase and frequency detection module, a linearized charge pump, a low pass filter, a voltage controlled oscillator, and a fractional N divider feedback. The phase and frequency detection module is operably coupled to produce a differential charge-up signal, a differential charge-down signal, or a differential off signal based on phase and/or frequency differences between a reference oscillation and a feedback oscillation. The feedback oscillation is generated by the fractional N divider feedback, which divides an output oscillation by a divider value to produce the feedback oscillation. The linearized charge pump includes a 1st current source, a 2nd current source and a modulation module. In response to the differential off signal, the modulation module produces a modulated differential off signal that causes the 1st and 2nd current sources to produce a zero current signal in an alternating fashion. The low pass filter is operably coupled to attenuate the high frequency signal components produced by the modulation module of the linearized charge pump and to pass the positive, negative or zero current signals to produce a filtered signal. The voltage control oscillator produces the output oscillation based on the filtered signal.
24 Citations
34 Claims
-
1. A differential linear phase locked loop comprises:
-
phase and frequency detection module operably coupled to produce a differential charge up signal, a differential charge down signal, or a differential off signal based on at least one of a phase difference between a reference oscillation and a feedback oscillation and a frequency difference between the reference oscillation and the feedback oscillation;
linearized charge pump operably coupled to produce a positive current signal in response to the differential charge up signal, a negative current signal in response to the differential charge down signal, and zero current signal in response to the differential off signal, wherein the linearized charge pump includes;
first current source module operably coupled to provide a first positive current in response to the differential charge up signal and to provide a first negative current in response to the differential charge down signal;
second current source module operably coupled to provide a second positive current in response to the differential charge up signal and to provide a second negative current in response to the differential charge down signal, wherein the first and second positive currents provide the positive current signal, wherein the first and second negative currents provide the negative current signal, and wherein the first current source module provides the first positive current and the second current source module provides the second negative current or the first current source module provides the first negative current and the second current source module provides the second positive current in response to a modulated differential off signal to produce the zero current signal and high frequency modulated signal components;
modulation module operably coupled to modulate the differential off signal to produce the modulated differential off signal and to pass the differential charge up signal and the differential charge down signal, wherein errors resulting from nonlinearities between the first and second current source modules are substantially contained in the high frequency modulated signal components;
low pass filter operably coupled to attenuate the high frequency modulated signal components and to pass, substantially unattenuated, the positive current signal, the negative current signal, and the zero current signal to produce a filtered signal;
voltage controlled oscillator operably coupled to produce an output oscillation based on the filtered signal; and
divider module operably coupled to divide the output oscillation by divider value to produce the feedback oscillation, wherein the divider value includes at least an integer portion. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A linear charge pump comprises:
-
first current source module operably coupled to provide a first positive current in response to a differential charge up signal and to provide a first negative current in response to a differential charge down signal;
second current source module operably coupled to provide a second positive current in response to the differential charge up signal and a second negative current in response to the differential charge down signal, wherein the first and second positive currents provide a positive current signal, wherein the first and second negative currents provide a negative current signal, and wherein the first current source module provides the first positive current and the second current source module provides the second negative current or the first current source module provides the first negative current and the second current source module provides the second positive current in response to a modulated differential off signal to produce a zero current signal and high frequency modulated signal components; and
modulation module operably coupled to modulate a differential off signal to produce the modulated differential off signal and to pass the differential charge up signal and the differential charge down signal, wherein errors resulting from nonlinearities between the first and second current source modules are substantially contained in the high frequency modulated signal components. - View Dependent Claims (8, 9, 10, 11)
-
-
12. A method for generating an output oscillation, the method comprises:
-
producing a differential charge up signal, a differential charge down signal, or a differential off signal based on at least one of a phase difference between a reference oscillation and a feedback oscillation and a frequency difference between the reference oscillation and the feedback oscillation;
modulating the differential off signal to produce a modulated differential off signal and high frequency modulated signal components;
producing a positive current signal in response to the differential charge up signal;
producing a negative current signal in response to the differential charge down signal;
producing a zero current signal in response to the modulated differential off signal;
filtering the positive current signal, the negative current signal, the zero current signal, and the high frequency modulated signal components such that the high frequency modulated signal components are attenuated and the positive current signal, the negative current signal, and the zero current signal are filtered to produce a filtered signal;
producing the output oscillation based on the filtered signal; and
dividing the output oscillation by divider value to produce the feedback oscillation, wherein the divider value includes at least an integer portion. - View Dependent Claims (13, 14, 15, 16)
-
-
17. An apparatus for generating an output oscillation, the apparatus comprises:
-
processing module; and
memory operably coupled to the processing module, wherein the memory includes operational instructions that cause the processing module to;
produce a differential charge up signal, a differential charge down signal, or a differential off signal based on at least one of a phase difference between a reference oscillation and a feedback oscillation and a frequency difference between the reference oscillation and the feedback oscillation;
modulate the differential off signal to produce a modulated differential off signal and high frequency modulated signal components;
produce a positive current signal in response to the differential charge up signal;
produce a negative current signal in response to the differential charge down signal;
produce a zero current signal in response to the modulated differential off signal;
filter the positive current signal, the negative current signal, the zero current signal, and the high frequency modulated signal components such that the high frequency modulated signal components are attenuated and the positive current signal, the negative current signal, and the zero current signal are filtered to produce a filtered signal;
produce the output oscillation based on the filtered signal; and
divide the output oscillation by divider value to produce the feedback oscillation, wherein the divider value includes at least an integer portion. - View Dependent Claims (18, 19, 20, 21)
-
-
22. A radio comprises:
-
transmitter section operably coupled to receive outbound data and to produce therefrom, in accordance with at least one transmit local oscillation, outbound radio frequency (RF) signals;
receiver section operably coupled to receive inbound RF signals and to produce therefrom, in accordance with at least one receive local oscillation, inbound data; and
local oscillation module operably coupled to produce the at least one transmit local oscillation and the at least one receive oscillation, wherein the local oscillation module includes;
phase and frequency detection module operably coupled to produce a differential charge up signal, a differential charge down signal, or a differential off signal based on at least one of a phase difference between a reference oscillation and a feedback oscillation and a frequency difference between the reference oscillation and the feedback oscillation;
linearized charge pump operably coupled to produce a positive current signal in response to the differential charge up signal, a negative current signal in response to the differential charge down signal, and zero current signal in response to the differential off signal, wherein the linearized charge pump includes;
first current source module operably coupled to provide a first positive current in response to the differential charge up signal and to provide a first negative current in response to the differential charge down signal;
second current source module operably coupled to provide a second positive current in response to the differential charge up signal and to provide a second negative current in response to the differential charge down signal, wherein the first and second positive currents provide the positive current signal, wherein the first and second negative currents provide the negative current signal, and wherein the first current source module provides the first positive current and the second current source module provides the second negative current or the first current source module provides the first negative current and the second current source module provides the second positive current in response to a modulated differential off signal to produce the zero current signal and high frequency modulated signal components;
modulation module operably coupled to modulate the differential off signal to produce the modulated differential off signal and to pass the differential charge up signal and the differential charge down signal, wherein errors resulting from nonlinearities between the first and second current source modules are substantially contained in the high frequency modulated signal components;
low pass filter operably coupled to attenuate the high frequency modulated signal components and to pass, substantially unattenuated, the positive current signal, the negative current signal, and the zero current signal to produce a filtered signal;
voltage controlled oscillator operably coupled to produce an output oscillation based on the filtered signal, wherein the at least one transmit local oscillation and the at least one receive local oscillation are based on the output oscillation; and
divider module operably coupled to divide the output oscillation by divider value to produce the feedback oscillation, wherein the divider value includes at least an integer portion. - View Dependent Claims (23, 24, 25, 26, 27, 28)
-
-
29. A radio frequency (RF) transmitter comprises:
-
baseband modulator operably coupled to produce an in-phase (I) component and a quadrature (Q) component from a data stream;
intermediate frequency (IF) module operably coupled to generate an IF signal from the I and Q components based on a feedback local oscillation;
phase and frequency detection module operably coupled to produce a differential charge up signal, a differential charge down signal, or a differential off signal based on at least one of a phase difference between a reference oscillation and the IF signal and a frequency difference between the reference oscillation and the IF signal;
linearized charge pump operably coupled to produce a positive current signal in response to the differential charge up signal, a negative current signal in response to the differential charge down signal, and zero current signal in response to the differential off signal, wherein the linearized charge pump includes;
first current source module operably coupled to provide a first positive current in response to the differential charge up signal and to provide a first negative current in response to the differential charge down signal;
second current source module operably coupled to provide a second positive current in response to the differential charge up signal and to provide a second negative current in response to the differential charge down signal, wherein the first and second positive currents provide the positive current signal, wherein the first and second negative currents provide the negative current signal, and wherein the first current source module provides the first positive current and the second current source module provides the second negative current or the first current source module provides the first negative current and the second current source module provides the second positive current in response to a modulated differential off signal to produce the zero current signal and high frequency modulated signal components;
modulation module operably coupled to modulate the differential off signal to produce the modulated differential off signal and to pass the differential charge up signal and the differential charge down signal, wherein errors resulting from nonlinearities between the first and second current source modules are substantially contained in the high frequency modulated signal components;
low pass filter operably coupled to attenuate the high frequency modulated signal components and to pass, substantially unattenuated, the positive current signal, the negative current signal, and the zero current signal to produce a filtered signal;
voltage controlled oscillator operably coupled to produce an output RF signal based on the filtered signal, wherein the feedback oscillation is based on the output RF signal and a local oscillation. - View Dependent Claims (30, 31, 32, 33, 34)
-
Specification