Programmable radio transceiver
View Patent ↗A fully integrated, programmable mixed-signal transceiver comprising a radio frequency integrated circuit (RFIC) which is frequency and protocol agnostic with digital inputs and outputs, the transceiver being programmable and configurable for multiple radio frequency bands and standards and being capable of connecting to many networks and service providers. The RFIC does not use spiral inductors and instead includes transmission line inductors allowing for improved scalability. Components of the transceiver are programmable to allow the transceiver to switch between different frequency bands of operating. Frequency switching can be accomplished though the content of digital registers coupled to the components.
1. A frequency synthesizer implemented as a phase-locked loop without mixers, the phase-locked loop comprising:
a first voltage-controlled oscillator;
a second voltage-controlled oscillator;
a first resonance circuit coupled to the first voltage-controlled oscillator and adapted to produce a first tuning signal to tune a frequency range of a first frequency signal produced by the first voltage controlled oscillator;
a second resonance circuit coupled to the second voltage-controlled oscillator and adapted to produce a second tuning signal to tune a frequency range of a second frequency signal produced by the second voltage controlled oscillator;
a switch;
two cascaded divide-by-N circuits coupled to the first and second voltage-controlled oscillators via the switch, wherein the switch is operable to couple at least one of the first frequency signal and the second frequency signal to the cascaded divide-by-N circuits; and
a divide-by-M circuit coupled to the cascaded divide-by-N circuits in a feedback loop with the first and second voltage-controlled oscillators.
2. The frequency synthesizer of claim 1 , further comprising:
a phase detector coupled to the divide-by-M circuit in the feedback loop between the divide-by-M circuit and the first and second voltage-controlled oscillators; and
a loop filter coupled between the phase detector and the first and second voltage-controlled oscillators.
3. The frequency synthesizer of claim 1 , wherein at least one of the first and second resonance circuits comprises:
a first tunable capacitance;
a second tunable capacitance coupled in series with the first tunable capacitance; and
an inductor coupled in parallel with the first and second tunable capacitances.
4. The frequency synthesizer of claim 3 , wherein the first tunable capacitance comprises a switchable bank of fixed value capacitors.
5. The frequency synthesizer of claim 4 , wherein the switchable bank of fixed value capacitors comprises a plurality of MOS capacitor banks which are electronically switchable responsive to a control signal.
6. The frequency synthesizer of claim 4 , wherein the switchable bank of fixed value capacitors comprises a plurality of MIM capacitor banks which are electronically switchable responsive to a control signal.
7. The frequency synthesizer of claim 3 , wherein the second tunable capacitance comprises at least one variable capacitor.
8. The frequency synthesizer of claim 7 , wherein the at least one variable capacitor comprises at least one varactor diode.
9. The frequency synthesizer of claim 3 , wherein the frequency synthesizer is implemented as an integrated circuit coupled to a lead frame; and wherein the inductor comprises at least one bondwire interconnecting, the lead frame and a bond pad on the integrated circuit.
10. The frequency synthesizer of claim 9 , wherein the at least one bondwire comprises at least two mutually coupled bondwires.
11. The frequency synthesizer of claim 9 , wherein the at least one bondwire comprises a plurality of bondwires coupled end-to-end in a meandering configuration between the bond pad and the lead frame.
12. The frequency synthesizer of claim 9 , wherein the at least one bondwire comprises a plurality of bondwires coupled end-to-end in a spiral configuration between the bond pad and the lead frame.
13. The frequency synthesizer of claim 1 , wherein the divide-by-M circuit comprises a digitally programmable divide-by-M circuit.
14. The frequency synthesizer of claim 13 , wherein the digitally programmable divide-by-M circuit comprises a digitally programmable multistage noise shaping Delta-Sigma modulator.
15. The frequency synthesizer of claim 1 , wherein the divide-by-M circuit has a settling time of approximately 10 microseconds.
16. The frequency synthesizer of claim 1 , wherein each of the first and second voltage controlled oscillators has a tuning range of approximately 18%.
17. The frequency synthesizer of claim 1 , wherein a frequency range of each of the first and second voltage controlled oscillators and a divide ratio of each of the first and second divide-by-N circuits are selected such that the frequency synthesizer has a frequency range of approximately 488 MHz to approximately 3900 MHz.
18. The frequency synthesizer of claim 1 , wherein each of the first and second divide-by-N circuits has a digitally programmable divide ratio.