Claims
- 1. A transconductance amplifier comprising:
a transconductance cell for receiving one or more input voltage signals and for generating one or more first currents using the input voltage signals, the transconductance cell being used to supply a current output including at least a portion of the first currents; and high-swing circuitry for receiving the input voltage signals, for generating one or more second current signals using the input voltage signals and for providing at least a portion of the second current signals to the transconductance cell to be included in the current output, wherein the first currents provide more than half of the current output while the input voltage signals are within first range of voltages, and wherein the second currents provide more than half of the current output while the input voltage signals are not within the first range of voltages.
- 2. The transconductance amplifier of claim 1, wherein the transconductance cell comprises a current source transistor that supplies substantially less current to be used as the first currents when the input voltages signals are not within the first range of voltages as compared to when the input voltages signals are within the first range of voltages.
- 3. The transconductance amplifier of claim 2, wherein the transconductance cell further comprises one or more input transistors coupled to the current source transistor, and the input transistors are used to receive the input voltage signals, and wherein the input transistors provide sufficiently high voltage to the current source transistor so as to push the current source transistor into triode region of operation when the input voltage signals are not within the first range of voltages.
- 4. The transconductance amplifier of claim 2, wherein the high-swing circuitry comprises one or more input transistors for receiving the input voltage signals and for generating the second current signals using the input voltage signals, wherein the input transistors conduct substantially more currents when the input voltage signals are not within the first range of voltages as compared to when the input voltage signals are within the first range of voltages.
- 5. The transconductance amplifier of claim 4, wherein the input transistors are coupled to one or more current supply transistors, the current supply transistors being coupled to one or more current mirror transistors, wherein currents flowing through the current supply transistors increase as the input voltage signals increase, currents flowing through the current mirror transistors increase as the currents flowing through the current supply transistors increase, and wherein at least a portion of the currents flowing through the current mirror transistors are provided as the second currents to the transconductance cell to be included in the current output.
- 6. A method of generating a current output using a transconductance amplifier comprising a transconductance cell and high-swing circuitry, the method comprising the steps of:
receiving one or more input voltage signals; generating one or more first currents in the transconductance cell for inclusion in the current output; and generating one or more second currents in the high-swing circuitry for inclusion in the current output, at least a portion of the second currents being provided to the transconductance cell for inclusion on the current output, wherein the first currents provide more than half of the current output while the input voltage signals are within first range of voltages, and wherein the second currents provide more than half of the current output while the input voltage signals are not within the first range of voltages.
- 7. The method of claim 6, wherein the transconductance cell comprises a current source transistor that supplies substantially less current to be used as the first currents when the input voltages signals are not within the first range of voltages as compared to when the input voltages signals are within the first range of voltages.
- 8. The method of claim 7, wherein the transconductance cell further comprises one or more input transistors coupled to the current source transistor, and the input transistors are used to receive the input voltage signals, and wherein the input transistors provide sufficiently high voltage to the current source transistor so as to push the current source transistor into triode region of operation when the input voltage signals are not within the first range of voltages.
- 9. The method of claim 7, wherein the high-swing circuitry comprises one or more input transistors for receiving the input voltage signals and for generating the second current signals using the input voltage signals, wherein the input transistors conduct substantially more currents when the input voltage signals are not within the first range of voltages as compared to when the input voltage signals are within the first range of voltages.
- 10. The method of claim 9, wherein the input transistors are coupled to one or more current supply transistors, the current supply transistors being coupled to one or more current mirror transistors, wherein currents flowing through the current supply transistors increase as the input voltage signals increase, currents flowing through the current mirror transistors increase as the currents flowing through the current supply transistors increase, and wherein at least a portion of the currents flowing through the current mirror transistors is provided as the second currents to the transconductance cell to be included in the current output.
- 11. A charge pump comprising:
an i/o circuit for receiving one or more voltage difference signals and for generating a voltage control signal and one or more input voltage signals; and a transconductance amplifier having a transconductance cell and high-swing circuitry, the transconductance amplifier being used to provide a current output to the i/o circuit, the current output being used to provide charge for the voltage control signal, wherein the voltage control signal and the input voltage signals are generated based on the voltage difference signals, and wherein the transconductance cell generates more than half of the current output when the input voltage signals are within a first range of voltages and the high-swing circuitry generates more than half of the current output when the input voltage signals are not within the first range of voltages.
- 12. The charge pump of claim 11, wherein the high-swing circuitry generates more than half of the current output when the input voltage signals are at a voltage level above the highest level of the first range of voltages.
- 13. A method of providing a voltage control signal using a charge pump comprising an i/o circuit and a transconductance amplifier having a transconductance cell and high-swing circuitry, the method comprising the steps of:
receiving one or more voltage difference signals; generating a voltage control signal and one or more input voltage signals using the voltage difference signals; and generating a current output signal in the transconductance amplifier using the input voltage signals, the current output signal being used to provide charge for the voltage control signal, wherein the transconductance cell generates more than half of the current output when the input voltage signals are within a first range of voltages and the high-swing circuitry generates more than half of the current output when the input voltages are not within the first range of voltages.
- 14. The method of claim 13, wherein the high-swing circuitry generates more than half of the current output when the input voltages are at a voltage level above the highest level of the first range of voltages.
- 15. A phase-locked loop (PLL) comprising:
a phase detector for receiving a reference clock signals and a voltage controlled oscillator (VCO) output signal, and for generating one or more voltage difference signals; a charge pump for receiving the voltage difference signals and for generating a voltage control signal with sufficient charge for VCO operation; and a VCO for receiving the voltage control signal and for generating the VCO output signal based on the voltage control signal, wherein the charge pump comprises a transconductance cell and a high-swing circuitry, wherein the transconductance cell generates more than half of the charge when the VCO output signal is within a first range of voltages and the high-swing circuitry generates more than half of the charge when the VCO output signal is not within the first range of voltages.
- 16. The PLL of claim 15, wherein the voltage difference signals include one or more up signals and one or more down signals, wherein the up signals are asserted when the VCO output signal lags in phase of or has higher frequency than the reference clock signal, and wherein the down signals are asserted when the VCO output signal leads in phase or has lower frequency than the reference clock signal.
- 17. The PLL of claim 16, wherein at least one of the up signals and the down signals include a differential pair of signals.
- 18. A method of phase locking a voltage controlled oscillator (VCO) output signal to a reference clock signal using a phase-locked loop (PLL) comprising a phase detector, a charge pump having a transconductance cell and high-swing circuitry, and a VCO, the method comprising the steps of:
receiving the reference clock signal and a VCO output signal in the phase detector; generating one or more voltage difference signals using the reference clock signal and the VCO output signal; using the voltage difference signals to generate a voltage control signal in the charge pump, the voltage control signal having sufficient charge for VCO operation; and generating the VCO output signal in the VCO using the voltage control signal, wherein the transconductance cell generates more than half of the charge when the VCO output signal is within the first range of voltages and the high-swing circuitry generates more than half of the charge when the VCO output signal is not within the first range of voltages.
- 19. The method of claim 18, wherein the voltage difference signals include one or more up signals and one or more down signals, wherein the up signals are asserted when the VCO output signal lags in phase of or has higher frequency than the reference clock signal, and wherein the down signals are asserted when the VCO output signal leads in phase or has lower frequency than the reference clock signal.
- 20. The method of claim 19, wherein at least one of the up signals and the down signals include a differential pair of signals.
- 21. A transconductance amplifier comprising:
first means for receiving one or more input voltage signals and for generating one or more first currents using the input voltage signals, the first means being used to supply a current output including at least a portion of the first currents; and second means for receiving the input voltage signals, for generating one or more second current signals using the input voltage signals and for providing at least a portion of the second current signals to the transconductance cell to be included in the current output, wherein the first currents provide more than half of the current output while the input voltage signals are within first range of voltages, and wherein the second currents provide more than half of the current output while the input voltage signals are not within the first range of voltages.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority of provisional U.S. patent application Ser. No. 60/235,725 entitled “High-Swing Transconductance Amplifier for Charge Pump Circuit,” filed Sep. 27, 2000, the contents of which are hereby incorporated by reference in full. The present applications contains subject matter related to the subject matter disclosed in a commonly owned U.S. Patent Application (Attorney Docket Number 41586/PBH/B600) entitled “Variable Transconductance Variable Gain Amplifier Utilizing a Degenerated Differential Pair,” filed Feb. 8, 2001, the contents of which are incorporated by reference in full.
Provisional Applications (1)
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Number |
Date |
Country |
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60235725 |
Sep 2000 |
US |