Saturated power amplifier system
A saturated power amplifier system has a saturated power amplifier that receives an input signal. The saturated power amplifier has one or more stages, including one or more output stages. Each output stage produces multiple signals which are combined. Each output stage has one or more levels of cascoding including one or more thick oxide devices and one or more thin oxide devices.
1. A saturated power amplifier system, comprising:
a saturated power amplifier that receives an input signal, the saturated power amplifier having one or more stages including one or more output stages, each of an output stage producing multiple signals which are combined, the output stage having one or more levels of cascoding, the cascoding including one or more thick oxide devices and one or more thin oxide devices, wherein a bias of cascoding devices is increased when a high output voltage is detected;
a power supply coupled to the saturated power amplifier; and
a source of positive feedback that is coupled to the one or more stages of the saturated power amplifier.
2. The system of claim 1 , wherein bias on a thick transistor under non-stress conditions is substantially independent of the output, and bias under high stress conditions moves to provide relief of a stress of the saturated power amplifier system.
3. The system of claim 1 , wherein the system provides a threshold at a certain threshold of stress.
4. The system of claim 3 , wherein the threshold is programmable.
5. The system of claim 1 , wherein bias on a thin cascode is changed.
6. The system of claim 1 , wherein a plurality of thick and thin oxide cascode transistors and are provided to provide for high gain and high output swing which provides power added efficiency (PAE).
7. The system of claim 1 , further comprising:
one or more driver stages.
8. The system of claim 7 , wherein gates of the cascode devices and the supply to the driver stage are modulated to control the shape of and amount distortion (AM-AM and AM-PM).
9. The system of claim 8 , wherein the input signal is pre-distorted.
10. The system of claim 7 , wherein the positive feedback is provided to at least one stage of the power amplifier to square the signals up.
11. The system of claim 7 , wherein a final stage of the driver amplifier is modulated to reduce power leaks from the driver stage.
12. The system of claim 1 , wherein the thin oxide device is a thin oxide driver device.
13. The system of claim 1 , further comprising:
a driver amplifier that drives the output stage of the power amplifier.
14. The system of claim 1 , wherein the saturated power amplifier includes a plurality of output stages.
15. The system of claim 1 , wherein the saturated power amplifier includes a plurality of driver stages.
16. The system of claim 15 , further comprising:
one or more CMOS inverters that drive the output stage.
17. The system of claim 1 , wherein the saturated power amplifier includes a plurality of cascoding devices.
18. The system of claim 1 , wherein the thick oxide device is positioned closer to the output than the thin oxide device.
19. The system of claim 1 , wherein the thick oxide device is configured to provide high voltage capability, and the thin oxide device is configured to provide high gain at high frequency.
20. The system of claim 1 , wherein the multiple signals are combined by through at least one of, the current domain, in a magnetic domain and with a balanced structure.
21. The system of claim 1 , wherein the thick oxide device is a MOS transistor and the thin oxide drive device is a MOS transistor.
22. The system of claim 1 , wherein the saturated power amplifier is a CMOS power amplifier.
23. The system of claim 1 , wherein the saturated power amplifier is a differential power amplifier.
24. The system of claim 1 , wherein the saturated power amplifier is a balanced power amplifier.
25. The system of claim 1 , wherein the thin oxide device provides high gain and the thin oxide driver device provide a large voltage swing from the thick oxide device.
26. The system of claim 1 , the source of the positive feedback is selected from one or more of, cross-coupled transistors and cross-coupling of transistors through capacitors.
27. The system of claim 1 , wherein the positive feedback is provided to the output stage.
28. The system of claim 27 , further comprising:
a chain of CMOS inverters with gradually increasing size that provide a switching function.
29. The system of claim 1 , further comprising:
one or more inductors in one or more of the stages to resonate out a parasitic capacitance.
30. The system of claim 1 , wherein one or more stages of the saturated power amplifier use one or more of the inductors and positive feedback.
31. The system of claim 1 , wherein the supply to the output stage is configured to be modulated to add modulation information to the output signal.
32. The system of claim 1 , wherein the supply to one or more of the drive stages is modulated to provide a wider dynamic range for power control.
33. The system of claim 1 , wherein gates of the cascode devices and the supply to the output stage are modulated to control the shape of and amount distortion (AM-AM and Am-PM).
34. The system of claim 1 , further comprising:
a plurality of thick oxide cascode transistors; and
a plurality of thin oxide driver transistors.
35. The system of claim 34 , where the thick oxide cascode transistors act as switches.
36. The system of claim 35 wherein the thick oxide transistors switch between different load impedances.
37. The system of claim 36 , wherein the power amplifier is a multi-mode part and the load impedances are load impedances for different cellular systems.
38. The system of claim 36 , wherein the power amplifier is a dual band part and the load impedances are load impedances for high band and low band.
39. The system of claim 1 , wherein the input signal to the saturated power amplifier contains phase information.
40. The system of claim 39 , further comprising:
a modulator coupled to the saturated power amplifier, the modulator adding amplitude information to the input signal.
41. The system of claim 40 , wherein the modulator is a polar transmitter.
42. The system of claim 40 , wherein the supply for the saturated power amplifier is modulated to add the amplitude information to the phase information of the input signal.
43. The system of claim 40 , wherein the input signal is pre-distorted.
44. A saturated power amplifier system, comprising:
a saturated power amplifier that receives an input signal, the saturated power amplifier having one or more stages including one or more output stages, each of an output stage producing multiple signals which are combined, the output stage having one or more levels of cascoding, the cascoding including one or more thick oxide devices and one or more thin oxide devices;
a power supply coupled to the saturated power amplifier; and
a source of positive feedback that is coupled to the one or more stages of the saturated power amplifier.