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  • Print publication year: 2015
  • Online publication date: June 2015

9 - Dynamic power supplies

from Part II - DPST circuit issues

Summary

Power supplies are traditionally designed to provide very stable and well-regulated outputs, primarily a fixed voltage that is maintained irrespective of the current that is drawn by its load. When the supply voltage is fixed in this way, there is no need to be concerned with the reactive characteristics of the load. All that matters is the value of the load resistance, which is often time-varying. Power supply regulation control loop dynamics are designed with this restriction in mind.

Here we require that the value of the output voltage from the power supply be dynamic, meaning not only that it can vary, but that it must be capable of varying at speeds matching the variation of its time-varying load. Combine this with a load having a widely varying resistance value as the voltage across it changes, as seen in Section 5.10, and the design of any dynamic power supply (DPS) becomes a formidable task.

This leads to the important concept that in any DPS transmitter there is a new interface of great importance: the interconnection between the DPS and its associated PA. To date, this interface has not received much attention, probably because of the general complacency afforded traditional design when fixed power supply voltages are used.

This chapter examines the issues involved in DPS design, including some circuit details.

Power objectives

All power into the PA flows through the DPS. The DPS must support the combination of: the PA output RF signal power, the energy in efficiencies of the PA due to its own power dissipation, and any reactive currents required by PA circuitry. Very much like the general electric utility, the DPS must source the total current required by the load, not just the resistive component that leads to output RF power and internal power dissipation. The utility concept of the power factor [9-1] is very important to DPS design.

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[9-1] R. J.Smith, Smith,Circuits, Devices, and Systems, 2nd edn. J. Wiley & Sons, New York, 1971.
[9-2] R.Broderson, Broderson,“The Network Computer and its Future,”Proceedings of the 1997 International Solid State Circuits Conference (ISSCC97), Keynote presentation, pp. 32–36.
[9-3] M.Dunsmore, Dunsmore,E.McCune, McCune, and G.Do, Do, “Polar Modulation Transmitter with Envelope Modulator Path Switching,” US Patent 8301088, issued Oct. 30, 2012.
[9-4] E.McCune, McCune,“pPSK for Bandwidth and Energy Efficiency,”Proceedings of the 43rd European Microwave Conference (EuMC), Nuremberg, October 2013.
[9-5] E.McCune, McCune,“Process- and Technology-Independent Power Switching Transistor Figures of Merit,”Proceedings of the 2008 IEEE Radio and Wireless Symposium (RWS), Jan. 2008, pp. 195–198.
[9-6] B.Silic, Silic, “Switchmode Supply and Driving Method for Efficient RF Amplification,” US Patent 6867574, issued March 15, 2005.
[9-7] W.Sander, Sander, “Boost Doubler Circuit,” US Patent 6522192, issued Feb. 18, 2003.
[9-8] E.McCune, McCune, “Extremely High-speed Switchmode DC-DC Converters,” US Patent 7026797, issued April 11, 2006, Patent 7227342, issued June 5, 2007, and Patent 7906944, issued March 15, 2011.
[9-9] E.McCune, McCune, “High Efficiency Modulation RF Amplifier,” US Patent 6377784, issued April 23, 2002, US Patent 7099635, issued Aug. 29, 2006, US Patent 7395038, issued July 1, 2008.
[9-10] W.Sander, Sander,R.Meck, Meck, and E.McCune, McCune,“High-efficiency Modulating RF Amplifier,” US Patent 6816016, issued Nov. 9, 2004.
[9-11] E., McCune and W.Sander, Sander, “High-efficiency Amplifier Output Level and Burst Control,” US Patent 6864668, issued March 8, 2005.
[9-12] B., Silic and E.McCune, McCune, “Enhanced Hybrid Class S Modulator,” US Patent 7558334, issued July 7, 2009.
[9-13] E.McCune, McCune,, “Signaling Transition Control in a Modulated Signal Communication System,” US Patent 5321799, issued June 14, 1994.
[9-14] W.Sander, Sander, “Saturation Prevention and Amplifier Distortion Reduction,” US Patent 6528975, issued March 4, 2003.
[9-15] K.Cioffi, Cioffi,N.Tolson, Tolson, and E.McCune, McCune, “Power Supply Processing for Power Amplifiers,” US Patent 6781452, issued Aug. 24, 2004, US Patent 6924695, issued Aug. 2, 2005, US Patent 7038536, issued May 2, 2006, US Patent 7642847, issued Jan. 5, 2010.
[9-16] C.Pennec, Pennec, “Automatic Low Battery Compensation Scaling Across Multiple Amplifier Stages,” US Patent 7554395, issued June 30, 2009.
[9-17] E.McCune, McCune, “Envelope Modulator Saturation Detection Using a DC-DC Converter,” US Patent 7702300, issued April 20, 2010.
[9-18] R., Booth and E.McCune, McCune, “VSWR Normalizing Envelope Modulator,” US Patent 8331882, issued Dec. 11, 2012.