Inverter/Power Amplifier With Capacitive Energy Transfer and Related Techniques

• US 20150171768A1
• Filed: 03/13/2013
• Published: 06/18/2015
• Est. Priority Date: 11/11/2008
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Perreault, David J.
• Granted Patent: US 9,634,577 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps
• CPC Class Codes: H02M 7/537 using semiconductor devices only, e.g. single switched pulse inverters
• CPC Class Codes: H03F 1/0227 using supply converters
• CPC Class Codes: H03F 1/025 by using a signal derived from the input signal
• CPC Class Codes: H03F 1/3282 Acting on the phase and the amplitude of the input signal
• CPC Class Codes: H03F 2200/204 A hybrid coupler being used at the output of an amplifier circuit
• CPC Class Codes: H03F 2200/345 Pulse density modulation being used in an amplifying circuit
• CPC Class Codes: H03F 2200/348 Pulse frequency modulation being used in an amplifying circuit
• CPC Class Codes: H03F 2200/351 Pulse width modulation being used in an amplifying circuit
• CPC Class Codes: H03F 2200/511 Many discrete supply voltages or currents or voltage levels can be chosen by a control signal in an IC-block amplifier circuit
• CPC Class Codes: H03F 2201/3209 the amplifier comprising means for compensating memory effects
• CPC Class Codes: H03F 3/211 using a combination of several amplifiers H03F3/60 takes precedence
• CPC Class Codes: H03F 3/2171 with field-effect devices H03F3/2173 - H03F3/2178 take precedence
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• CPC Class Codes: H03F 3/602 Combinations of several amplifiers
• CPC Class Codes: H03F 3/68 Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics power amplifiers using a combination of several semiconductor amplifiers H03F3/211; combinations of amplifiers using coupling networks with distributed constants H03F3/602

Abstract

Circuit topologies and control methods for a dc-to-rf converter circuit are described.

Claims

1. A circuit for providing dc-to-rf conversion comprising:

a first power conversion stage adapted to receive an input voltage and in response thereto to provide an output voltage at an output thereof; and

a second power conversion stage adapted to receive a signal from said first stage and deliver power to an output, wherein;

said first power conversion stage comprises a reconfigurable switched capacitor (SC) voltage modulator configured to provide a plurality of voltage conversion ratios from its input to its output and said reconfigurable switched capacitor (SC) voltage modulator having a pair of input terminals adapted to be coupled to an input voltage source and a pair of output terminals adapted to be coupled to input terminals of said second power conversion stage; and

said second power conversion stage comprises at least one of;

an RF amplifier;

or a power supply input of an RF amplifier.

4. The circuit of claim 1 wherein said first power conversion stage comprises a multilevel switched-capacitor circuit core coupled to said second stage through an output configuration switch bank.

7. The circuit of claim 1 wherein said first power conversion stage comprises a multilevel switched-capacitor circuit core configured to be coupled to at least one input source through an input configuration switch bank.

13. The circuit of claim 1 further comprising means for dynamically controlling a conversion ratio of the first power conversion stage such that an intermediate voltage can be modulated as a function of any of:

(a) an input voltage;

(b) a reference voltage;

or (c) an rf output amplitude.

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16. A switched-mode capacitor voltage modulator circuit comprising:

a first stage comprising an energy transfer capacitor and a switch network having at least five switches, said switch network coupled about said single energy transfer capacitor such that said first stage effectively provides one of at least four voltage levels at an output thereof and permits rapid dynamic switching among levels; and

a second stage having an input coupled to the output of said first stage such that said second stage is adapted to receive each of the four voltage levels.

23. The circuit of claim 16 further comprising a feedforward signal path coupled between the voltage modulator and controls for the power amplifier stage to feedforward a voltage modulator output voltage to the controls for the power amplifier stage to thereby reduce memory effects in the power amplifier system.

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24. A system for coupling at least one input source to at least one load, the system comprising:

an input configuration switch bank having one or more input ports and one or more output ports;

a multilevel switched-capacitor voltage circuit core providing a plurality of voltage levels having steady-state ratiometric relationships, at least one of said levels coupled to at least some of the one or more output ports of said input configuration switch bank; and

an output configuration switch bank having two or more input ports and one or more output ports, with each of the two or more input ports coupled to said voltage levels of said multilevel switched-capacitor voltage circuit and each of the one or more output ports configured to be selectively coupled to at least one of the at least one loads.

28. The system of claim 24 wherein said input configuration switch bank comprises a first set of input configuration switches to provide the input and/or output ports.

31. The system of claim 24 wherein said input configuration switch bank comprises a plurality of input configuration switches, each of the switches having an input configured to selectively couple to at least one of the at least one input sources.

32. The system of claim 24 wherein said output configuration switch bank comprises a plurality of output configuration switches.

33. The system of claim 24 wherein said output configuration switch bank comprises a first plurality of switches configured to be selectively coupled to a first one of the one or more loads and a second plurality of switches configured to be selectively coupled to a second, different one of the one or more loads.

38. The system of claim 24 wherein said system is provided as an Asymmetric Multilevel Backoff (AMBO) system.

39. The system of claim 24 wherein:

said reconfigurable switched-capacitor voltage circuit comprises a plurality of switches operable to provide switched-capacitor voltage conversion yielding four or more steady-state ratiometric relationships among a plurality of voltages V₁-V₄; and

said input configuration switch bank comprises a first set of input selector switches and said output configuration switch bank comprises a first set of output selector switches wherein said input selector switches and said output selector switches are operable to enable a steady-state conversion ratio from input voltage V_in to a voltage v_x supplied to an amplifier to be dynamically reconfigured.

40. The system of claim 39 wherein said system comprises M input selector switches S_im and N output selector switches S_onx and wherein steady-state voltages at the switched-capacitor voltage circuit output v_x are selected as a function of the selector switch configurations and wherein placing certain ones of input and output selector switches S_im and S_onx in their ON state results a steady state voltage v_x=(n/m) V_in.

41. The system of claim 39 wherein a state of output selector switches S_o1x-S_o4x may be changed to rapidly modulate a voltage provided at the power amplifier without the inducing significant variations in voltages V₁-V₄ such that rapid discrete drain modulation of the power amplifier is provided in response to rapid changes in a desired output amplitude.

42. The system of claim 39 wherein said input selector switches S_i1-S_i4 are configured such that changing a state of input selector switches S_i1-S_i4 rescales capacitor voltages to thereby reconfigure a set of voltages provided at the power amplifier with respect to the input voltage V_in.

43. The system of claim 39 wherein said output selector switches provide rapid modulation of an output voltage v_x of said reconfigurable switched-capacitor voltage circuit among a set of available voltages V₁-V₄, while said input selector switches provide discrete slow-time-scale adjustment of the set of voltages V₁-V₄.

44. The system of claim 39 wherein said switched-capacitor energy transfer among different levels is accomplished by modulating switches in said reconfigurable switched-capacitor voltage circuit on and off and wherein a first set of switches in said reconfigurable switched-capacitor voltage circuit are alternately turned on and off in complementary states with a second set of switches in said reconfigurable switched-capacitor voltage circuit such that an interleaved system with continuous input and output currents is provided thereby reducing a need for added filtering and decoupling.

45. The system of claim 39 wherein said reconfigurable switched-capacitor voltage circuit comprises a first set of capacitors and a second set of capacitors corresponding to energy transfer capacitors and where said first set of capacitors are provided having a capacitance which is relatively small compared with the capacitance of the second set of capacitors such that a load [provided by an amplifier] may be used to soft charge and discharge said energy transfer capacitors in whole or in part.

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