Architecture and method for improving efficiency of a class-A power amplifier by dynamically scaling biasing current thereof as well as synchronously compensating gain thereof in order to maintain overall constant gain of the class-A power amplifier at all biasing configurations thereof

• US 7,535,297 B2
• Filed: 02/27/2007
• Issued: 05/19/2009
• Est. Priority Date: 02/27/2006
• Status: Active Grant

• Current Assignee: Norman Scheinberg, Xinghao Chen, Yanbo Tian
• Original Assignee: Norman Scheinberg, Xinghao Chen, Yanbo Tian
• Inventors: Scheinberg, Norman, Tian, Yanbo, Chen, Xinghao
• Primary Examiner(s): Pascal; Robert
• Assistant Examiner(s): Flanagan; Krista M
• Application Number:
  US11/711,292
• Publication Number:
  US 20070200624A1
• Time in Patent Office: 812 Days
• Field of Search: None
• US Class Current: 330/129
• CPC Class Codes: H03F 1/0261 with control of the polarisation voltage or current, e.g. gliding Class A
• CPC Class Codes: H03F 2200/27 A biasing circuit node being switched in an amplifier circuit
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2200/456 A scaled replica of a transistor being present in an amplifier
• CPC Class Codes: H03G 1/0088 using discontinuously variable devices, e.g. switch-operated

Abstract

An architecture and method for improving efficiency of a Class-A power amplifier by dynamically scaling biasing current thereof as well as synchronously compensating gain thereof in order to maintain overall constant gain of the Class-A power amplifier at all biasing configurations thereof. A biasing-current switching-network is operatively connected to the back-end block of the Class-A power amplifier. A gain-control switching-network is operatively connected to a front-end block of the Class-A power amplifier. A detector-and-control block is operatively connected to an output of the back-end block of the Class-A power amplifier, and samples a signal that is then compared with reference signals to determine switching configurations in the biasing-current switching-network and the gain-control switching network when the signal is processed through the front-end block of the Class-A power amplifier followed by the back-end block of the Class-A power amplifier. The biasing-current switching-network dynamically sets the back-end block biasing current of the Class-A power amplifier for a highest possible operating efficiency. The gain-control network simultaneously adjusts gain of the front-end block of the Class-A power amplifier to synchronize with a dynamic-biasing current-switching configuration to allow overall gain of the Class-A power amplifier to be constant in all biasing conditions.

Claims

1. An architecture for improving efficiency of a Class-A power amplifier, comprising:

a) first means for dynamically scaling biasing current of the Class-A power amplifier by turning ON or OFF biasing current switches to individual transistors of the Class-A power amplifier;

b) second means for synchronously compensating gain of the Class-A power amplifier by dynamically adjusting front-end pre-amplifier'"'"'s gain in order to maintain overall constant gain of the Class-A power amplifier at all biasing configurations of the Class-A power amplifier; and

c) third means for generating synchronized control signals controlling the biasing current switches of the Class-A power amplifier and gain adjusting switches of the front-end pre-amplifier by sampling output of the Class-A power amplifier in real-time with an envelope detector.

2. An architecture for improving efficiency of a Class-A power amplifier by dynamically scaling biasing current thereof as well as synchronously compensating gain thereof in order to maintain overall constant gain of the Class-A power amplifier at all biasing configurations thereof, comprising:

a) a Class-A power amplifier;

b) a biasing-current switching-network;

c) a gain-control switching-network; and

d) a detector-and-control block;

wherein said Class-A power amplifier has an overall constant gain;

wherein said Class-A power amplifier includes a front-end block;

wherein said Class-A power amplifier includes a back-end block;

wherein said back-end block of said Class-A power amplifier follows said front-end block of said Class-A power amplifier;

wherein said front-end block of said Class-A power amplifier has an adjustable gain;

wherein said back-end block of said Class-A power amplifier has an output;

wherein said back-end block of said Class-A power amplifier has an adjustable biasing current;

wherein said biasing-current switching-network is operatively connected to said back-end block of said Class-A power amplifier;

wherein said gain-control switching-network is operatively connected to said front-end block of said Class-A power amplifier;

wherein said detector-and-control block is operatively connected to said output of said back-end block of said Class-A power amplifier;

wherein said detector-and-control block samples a signal that is then compared with reference signals to determine switching configurations in said biasing-current switching-network and said gain-control switching-network when said signal is processed through said front-end block of said Class-A power amplifier followed by said back-end block of said Class-A power amplifier;

wherein said biasing-current switching-network dynamically sets said back-end block of said Class-A power amplifier for a highest possible operating efficiency; and

wherein said gain-control switching network adjusts said gain of said front-end block of said Class-A power amplifier to synchronize with a dynamic-biasing current-switching configuration to allow said overall gain of said Class-A power amplifier to be constant in all biasing conditions.

3. A method for improving efficiency of a Class-A power amplifier, comprising the steps of:

a) dynamically scaling biasing current of the Class-A power amplifier by turning ON or OFF biasing current switches to individual transistors of the Class-A power amplifier;

b) synchronously compensating gain of the Class-A power amplifier by dynamically adjusting front-end pre-amplifier'"'"'s gain in order to maintain overall constant gain of the Class-A power amplifier at all biasing configurations of the Class-A power amplifier; and

c) generating synchronized control signals controlling the biasing current switches of the Class-A power amplifier and gain adjusting switches of the front-end pre-amplifier by sampling output of the Class-A power amplifier in real-time with an envelope detector.

4. A method for improving efficiency of a Class-A power amplifier by dynamically scaling biasing current thereof as well as synchronously compensating gain thereof in order to maintain overall constant gain of the Class-A power amplifier at all biasing configurations thereof, comprising the steps of:

a) operatively connecting a biasing-current switching-network to a back-end block of a Class-A power amplifier;

b) operatively connecting a gain-control switching-network to a front-end block of the Class-A power amplifier;

c) operatively connecting a detector-and-control block to an output of the back-end block of the Class-A power amplifier;

d) processing a signal through the front-end block of the Class-A power amplifier followed by the back-end block of the Class-A power amplifier;

e) sampling, by the detector-and-control block, a signal;

f) comparing the signal with reference signals;

g) determining switching configurations in the biasing-current switching-network and the gain-control switching-network;

h) dynamically setting, by the biasing-current switching-network, a biasing current of the back-end block of the Class-A power amplifier to a highest possible operating efficiency; and

i) simultaneously adjusting, by the gain-control switching-network, a gain of the front-end block of the Class-A power amplifier to synchronize with a dynamic-biasing current-switching configuration to allow an overall gain of the Class-A power amplifier to be constant in all biasing conditions.