Abstract: A method and apparatus for efficient power amplification of a wideband signal with a correspondingly wide modulation bandwidth includes splitting means (110), class-G amplifier/modulator (120), and power amplifier (130). Three-level class-G amplifier/modulator (200, FIG. 2) comprises operational amplifier circuits (215, 225), three-state selection circuit (209), switch driver circuit (219), drive signal routing circuit (216), power stage circuit (217), and filter network (218). Multiple power stages are multiplexed based on the amplitude of the envelope signal.

Abstract: A method and apparatus for efficient power amplification of a wideband signal with a correspondingly wide modulation bandwidth includes splitting means (110), class-G amplifier/modulator (120), and power amplifier (130). Three-level class-G amplifier/modulator (200, FIG. 2) comprises operational amplifier circuits (215, 225), three-state selection circuit (209), switch driver circuit (219), drive signal routing circuit (216), power stage circuit (217), and filter network (218). Multiple power stages are multiplexed based on the amplitude of the envelope signal.

Abstract: A method and apparatus for efficient power amplification of a wideband signal with a correspondingly wide modulation bandwidth includes an envelope detector (220), an adaptive split band modulator (270), and a power amplifier (260). The adaptive split band modulator (270) amplifies the low frequency components using a class S modulator (760), and amplifies the high frequency components using a class B amplifier (750). The power supply of the class B amplifier (750) is adaptively modified as a function of the amplitude of the signal that it amplifies. In this manner, the class B amplifier (750) operates at a higher efficiency.

Abstract: A radio frequency signal (FIG. 2, 205) is sampled and the sample is conveyed to a video detector (220). The detected envelope amplitude is sent to an envelope tracking circuit (280), a comparator (230), and an envelope tracking and gate biasing circuit (240). Based on the instantaneous value of the envelope amplitude, the comparator (230) selects one of the available supply voltages (340) via switch drivers (270). The selected one of the available supply voltages (340) is adjusted by the envelope tracking circuit (280) and the resulting voltage output (282) is supplied to the drains of the power amplifiers (390), thus enabling operation near saturation. As the instantaneous value of the envelope amplitude increases, the comparator (230) selects higher supply voltages (340) which increases the voltage conveyed to the power amplifiers (390), thereby increasing their power output.

Abstract: A method and apparatus for efficient power amplification over a wide dynamic range and for a number of modulation formats includes a carrier amplifier (30) and a peaking amplifier (40). The carrier amplifier (30) operates with a bias generated by an envelope amplifier (80) which amplifies the envelope of an input signal as generated by an envelope detector (70). The peaking amplifier (40) operates with a fixed bias. The outputs of the carrier amplifier (30) and the peaking amplifier (40) are combined using an impedance transforming network (50). Envelope amplifier (80) can be turned on for high efficiency low power level operation, or it can be turned off for standard Doherty-type operation.

Abstract: A method and apparatus for efficient power amplification of a wideband signal with a correspondingly wide modulation bandwidth includes an envelope detector (220), an adaptive split band modulator (270), and a power amplifier (260). The adaptive split band modulator (270) amplifies the low frequency components using a class S modulator (760), and amplifies the high frequency components using a class B amplifier (750). The power supply of the class B amplifier (750) is adaptively modified as a function of the amplitude of the signal that it amplifies. In this manner, the class B amplifier (750) operates at a higher efficiency.

Abstract: A class-S modulator (5) receives an input signal (10) having envelope information and pulse-width modulates the input signal (10) using a reference waveform (26) from a waveform generator (25). The envelope becomes a pulse-width modulated signal is level-shifted and amplified through a pre-driver (40). A driver (50) controls switches (60, 70) which drive an output (80) into a low-pass filter (90) wherein the envelope is restored to the amplified signal for driving a power amplifier in a wide-band transceiver.

Abstract: A method and apparatus for efficiently amplifying input signals includes multiple amplifiers (20, 30). Each amplifier receives a signal from a power divider (12) where the input signal is split with substantially equal phase. Each amplifier drives a load (40) through a parallel coupled line pair (26, 36). The parallel coupled line pairs are preferably implemented in micro-strip or strip line technology. Each amplifier includes gate bias inputs (24, 34) and drain bias inputs (22, 32). The gate bias inputs can be biased equally and the drain bias inputs can be biased equally, resulting in a parallel, power combined, amplifier configuration. Alternately, the drain bias inputs can be staggered, or the gate bias inputs can be staggered to increase efficiency.

Abstract: A method and apparatus for efficient power amplification of a wideband signal with a correspondingly wide modulation bandwidth includes an envelope detector (220), an multi-stage class S modulator (270), and a power amplifier (260). The multi-stage class S modulator (270) includes multiple stages (480), where each stage includes a pair of switching transistors (430, 440) and a capacitor (450). The capacitor (450) supplies the inrush current requirements of the stage (480) so that filtering at the switching frequency is substantially provided within the stage (480). Multiple stages (480) are included on a single semiconductor substrate resulting in higher switching frequencies, higher modulation bandwidths, and lower external filtering requirements.

Abstract: A three-way phase shifting power coupler (20) processes a primary signal (26) to provide first, second, and third secondary signals (32, 38, and 44) of substantially equal amplitudes. The first and second secondary signals (32 and 38) are phase shifted to be in-phase relative to the primary signal (26). The third secondary signal (44) is phase shifted to produce a quarter-wavelength difference between third secondary signal (44) and the first and second secondary signals (32 and 38). First, second, and third secondary signals (32, 38, and 44) are provided for distribution into a multi-stage amplifier (22). The power coupler (20) is preferably implemented in microstrip.

Abstract: A method and apparatus for efficient power amplification of a modulated signal includes an envelope detector (220), an multi-output class S modulator (270), a driver amplifier (250), and a power amplifier (260). The multi-output class S modulator (270) amplifies the envelope of the input signal and generates a primary amplified envelope signal and at least one offset amplified envelope signal. The offset amplified envelope signal is used to modulate the driver amplifier (250), and the primary amplified envelope signal is used to modulate the power amplifier (260).

Abstract: A method and apparatus for efficient power amplification with low distortion includes an envelope detector (220), a difference amplifier (130), an envelope amplifier (270), and a power amplifier (260). A feedback path is provided from the output through a second envelope detector (120) to the difference amplifier (130). The feedback circuit operates on the bandwidth of the envelope of the RF signal rather than at the RF bandwidth. An envelope amplifier (270) includes a difference amplifier (272), a pulsewidth modulator (275), a driver (280), switching transistors (285), a low pass filter (290), and a voltage scaler (292). A feedback path within the envelope amplifier reduces the time delay introduced by low pass filter (290). The combined feedback loops work together to reduce distortion and lower intermodulation products.

Abstract: A method and apparatus for efficient power amplification with low phase distortion includes an envelope detector (30), a scaling amplifier (40), a driver amplifier (50), and a power amplifier (60). The scaling amplifier (40), in response to the envelope signal from the envelope detector (30), generates a bias signal which causes predistortion in the driver amplifier (50). The predistortion in the driver amplifier (50) compensates for phase distortion in the driver amplifier (50) and the power amplifier (60), resulting in low phase distortion output. An EER-type amplifier (200) with high efficiency utilizes the predistortion of a driver amplifier (250) to compensate for phase distortion in the driver amplifier (250) and a power amplifier (260).

Abstract: A time-delay compensating class-S modulator (4) receives an input signal (10) having RF envelope information and generates a delay error signal (18) from a comparison to an attenuated output signal. The delay error signal (18) is pulse-width modulated using a reference waveform (26) from a waveform generator (25). The envelope becomes a pulse-width modulated signal and is level-shifted and amplified through a pre-driver (40). A driver (50) controls switches (60, 70) which drive an output (80) into a low-pass filter (90) wherein the envelope is restored to the amplified signal for driving a power amplifier in a wide-band transceiver.

Abstract: A method and apparatus for efficient power amplification with low distortion includes a surface acoustic wave delay line (210), an envelope detector (220), an envelope amplifier (270), and a power amplifier (260). An envelope amplifier (270) includes a pulsewidth modulator (275), a driver (280), switching transistors (285), and a low pass filter (290). The surface acoustic wave delay line (210) functions to balance the delay of the envelope and the carrier of the signal to be amplified. The use of the surface acoustic wave delay line (210) obviates the need for a separate delay line in the phase path of the amplifier.

Abstract: A power amplifier (10) provides linear amplification of noise-like multi-carrier signals over a wide range of power levels. A power divider (40) divides an input signal for distribution in three amplifier networks (70, 72, 74) for selective amplification based upon input signal levels. Each amplifier network (70, 72, 74) is biased to respond when the efficiency of the previous stage diminishes. Successive staging of amplifier networks (70, 72, 74) broadens the efficiency bandwidth of power amplifier (10). A combiner (28) merges output signals from each successive amplifier networks to provide an improved efficiency output to a power amplifier (10) load.

Abstract: A Doherty-type active bias power amplifier (90) suitable for satellite telecommunication systems provides linear amplification of noise-like RF input signals (100) that have multiple carriers spread over a large instantaneous bandwidth. As RF input signal (100) to active bias power amplifier (90) increases, the negative pinch-off voltage that normally causes development of a negative voltage on the gate/base is precluded from occurring in the carrier amplifier (115) and thus an improvement in RF output power is achieved as well as an increase in the dynamic RF input drive range over which high efficiency operation can be achieved. Active biasing provides the proper bias-on point for the peaking amplifier (135) in order to achieve maximum RF efficiency operation.