Abstract: A device (400), method (1200), phone (400) and base station (400) provide predistortion for linearization in a radio frequency RF power amplifier. The method includes the steps of: A) predistorting (1201) a baseband signal to provide a predistorted baseband signal in accordance with real-time polynomial coefficients; B) modulating (1202) the predistorted baseband signal to provide an RF signal; C) amplifying (1203) the RF signal to provide an amplified RF signal; D) demodulating (1204) the amplified RF signal to provide a demodulated baseband signal; and E) estimating (1205) the real-time polynomial coefficients to provide a linear amplified RF signal.

Abstract: A method (200) and device (100) provide an efficient linear power amplifier that generates a variable-envelope radio frequency RF signal. The method includes the steps of: A) using an efficient envelope-following unit to output a supply voltage in accordance with a variable envelope of an input baseband signal, wherein using the efficient envelope-following unit includes: 1) using a bandwidth-limiting mapping unit to determine a reference signal based on the baseband signal; and 2) using an envelope-tracking power converter to output a supply voltage, responsive to the reference signal, to the linear RF power amplifier; B) providing an RF input signal with amplitude and phase information to a linear RF power amplifier; and C) using the linear RF power amplifier to output a power-efficient amplified variable-envelope RF signal with substantially a same amplitude and phase information as the RF input signal.

Abstract: A method (300, 400), device (100, 200), phone (200) and base station (200) provide an efficient tracking power converter for variable signals. The tracking power converter includes a feedforward feedback control unit that is coupled to receive a reference signal and to receive at least one feedback signal and is used for determining an optimal control signal in accordance with a predetermined scheme, a pulse width modulation unit that is coupled to the feedforward feedback control unit and is used for modifying a duty ratio to provide a switching signal, and a power converter that is coupled to the pulse width modulation unit and to a power source and is used for providing the dynamic variable output signal.

Abstract: A radio frequency EER-type power amplifier is described in which pulse width modulation is utilized. Input rf signals are split into phase and amplitude paths by a delay line (210). The phase path is coupled to a power amplifier (260). The amplitude path includes an envelope detector (220) coupled to a class S amplifier (270). The class S amplifier is coupled to the power amplifier (260) via a transmission line implemented low pass filter (290). The low pass filter uses strip line transmission lines (410, 510) which may utilize magnetic material (520, 720) to enhance the operation of the low pass filter. The class S amplifier and a transmission line filter provide an amplified, high fidelity replica of the input rf 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 interleaved class S modulator (270), and a power amplifier (260). The interleaved class S modulator (270) amplifies includes multiple channels (272) which each include a portion of a class S modulator. Each class S modulator has a duty cycle and time offset associated therewith. The duty cycles of the channels (272) can be the same with the time offsets different, or the duty cycles can also be different. For an interleaved class S modulator with N channels (272), the slew rate increases by as much as N, and the output ripple decreases by as much as N.sup.2.

Abstract: An amplifier (100) includes an output node (114) having an output voltage (V.sub.out), and a switching amplifier (104) having a first output (132) coupled to the output node for delivering a switching amplifier output current (I.sub.SW) to the output node. The amplifier further includes a modulator (136) coupled to the switching amplifier for controlling the switching amplifier, and a linear amplifier (102) producing a linear amplifier output current (I.sub.lin) through a second output (118) coupled to the output node. The amplifier also includes a feedback network (106) coupled to the modulator for controlling the modulator, the feedback network also coupled to a reference signal (V.sub.ref) which the amplifier apparatus tracks, the feedback network further coupled to a current sense signal (I.sub.sen) proportional to the linear amplifier output current, and coupled to a switching amplifier signal (V.sub.

Abstract: A method and apparatus for generating a modulated signal include a pulse modulation source (215), a pulse modulator (20) for modulating a pulsed signal, a high efficiency power amplifier (230) for amplifying the modulated pulsed signal, and a harmonic reduction filter (240) for passing the switching frequency of the pulsed signal as the RF carrier. The pulse modulation source (215) accepts baseband inphase and quadrature signals and determines phase values and duty ratios for modulating the pulsed signal. The pulse modulator (20) phase modulates and duty cycle modulates the pulsed signal before it is amplified and filtered. A quadrature demodulator (260) produces baseband inphase and quadrature feedback signals for increased linearity.

Abstract: In any steady-state optimization problem, the output being optimized could be a nonmonotonic function of the controlled variable. Often the output is dependent on the temperature, the load impedance, and other unknown and variable quantities. Thus, it is very useful to have an automatic tuning scheme that will take the system to the desired operating point using only input and output information. The present invention is a generalized tuning scheme that uses the correlation between changes in the input and corresponding changes in the output to tune the operating point. In general terms, the present invention utilizes a correlation function between the controlled variable and a perturbed waveform. When the system reaches the desired operating point, the correlation goes to zero and the system converges. This corresponds to the point at which the derivative of the output with respect to the input is zero. This tuning scheme is appropriate for any tuning problem which has a single maximum or minimum.

Abstract: A transformer circuit (10) for a piezoelectric transformer (12) having dual inputs which can piezoelectrically interfere with one another to provide adjustable output gain. The transformer circuit (10) provides two pulse-position-modulated input signals (18, 20) which are substantially identical waveforms, but being phase shifted from one another. When the signals (18, 20) constructively interfere maximum gain is achieved. When the two signals (18, 20) destructively interfere minimum gain is achieved. The waveforms may be of any arbitrary type including square, sine, triangle, sawtooth or irregular. Both input signals (18, 20) are at a resonant frequency of the piezoelectric transformer (12) and have a fifty percent duty cycle so as to always provide highest efficiency within the transformer (12).

Abstract: An active filter provides ripple cancellation in a DC-DC converter. The feedforward filter applies to any converter with an output filter inductor. The filter is inherently stable, performs in both continuous and discontinuous conduction modes, and applies to resonant converters. A suitable linear amplifier, combined with a current transformer, results in a low loss implementation. An adaptive tuning scheme compensates for inductance variation and drift. The filter is usable with buck, push-pull, and boost converter topologies. The result is output ripple below 10 mV.sub.RMS. The filter is effective on converters with outputs as low as 2 V and currents beyond 30 A.