High efficiency wideband linear wireless power amplifier

摘要

An apparatus (150), system (100) and method (400-440) are illustrated for power amplification of an input signal to produce a substantially linear amplified output signal, for broadband wireless applications such as 3G cellular and broadband CDMA systems, without causing significant intermodulation distortion or spectral growth. The preferred system (100) embodiment includes an envelope detector (110) to determine an envelope detector voltage from the input signal; a tracking power supply (120) to determine a supply voltage, preferably as a substantially quantized replica of the envelope detector voltage; an input signal conditioner (150) to determine, in response to the supply voltage, a corresponding phase adjustment and a corresponding gain adjustment, and to modify the input signal using the corresponding phase adjustment and the corresponding gain adjustment to produce a conditioned input signal for power amplification. The preferred system (100) embodiment further includes a power amplifier which operates using the supply voltage, and which amplifies the conditioned input signal to produce the amplified output signal. In the preferred embodiment, the corresponding phase adjustment and a corresponding gain adjustment are separately and independently determined from piecewise linear mappings of a phase response and an amplitude response, respectively, of the power amplifier to a range of variation of the supply voltage.