US Patent 7952431 Linearization circuits and methods for power amplification

Linearization circuits of the invention are used in conjunction with power amplification circuits that comprise a power amplifier core. Exemplary linearization circuits comprise a replica of the power amplifier core. In operation, the linearization produces an envelope signal from an RF signal. The envelope signal is used to control the replica to produce an analog output signal which represents the inverse of the AM to AM distortion of the power amplifier core. The linearization circuit then biases the RF signal with the inverted non-linear signal of the replica to control the power amplifier core. The power amplifier core and the replica thereof can be defined on the same semiconductor die so both respond to process variables similarly.