LOAD CURRENT SENSOR FOR ENVELOPE TRACKING MODULATOR

摘要

An apparatus and method for sensing load current of an envelope tracking (ET) modulator enables load impedance of a power amplifier to be measured. Impairments associated with the load impedance characteristic can be suppressed by calibration and predistortion instead of by feedback (as done in the prior art). The ET modulator provides a switching regulator that can be reconfigured as a linear regulator for the purpose of sensing the load current. This allows the ET modulator to be operated open-loop, thereby eliminating the power consumption overhead resulting from utilization of a loop filter and error amplifier (used in the prior art) and achieving a higher overall efficiency.