High-Efficiency Envelope Tracking Systems and Methods for Radio Frequency Power Amplifiers

A method of dynamically controlling power supplied to a load, comprising:

• receiving an input envelope signal;
• supplying a switch-mode current to a load so that a voltage supplied to the load generally tracks amplitude variations of said input envelope signal;
• in a current sense path, sensing when an instantaneous current required of the load is less than or greater than the switch-mode current being supplied to the load;
• and
• in a main current path separate from said current sense path, supplementing the switch-mode current with a linear regulator current when the instantaneous current required of the load is greater than the switch-mode current being supplied to the load and sinking excess switch-mode current when the instantaneous current required of the load is less than the switch-mode current being supplied to the load, so that the voltage supplied to the load accurately tracks the amplitude variations of said input envelope signal.

A circuit for dynamically controlling the power supplied to a load, comprising:

• means for generating a supply voltage that generally tracks an envelope of an input envelope signal;
• means for detecting when said supply voltage does not accurately track said envelope;
• and
• means for compensating for inaccuracies in tracking the envelope of the input envelope signal,
• wherein said means for detecting is configured to sense a current that is a scaled version of a current being sourced or sunk to the load as said means for compensating is compensating for inaccuracies in tracking the envelope of the input envelope signal.

An error tracking (ET) transmitter, comprising:

• an amplitude modulation path including an envelope modulator having a split-path linear regulator and a switch-mode converter, said envelope modulator having an envelope input configured to receive an amplitude modulation signal, a power supply input configured to receive a direct current (DC) power supply signal, and an output configured to provide an amplitude modulated power supply signal having an envelope that tracks an envelope of said amplitude modulation signal;
• a phase modulation path configured to receive a phase modulation signal and including a phase modulator operable to modulate a carrier signal with the phase modulation signal to generate a phase-modulated carrier signal;
• and
• a power amplifier (PA) having an input port configured to receive said phase-modulated carrier signal and a power supply port configured to receive the amplitude modulated power supply signal from the output of said envelope modulator.