Envelope power supply calibration of a multi-mode radio frequency power amplifier
View Patent ↗The present disclosure relates to envelope power supply calibration of a multi-mode RF power amplifier (PA) to ensure adequate headroom when operating using one of multiple communications modes. The communications modes may include multiple modulation modes, a half-duplex mode, a full-duplex mode, or any combination thereof. As such, each communications mode may have specific peak-to-average power and linearity requirements for the multi-mode RF PA. As a result, each communications mode may have corresponding envelope power supply headroom requirements. The calibration may include determining a saturation operating constraint based on calibration data obtained during saturated operation of the multi-mode RF PA. During operation of the multi-mode RF PA, the envelope power supply may be restricted to provide a minimum allowable magnitude based on an RF signal level of the multi-mode RF PA, the communications mode, and the saturation operating constraint to provide adequate headroom.
1. Radio frequency (RF) communications circuitry comprising:
RF power amplifier (PA) circuitry associated with a first saturation operating constraint and adapted to:
receive and amplify a first RF input signal to provide a first RF output signal; and
receive an envelope power supply signal, which provides power for amplification;
control circuitry adapted to:
select one of a plurality of communications modes;
determine a maximum allowable magnitude of the first RF input signal based on the first saturation operating constraint, the selected one of the plurality of communications modes, and a magnitude of the envelope power supply signal; and
limit a magnitude of the first RF input signal based on the maximum allowable magnitude; and
RF modulation circuitry adapted to provide the first RF input signal having RF modulation corresponding to the selected one of the plurality of communications modes,
wherein the first saturation operating constraint is based on first calibration data obtained during saturated operation of a calibration RF PA at different envelope power supply levels.
2. The RF communications circuitry of claim 1 wherein the maximum allowable magnitude of the first RF input signal is further based on a maximum allowable magnitude of the first RF output signal, which is based on a maximum RF output power from the RF PA circuitry, such that the maximum RF output power is based on the first saturation operating constraint.