For the last couple years, “envelope tracking” has caught on as a way to reduce power in phones, cellular base stations, and digital broadcast transmitters. The idea is that RF power amplifiers are most efficient when the signal amplitude runs near the drain voltage, operating in or near saturation or “compression.” When the signal isn’t running that high, then, with a constant power level on the amplifier, the remainder of that power is wasted as heat.
With envelope tracking (ET), the signal envelope is detected and fed to a power modulator that keeps the power amp’s voltage supply in the range of the signal it’s fed.
The OpenET Alliance exists to promote ET and facilitate an ET ecosystem. Towards that end, it just released a set of IP blocks for critical parts of the design. Of course, access to these blocks is touted as a benefit of membership (and, indeed, “… exceed[ing] the value of the first year’s membership fees…”).
More info in their release…