An ultra-fast tracking power supply (UFTPS) for envelope tracking in a 50kHz 64-QAM Tetra2 base station power amplification system is demonstrated. A simple method for optimizing the step response of the PID+PD sliding-mode control system is presented and demonstrated, along with a PLL-based scheme for locking the switching frequency to an external clock. High UFTPS efficiency (up to 95%), very low ripple (5mVpp) and a fast step response (10μs) are obtained from a single-phase buck converter with a 4th-order output filter. This ripple performance is demonstrated to be critical in the considered application. Also demonstrated is the effect of non-zero UFTPS output impedance on envelope tracking performance. At 13W average (156W peak) RF output, a reduction of DC input power consumption from 93W (14% efficiency) to 54W (24% efficiency) is obtained by moving from a fixed RF power amplifier supply to envelope tracking.
|Title of host publication||Applied Power Electronics Conference and Exposition|
|Publication status||Published - 2008|
|Event||23rd Applied Power Electronics Conference - Austin, TX, United States|
Duration: 24 Feb 2008 → 28 Feb 2008
Conference number: 23
|Conference||23rd Applied Power Electronics Conference|
|Period||24/02/2008 → 28/02/2008|