A 40-MHz 85.8%-peak-efficiency switching-converter-only dual-phase envelope modulator for 2-W 10-MHz LTE power amplifier

Abstract

In conventional envelope modulators, a linear regulator is required to attain fast tracking, but it is a significant source of efficiency degradation. To eliminate the linear regulator, a dual-phase switching converter with synchronized adaptive voltage tracking (SAVT) control is employed. The SAVT control enables synchronization and fast hysteretic response for voltage tracking. To overcome the switching converter slew rate limit, a push-pull slew rate enhancer is implemented. The modulator is fabricated with a 0.18μm process and achieves 85.8% peak efficiency tracking a 10MHz LTE envelope.