High Efficiency AC-Coupling Hybrid Envelope Tracking Supply Modulator for LTE Applications

A high efficiency AC-coupling hybrid envelope tracking (ET) supply modulator, based on a hybrid structure consisting of a wideband linear amplifier and a high efficiency buck converter, is presented. Dual-Duty-Control (DDC) scheme based on hysteretic BUCK, which has the real-time voltage adjustment ability, is proposed to realize ac-coupling connection between linear amplifier and the load. The supply modulator is designed in TSMC 65nm process. With the load of 6ohm and 600pF, the supply modulator can reach a peak efficiency of 89.28% @LTE40MHz when the output power is 1.67W.