The present invention is a high efficiency AM switching voltage regulator used to provide an AM output signal to an AM RF power amplifier, wherein the AM output signal is proportional to an AM input signal. The AM output signal includes an AM output voltage and an AM supply current, which represents a sum of an AM output current and a shunt current The AM output voltage provides an envelope supply voltage to the AM RF power amplifier. The switching voltage regulator includes a switching current regulator coupled to a linear shunt voltage regulator. The switching current regulator provides AM output current for the AM RF power amplifier and a small amount of shunt current for the linear shunt voltage regulator, which regulates the AM output voltage by controlling the shunt current. The switching current regulator regulates the AM supply current in proportion to a time-averaged value of shunt current.