Power supply modulator, power supply modulation method and communication device

The invention discloses a power supply modulator, a power supply modulation method and a communication device, relates to the technical field of wireless communication, and aims to solve the problem that a radio frequency power amplifier adopts constant voltage to supply power, so that the working efficiency is sharply deteriorated under the condition of power back-off. The power supply modulator comprises a linear amplification module, a comparison module, a logic control module and a switch conversion module. The linear amplification module amplifies an input envelope signal and then provides a modulation voltage corresponding to the amplitude of the amplified envelope signal to the radio frequency power amplifier. The comparison module provides a first control signal for the logic control module based on the envelope signal and a reference signal; and a second control signal is provided for the logic control module based on the output signal of the linear amplification module and the output signal of the s