Apparatus and methods for envelope tracking are disclosed herein. In certain implementations, an envelope tracking system for generating a power amplifier supply voltage for a power amplifier is provided. The envelope tracking system can include a buck converter and an error amplifier configured to operate in parallel to control the voltage level of the power amplifier supply voltage based on an envelope of an RF signal amplified by the power amplifier. The buck converter can convert a battery voltage into a buck voltage that is based on an error current, and the error amplifier can generate the power amplifier supply voltage by adjusting the magnitude of the buck voltage using an output current that is based on the RF input signal's envelope. The error amplifier can control the buck converter by changing a magnitude of the error current in relation to a magnitude of the output current.
