Apparatus and methods for envelope tracking in a mobile device are disclosed herein. In certain configurations, a method includes amplifying a radio frequency (RF) input signal using a power amplifier, providing power to the power amplifier from a power amplifier supply voltage, controlling a voltage level of the power amplifier supply voltage based on a control voltage using a DC-to-DC converter, adjusting the voltage level of the power amplifier supply voltage based on an envelope of the RF input signal using an error amplifier, low pass filtering the power amplifier supply voltage to generate a filtered voltage using a low pass filter, and generating the control voltage based on comparing the filtered voltage to a reference voltage using a comparator.