CPC H03F 1/0216 (2013.01) [H03F 3/245 (2013.01); H04B 1/3827 (2013.01); H04B 1/40 (2013.01); H03F 2200/105 (2013.01); H03F 2200/451 (2013.01)] | 20 Claims |
1. A mobile device comprising:
a front end circuit including a power amplifier configured to amplify a radio frequency signal and to receive power from a power amplifier supply voltage; and
a power management circuit including an envelope tracker configured to control the power amplifier supply voltage based on an envelope signal indicating an envelope of the radio frequency signal, the envelope tracker including a first controllable resistance between a first regulated voltage and the power amplifier supply voltage and a second controllable resistance between a second regulated voltage and the power amplifier supply voltage, the first regulated voltage and the second regulated voltage of different voltage levels, the first controllable resistance including a first plurality of selectable paths each having a different resistance, the first plurality of selectable paths each including a resistor and a switch.
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