Patent ID: 9136803
Filing Date: 2015-09-15
Classification: H03F,H03G,H04B

Abstract:
1. A mobile device comprising: a transmitter configured to generate a radio frequency (RF) signal and an enable signal; a power amplifier configured to receive the RF signal and a bias current, the power amplifier having an enabled state and a disabled state, the power amplifier configured to amplify the RF signal in the enabled state; and a bias circuit configured to receive the enable signal and to generate the bias current of the power amplifier based on the enable signal, the bias circuit including a time-dependent signal generator configured to shape the enable signal to generate a control current, a current amplifier configured to amplify the control current to generate a correction current, and a primary biasing circuit configured to generate the bias current based on the correction current, the bias circuit configured to adjust a magnitude of the bias current over time to compensate for a variation in gain of the power amplifier associated with transitioning the power amplifier from the disabled state to the enabled state, the time-dependent signal generator including a resistor-capacitor (RC) network including an input configured to receive the enable signal and an output configured to generate the control current, the RC network including a first resistor and a first capacitor electrically connected in series between the input of the time-dependent signal generator and the output of the time-dependent signal generator, the RC network further including a second resistor having a first end electrically connected to the input of the time-dependent signal generator and a second end electrically connected to the output of the time-dependent signal generator.