Patent ID: 6525611
Filing Date: 2003-02-25
Classification: H03F

Abstract:
An amplifier with protection for over-voltage conditions comprising:a) amplifier circuitry adapted to amplify a radio frequency (RF) inpuit signal to provide an RF output signal wherein the amplifier circuitry has a gain controlled by a bias signal; b) a voltage divider adapted to divide the RF output signal and provide a divided output signal for comparison with a voltage reference corresponding to a voltage threshold; c) a current mirror generating an over-voltage current corresponding to the amount the divided output signal exceeds the voltage reference; d) operational amplifier circuitry adapted to process the over-voltage current to generate a bias control signal when the RF output signal exceeds the voltage threshold; and e) a bias network adapted to generate the bias signal to control the gain of the amplifier circuitry and reduce the bias signal as a function of the bias control signal wherein the bias signal is reduced to reduce the gain of the amplifier circuitry when the RF output signal exceeds the voltage threshold.