FLIR Systems, Inc.
Automatic bias controller for a pulsed power amplifier

Abstract:

Systems and methods for automatically controlling the bias in a pulsed power amplifier include components for measuring the current in an amplifier, comparing the measured value with the desired value, modifying the bias, and controlling the bias applied to the power amplifier. A measurement circuit converts the measured current to a voltage, and a comparator compares a measured voltage with a reference voltage to continuously indicate whether the amplifier current is less than a desired quiescent value. A circuit controls the level of the gate-bias (Vg) during a pulse, such as with a pulse width modulator. The measurement of the amplifier current is registered after the bias is enabled, but before the signal pulse. Drive control logic implements a control algorithm for adjusting the gate value in between pulses and in time to be used for the next pulse.