Fast-charge pulse shaping circuit

Abstract

Fast-charge shaping circuits and methods for shaping the output of a fast-charge one-shot circuit so as to more precisely shape a fast-charge pulse to a bypass switch placed in parallel with an LNA bias resistor in order to decrease the response time of the LNA to circuit mode changes while minimizing perturbations. Accordingly, the settling time of the LNA during mode changes is less dependent on bias resistance, thereby enabling a Noise Figure improvement. A first approach staggers the release of a fast-charge pulse or pulses over multiple resistor segments to gradually increase the effective resistance of bias resistors. A second approach applies a diode and RC filter to a fast-charge pulse to shape the pulse to gradually increase the effective resistance of bias resistors. A third approach uses an op-amp and timing circuit to control the fast-charge pulse shape to gradually increase the effective resistance of bias resistors.

Dependencies are inferred from the claim text.