Apparatus and method for low power operation with high sensitivity in a communications receiver

摘要

A method and circuits are shown for managing the power usage of a receiver circuit by controlling bias current in at least some of the subcircuits of the receiver using a bias current control signal which varies responsive to incoming data signal activity. A circuit is shown wherein an automatic gain control signal controls the gain in a current-mode input amplifier by reducing a bias current in the input amplifier when the activity in the incoming data signal is below an automatic gain control threshold and where the gain of the input amplifier increases responsive to a decreasing level of the bias current. A method is shown wherein the power consumption of a receiver circuit is controlled by generating a bias current control signal which corresponds to the level of activity in a received signal and controlling the bias current, in whole or in part, of at least some of the subcircuits of the receiver using the bias current control signal. Another circuit is shown wherein a data signal monitor circuit is used to monitor the activity in the received data signal and generate an activity signal which controls an adaptive bias circuit. The adaptive bias circuit responds to the activity signal by varying a bias current control signal which controls the bias current in an automatic gain control circuit.