Bias control circuit

摘要

The problem to be solved is to alleviate the distortion characteristic of an amplifier and to prevent the drop in gain with respect to a low-level high-frequency signal. A bias control circuit (10) for controlling the bias of an amplifier (20) which amplifies a high-frequency signal is provided herein with a detector (11) for detecting the envelope of the high-frequency signal, a first bias circuit (12) for supplying a constant bias current to the amplifier (20) and a second bias circuit (14) for supplying a bias current that varies with the variation of the level of the envelope of the high-frequency signal to the amplifier.

主权项

1. A bias control circuit for controlling bias of an amplifier for amplifying a high-frequency signal, provided with:
a detector for detecting an envelope of the high-frequency signal, a first bias circuit for supplying a constant bias current to the amplifier, a second bias circuit for supplying a bias current that varies with variation of a level of the envelope to the amplifier, and a reverse current prevention circuit, interposed in each current path for supplying the bias current from the first and second bias circuit to the amplifier.