Patent ID: 6717471
Filing Date: 2004-04-06
Classification: H03G

Abstract:
An automatic gain adjustment circuit comprising:an amplifying element having a control electrode, a ground electrode, and an output electrode; a load connected to the output electrode; an output terminal formed at a connection point between the output electrode and the load; a bias circuit connected to the control electrode to control a gain of the amplifying element; a variable current source connected to the output electrode to control a DC output voltage at the output terminal; a gain detection circuit connected to the output terminal to detect the gain of the amplifying circuit; and a DC output voltage detection circuit for sensing the DC output voltage, wherein the gain of the amplifying circuit and the DC output voltage at the output terminal thereof are adjusted to have respective specified values by controlling the bias circuit with an output of the gain detection circuit and controlling the variable current source with an output of the DC output voltage detection circuit.