MULTI-STAGE DIFFERENTIAL AMPLIFIER CIRCUIT WITH MEANS FOR COMPENSATING THE TEMPERATURE DRIFT CONSTANT CURRENT SOURCE TRANSISTOR

摘要

A multi-stage differential amplifier circuit comprises a preceding stage differential amplifier and a succeeding stage differential amplifier which are direct-coupled in unbalanced configuration. A variation in the DC level at an output of the amplifier circuit due to the temperature drift of a constant current source transistor in the preceding stage differential amplifier is compensated by a bias circuit connected to the base of one of differential transistors in the succeeding stage differential amplifier. The compensation bias circuit includes a current source transistor the base of which is connected, together with the base of the current source transistor in the preceding stage differential amplifier, to a common drive voltage source.