Current source type current output circuit using current mirrors

摘要

A current source type current output circuit for applying to a load a current which is proportional to an input includes an amplifier of the type receiving a current and producing a voltage, and a feedback circuit for feeding back an output of the amplifier to an input terminal of the amplifier. The feedback circuit is made up of a first, a second, and a third current mirror circuit, and a first, a second, and a third resistor. An output terminal of the amplifier is connected to an input terminal of the second current mirror circuit via the third resistor and to an input terminal of the first current mirror circuit via a series connection of the first and second resistors. The load is connected to the intermediate point of the serial connection of the first and second resistors. An output terminal of the second current mirror circuit is connected to an input terminal of the third current mirror circuit. Output terminals of the first and third current mirror circuits are connected to an input terminal of the amplifier such that a current which is proportional to an input is fed to the load. A reference terminal of each of the first and second current mirror circuits is connected to a first power source, and a reference terminal of the third current mirror circuit is connected to a second power source.