Patent attributes
A bias circuit includes: a first transistor having a base terminal grounded via a resistor, and a collector terminal connected to a first power supply port via an adjustment resistor; a second transistor having an emitter terminal connected to the base terminal of the first transistor, and a base terminal connected to the collector terminal of the first transistor; a third transistor having a base terminal connected to the base terminal of the first transistor, and a collector terminal connected to the first power supply port via an adjustment resistor; and a fourth transistor having a base terminal connected to the collector terminal of the third transistor, a current being taken out from the emitter terminal of the fourth transistor. This arrangement makes it possible to suppress a consuming current and output a bias current that is more stable against a temperature change and/or a power supply voltage change.