JPH05347516

PURPOSE:To easily provide a monolithic amplifier by providing plural current mirror circuits constituted of transistors having different polarity and a circuit for supplying an idling current to its reference sides, respectively. CONSTITUTION:When there is no signal in an input terminal 24, in a first idling current setting circuit 12, a transistor Q22 is turned on and the same current as the collector current of a transistor Q28 is allowed to flow in transistors Q24, Q29 subjected to current mirror connection to the transistor Q28. The emitter current of a transistor Q23 is increased, and in a well-balanced state to the transistor Q22, the collector currents of the transistors Q22, Q24 coincide with the current Ie of a constant-current source 14. On the other hand, in a second idling current setting circuit 16, as well, the collector currents of transistors Q25, Q27 coincide with the current Ig of a constant-current source 18. Accordingly, since the idling current is determined by the emitter area ratio of transistors Q33, Q35, the variance of a current amplification factor can be decreased.