PURPOSE: To attain the titled circuit suitable for circuit integration with low power consumption, by obtaining a large current output at a large signal of an output of a signal source without increasing an output current of a constant current source, for attaing the extraction of the large output current with a less non-signal current.

CONSTITUTION: When the output signal from a signal source 21 is a large signal at the positive polarity, an emitter potential of a transistor (TR)Q16 is decreased, a TRQ17 is turned off, and the TRQ16 is driven as a common base amplifier. Then, a TRQ18 is driven, and a collector current is summed to an output current from the constant current source 30 and led to an output terminal, where a large current than the output current of the constant current source 30 is obtained. Thus, since a large current output is obtained when the output of the signal source 21 is a large signal without increasing the output current of the constant current source 30, a current flowing at non-signal or a small signal is less, allowing to attain the low power consumption and to make the circuit suitable for circuit integration.