ALC CIRCUIT

PROBLEM TO BE SOLVED: To provide the automatic level control(ALC) circuit whose input dynamic range is extended. SOLUTION: A collector current is produced from transistors(TRs) 7, 9 that are connected differentially in response to an input signal fed to the TR 7 and converted into a voltage at TRs 10, 11. A collector voltage of the TRs 10, 11 is fed to TRs 15, 16 that are connected differentially, and a collector current from the TR 15 is converted into an output voltage Vout at a current voltage conversion circuit 18. Through the constitution above, the output signal Vout is increased to increase an emitter resistor re3 of the TRs 15, 16, then am emitter resistor re2 of the TRs 10, 11 is decreased to increase the attenuation rate with respect to an input level. As a result, even when an input signal is increased, an output signal with a prescribed level is obtained.