PURPOSE: To simplify the circuit constitution as well as to obtain a small-sized and light-weighted integrated circuit at low cost by a method wherein the reference bias circuit to be used for an oscillation circuit is commonly used with the bias circuit on the other circuit.

CONSTITUTION: The oscillating part of an oscillation circuit is composed of transistors TR9 to TR12 and a capacitor 13. The operation of this oscillation circuit is determined for every half cycle by the collector currents I1 and I2 of a TR14. Therefore, the oscillation frequency of said circuit depends on the currents I1 and I2, which are determined by the collector current of a TR16. A reference bias circuit B is composed of TR's 16 and 17, a diode 18 and resistors 19 and 20. Also, the reference current of the other controlling circuit, which will be included in the same IC chip, is composed of a TR21 and a resistor 22. Thus, two or more of currents are determined by the reference bias generating circuit, and therefore, the circuit constitution is simplified and unnecessary power consumption can be suppressed when compared with the IC wherein the bias circuit is independently constructed.