To provide a constant-current circuit which has small temperature dependency over a wide temperature range and to provide a triangular-wave generating circuit and a ramp voltage generating circuit which use the constant-current circuit and has no temperature dependency and high precision.

A circuit comprises a voltage generating circuit composed of a reference voltage circuit (a) which is connected between a 1st power source (VDD) and a 2nd power source (VSS) and generates a reference voltage and a temperature characteristic correcting circuit (b) which is connected to the reference voltage circuit and corrects temperature characteristics and a constant-current control circuit (c) which is connected to the temperature characteristic correcting circuit (b) and controls a current flowing to an internal current detecting resistance (R1) with the voltage having temperature characteristics corrected; and temperature characteristics of the voltage generating circuits (a) and (b) and temperature characteristics of the current detecting resistance (R1) are made to cancel each other. Further, this constant-current circuit is used to actualize the triangular wave generating circuit and ramp voltage generating circuit which have no temperature dependency and high precision.