The standard electric current control circuit, temperature compensation functional equipped quartz oscillator control IC, being the standard electric current control circuit which

摘要

PPROBLEM TO BE SOLVED: To provide a reference current control circuit, crystal oscillator control IC with temperature compensation function, crystal oscillator, TCXO module, and portable telephone set, in which variations of an output frequency generated at start-up, can be stabilized. PSOLUTION: A reference current control circuit 500 comprises a temperature sensor 21, a voltage-current conversion circuit 22, a cancel circuit 23, a switch 24, a time constant circuit 25 for controlling the switch 24, and an adder circuit 26. When a reference temperature is defined as Tr, the chip surface temperature of an LSI is elevated by ΔTr at start-up, so that the collector/base voltage V1(t) of a diode 1 is varied. The cancel circuit 23 outputs a voltage V2(t) opposite to the fluctuation of the voltage V1(t), the voltage V2(t) is added to V1(t) by the adder circuit 26, becomes a stable voltage V3(t) and is input to the base of an input transistor 3 in the voltage-current conversion circuit 22. After the lapse of a fixed time, the switch 24 between the cancel circuit 23 and the adder circuit 26 is turned off by the time constant circuit 25. PCOPYRIGHT: (C)2008,JPO&INPIT