CURRENT SOURCE AND METHOD FOR GENERATING CURRENT

摘要

PROBLEM TO BE SOLVED: To prevent an output current from being affected by variations of temperature and an external voltage source by adding two currents which are opposite in temperature coefficient and supplying the current. SOLUTION: The current source 10 has a band-gap reference circuit 12, supplies a temperature-dependent current IBGR increasing as the temperature rises, and also supplies a temperature-dependent voltage VBGR to one input side of an amplifier 14 in response to the current IBGR. The drain of an MOSFETT1 connected to the output side of this amplifier 14 is connected to the other input side of the amplifier 14 to constitute a negative feedback mechanism. Further, a current mirror part 26 outputs a variable power current nIBGR to an addition node in response to the current IBGR supplied in the circuit 12. The current IR derived by dividing the voltage VBGR by a positive temperature coefficient resistance R is also supplied to the addition node 22. Consequently, the current source 10 supplies an output current IREF=nIBDR+IR to the addition node 22 to eliminate the influence of variations of the temperature T and power source 18.