US Patent 7667449 Constant current supply circuit capable of being trimmed

To provide a constant current circuit which is capable of not only acquiring characteristics of various sorts of electric circuits even before a trimming adjustment is carried out, performing the trimming adjustment based upon the acquired characteristics, performing trimming processes to both the constant current circuit and a load collectively, and performing an adjustment of a constant current with high precision, but also capable of reducing a total number of manufacturing steps so that a production cost can be lowered, as compared with that of a conventional constant current circuit.