Circuit for providing a constant current

摘要: Two substantially identical currents (I1,a, I1,b) are subtracted from each other, while being generated by elements (10, 11) in such a way that noise the current value of said two is determined shot noise. The differential current, only noise, supplied to capacitor (13). A second (I2) used charge (22, 29). It periodically whether voltage across first (13) within or outside range bounded (negative and positive values the) 29) which has been charged over same period time. (I1,b, Ib) set dependence on result comparison. signal also serves as control for an element (43) connected constant source. setting thus (I0) delivered source high degree independent temperature sensitivity different components circuit essentially solely ratio similar 11, 20, 27, 43) circuit. By choosing whose appears have dependence, it achieved disappears completely