Patent ID: 7589580
Filing Date: 2009-09-15
Classification: G05F

Abstract:
1. A current reference circuit comprising: a first current generating unit generating a first current having a first current characteristic over a temperature range using an NMOS transistor, wherein the first current generating unit comprises: a second current generating unit generating a second current having a second current characteristic over the temperature range using a PMOS transistor, wherein the first and second current characteristics are distinguished by different first and second current-to-temperature slopes over the temperature range, respectively; a current difference generating unit having input terminals connected to output terminals of the first and second current generating units and generating a current difference between the first and second currents over the temperature range; a third current generating unit having an input terminal connected to an output terminal of the current difference generating unit and generating a third current having a third current characteristic different from the first and second current characteristic over the temperature range, wherein the third current characteristic has a third current-to-temperature slope similar to the second current-temperature slope of the second current by multiplying the current difference by a proportional constant; a reference current generating unit having an input terminal connected to the output terminal of the second current generating unit and generating a reference current by subtracting the third current from the second current; and a final reference current generating unit having an input terminal connected to the output terminal of the reference current generating unit and generating first and second final reference currents in response to the reference current, wherein the first and second final reference currents vary in an inverse relationship one to another.