Patent ID: 7944271
Filing Date: 2011-05-17
Classification: G05F

Abstract:
1. A current source comprising: a first resistor; a first transistor having to first channel terminal coupled in series with the first resistor; a second transistor coupled to the first transistor and configured to have the magnitude of a first current flowing through the channel of the first transistor determined by a voltage difference (ΔV) divided by the value of the first resistor, wherein ΔV is a difference between a first voltage developed across a control terminal of the first transistor and the first channel terminal of the first transistor, and a second voltage developed across a control terminal of the second transistor and a first channel terminal of the second transistor, wherein the first current has a first temperature coefficient (TC); a current mirror configured to mirror the first current, to a second channel terminal of the second transistor to obtain a first mirror current having the first TC flowing into the second channel terminal of the second transistor; and a third transistor configured to inject to second current having a second TC different from the first TC into the second channel terminal of the second transistor to obtain a third current flowing through the channel of the second transistor, wherein the magnitude of the third current is a sum of the magnitude of the first mirror current and the magnitude of the second current, and wherein the third current has a third TC that is a combination of the first TC and the second TC.