Patent ID: 8665005

Claim:
An apparatus comprising: a current source having an output current, wherein the output current varies at a first rate with a change in a temperature of the current source; a first transistor having a source, a drain and a gate, wherein the source of the first transistor is connected to the current source; a second transistor having a source, a drain and a gate, wherein the source of the second transistor is connected to (i) the drain and the gate of the first transistor, and (ii) the gate of the second transistor; and a buffer connected to the source of the first transistor, wherein a transconductance value, of a combination of the first transistor and the second transistor, varies at a second rate with the change in the temperature of the current source, wherein the second rate is based on the first rate, the current source comprises an input and a variable resistance, the current source is configured to (i) for a first scan of the current source, receive a first reference voltage at the input of the current source, and (ii) output a first current in response to the first reference voltage, the current source is configured to (i) for a second scan of the current source, receive a second reference voltage at the input of the current source instead of the first reference voltage, and (ii) output a second current in response to the second reference voltage, and the variable resistance is configured to, for a predetermined temperature of the current source, be adjusted from a first resistance to a second resistance to match the second current to the first current.