Patent ID: 7965129
Filing Date: 2011-06-21
Classification: G05F

Abstract:
1. A temperature compensated current reference circuit comprising: a differential amplifier having two differential inputs and a differential amplifier output; a first feedback transistor with a control electrode coupled to the differential amplifier output, the first feedback transistor providing a coupling of a first voltage reference node to a first one of the two differential inputs; a second feedback transistor with a control electrode coupled to the differential amplifier output, the second feedback transistor providing a coupling of the first voltage reference node to a second one of the two differential inputs; a first temperature dependent conductor coupling the first one of the two differential inputs to a second voltage reference node; a primary reference resistor; a second temperature dependent conductor having a conductivity that is greater than a conductivity of the first temperature dependent conductor for a given temperature, wherein the second temperature dependent conductor is connected in series with the primary reference resistor and the second temperature dependent conductor and primary reference resistor couple the second one of the two differential inputs to the second voltage reference node; an output current control transistor having a control electrode and one other electrode coupled together and a third electrode coupled to the first voltage reference node, a secondary reference resistor; a conductivity change sensing transistor connected in series with the secondary reference resistor, the conductivity change sensing transistor having a control electrode coupled to the second one of the two differential inputs, wherein the conductivity change sensing transistor and secondary reference resistor couple the control electrode of the output current control transistor to the second voltage reference node; and a temperature compensated current reference output circuit having a current reference transistor and two control inputs, a first one of the control inputs is coupled to the differential amplifier output and a second one of the control inputs is coupled to the control electrode of the output current control transistor.