Amplifier circuit with temperature compensation
AssigneeU.S. Philips Corporation
InventorHendrik Boezen
Life of this patent
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Abstract
A temperature compensated amplifier circuit includes a control transistor and an output transistor having a control electrode coupled to the main current path of the control transistor. The control electrode of the output transistor is also coupled to a current supply element which is connected in series with the main current path of the control transistor for supplying a bias current whose variation as a result of thermal cooupling between the current supply element and the output transistor is smaller than the variation of the part of the bias current through the main current path of the control transistor as a result of thermal coupling between the control transistor and the output transistor.
Claims19
An amplifier circuit comprising:
- a control transistor, an output transistor whose control electrode is coupled to a main current path of the control transistor, and means coupling the control electrode of the output transistor to a current supply circuit connected in series with the main current path of the control transistor, the current supply circuit supplying to the output transistor a bias current whose variation as a result of thermal coupling between the current supply circuit and the output transistor is smaller than the variation of the part of the bias current flowing through the main current path of the control transistor as a result of thermal coupling between the control transistor and the output transistor.
A temperature compensated amplifier circuit comprising:
- an output transistor having a control electrode,
- a current supply circuit and a control transistor connected in series circuit between first and second terminals of a supply voltage,
- means coupling the control electrode of the output transistor to a node in said series circuit whereby the current supply circuit supplies a bias current having a first current part that flows to the control electrode of the output transistor and a second current part that flows to the control transistor, and
- means for providing a thermal coupling relationship between the output transistor and the control transistor and between the output transistor and the current supply circuit such that a variation in the first current part as a result of the thermal coupling between the output transistor and the current supply circuit is smaller than a variation in the second current part as a result of the thermal coupling between the output transistor and the control transistor.
Dependencies are inferred from the claim text.