| US 7,616,059 B2 | ||
| Temperature compensation of small signal gain of an amplifier stage | ||
| Christian Grewing, Sollentuna (Sweden); Detlev Theil, Bromma (Sweden); and Stefan Van Waasen, Kolbermoor (Germany) | ||
| Assigned to Infineon Technologies AG, Munich (Germany) | ||
| Filed on Apr. 18, 2007, as Appl. No. 11/788,036. | ||
| Claims priority of application No. 06008126 (EP), filed on Apr. 19, 2006. | ||
| Prior Publication US 2008/0231363 A1, Sep. 25, 2008 | ||
| Int. Cl. H03F 3/45 (2006.01) | ||
| U.S. Cl. 330—256 [330/283] | 6 Claims |
| 1. A differential amplifier circuit comprising:
an amplifier stage comprising a first and a second transistor, the gates of which are connected to differential input terminals
of said amplifier stage, and
a temperature compensation circuit comprising a third and a fourth transistor and a constant current source connected to the
respective sources of said third and fourth transistors and providing a current that is dependent on an operational temperature,
wherein the drain of said third transistor is connected to the source of said first transistor and the drain of said fourth
transistor is connected to the source of said second transistor, and
wherein the gate of the third transistor is connected only to the gate of the fourth transistor and the gate of the fourth
transistor is connected only to the gate of the third transistor for providing a varying feedback resistance by means of the
current source independent from the operating temperature thereby compensating for variations of the resistance of said first
and second transistors.
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