Temperature compensation for internal inductor resistance

摘要

A compensation circuit compensates for the variation in the internal resistance of a multi-track inductor over temperature. The compensation circuit includes a dummy inductor that has the same temperature dependent resistance as that of the multi-track inductor that is to be compensated. A first field effect transistor is placed in series with the multi-track inductor that is to be compensated, and a second field effect transistor is placed in series with the dummy inductor, where the gates of the FETs are tied together. A control circuit provides a constant current for the dummy inductor and detects any changes in voltage of the dummy inductor over temperature. The control circuit includes a feedback loop that controls the gate voltage of both first and second FETs so as to compensate for the temperature dependent inductor resistance variations of both the dummy inductor and the multi-track inductor that is to be compensated.