COMPENSATION CIRCUIT AND METHOD FOR A POWER TRANSISTOR

摘要

A circuit and method are disclosed for biasing a power transistor to offset unwanted viariations in the operating characteristics thereof. The circuit includes a correction transistor having the same device structure as the structure of the power transistor. In addition, one or more dimensions of the correction transistor is scaled relative to corresponding dimension of the power transistor. The correction transistor is biased so that the ratio of drain currents of the correction transistor and the power transistor is the same as the size ratio thereof. In this way, the output signal of the correction transistor is based upon an unwanted variation in the operating characteristics of the power transistor. The output terminal of the correction transistor is amplified and coupled to the control terminal of the power transistor so that the bias signal applied to the control terminal thereof offsets the unwanted variation in the operating characteristics of the power transistor.