Patent ID: 8536933
Filing Date: 2013-09-17
Classification: G05F

Abstract:
1. A circuit for limiting the operating area of a transistor in a constant current source, comprising: a detector having a single input that is coupled to the constant current source, wherein the single input of the detector that is coupled to the constant current source is directly connected to the drain of the transistor included in the constant current source, the detector including an output; and a driver configured for controlling a drain current of the transistor included in the constant current source, wherein the driver has an input connected to the output of the detector and an output connected to the constant current source, the driver comprising a multiplexer and a digital-to-analog converter, wherein the detector and driver are configured such that when a voltage at the drain of the transistor included in the constant current source satisfies a reference condition, the driver causes the drain current of the transistor to decrease, the reference condition determined relative to a maximum safe drain-to-source voltage at a design drain current of the constant current source.