Patent ID: 8779827
Filing Date: 2014-07-15
Classification: G01R

Abstract:
1. An integrated circuit, comprising: a high voltage transistor having a first terminal, a second terminal and a control terminal, wherein the first terminal is coupled to sense a high voltage terminal of the integrated circuit and the control terminal coupled to an internal regulated voltage terminal of the integrated circuit, wherein a regulated voltage at the internal regulated voltage terminal is regulated with respect to a ground terminal of the integrated circuit and is substantially less than a high voltage that the high voltage terminal is adapted to withstand; a logic gate having an input terminal and an output terminal, wherein the logic gate is coupled to be powered from the internal regulated voltage terminal, wherein the logic gate has an input threshold voltage that is less than the regulated voltage, wherein the input terminal of the logic gate is coupled to the second terminal of the high voltage transistor, wherein the output of the logic gate is coupled to indicate that a voltage sensed between the high voltage terminal and the ground terminal is less than the input threshold voltage of the logic gate; and a clamp circuit coupled between the high voltage terminal and the ground terminal, wherein the clamp circuit conducts current when the voltage sensed between the high voltage terminal and the ground terminal is less than the input threshold voltage of the logic gate.