Patent ID: 6529355
Filing Date: 2003-03-04
Classification: G01R,H02H

Abstract:
An input protection circuit, comprising:an input for receiving an input signal; a first transistor coupled to the input; a second transistor coupled in series to the first transistor; a first detection circuitry coupled to the first transistor, wherein the first detection circuitry is operable to: detect a level of the input signal; deactivate the first transistor if the level of the input signal exceeds a first voltage threshold; a second detection circuitry coupled to the second transistor, wherein the second detection circuitry is operable to: detect the level of the input signal; deactivate the second transistor if the level of the input signal exceeds a second voltage threshold; and a current shunt coupled to the second transistor; wherein the input protection circuit operates to prevent the input signal from being provided to the current shunt if the level of the input signal exceeds either the first or second voltage threshold; wherein the first detection circuit and the second detection circuit are each operable to be powered using an enhancement voltage source.