Patent ID: 7009420
Filing Date: 2006-03-07
Classification: G11C,H04L

Abstract:
1. An input circuit for receiving a signal at an input on an integrated circuit and for assessing the signal with respect to a reference voltage, comprising: a termination circuit for setting a termination voltage, wherein the termination circuit includes a first resistor and a second resistor connected in series between a high voltage potential and a low voltage potential, a first voltage-dependent resistor element having a first resistance gradient connected in parallel with the first resistor; and a second voltage-dependent resistor element having a second resistance gradient connected in parallel with the second resistor; and a control circuit for producing the control voltage, the control circuit comprising a voltage generator circuit for producing a comparison voltage and a differential amplifier; wherein the termination voltage is tapped between the first and second resistors; wherein the resistance values of the first and second resistor elements are controlled by a control voltage to set the termination voltage; wherein the first and second resistance gradients have different arithmetic signs; wherein the first voltage-dependent resistor element comprises a p-channel field effect transistor and the second voltage-dependent resistor element comprises an n-channel field effect transistor; wherein the comparison voltage and the reference voltage are applied to inputs on the differential amplifier; and wherein the control voltage is tapped from an output on the differential amplifier and applied to respective control inputs of the first and second voltage-dependent resistor elements.