Patent ID: 7298182
Filing Date: 2007-11-20
Classification: G11C,H03K

Abstract:
1. A comparator circuit, comprising: a current source; a differential amplifier for providing an output voltage signal indicative of a voltage level of an input voltage signal applied to a first input transistor relative to a reference voltage signal applied to a second input transistor, wherein the first and second input transistors are coupled at a common node; a switching transistor positioned to prevent the flow of current between the current source and the common node in response to a switching voltage signal applied to the switching transistor, wherein the switching voltage signal is derived from the input voltage signal; and a precharge transistor to precharge the input voltage signal to a predetermined value; wherein the switching transistor is a NMOS transistor and the switching voltage signal is derived from the input voltage signal such that the switching transistor prevents the flow of current between the current source and the common node when the input voltage signal falls below a threshold voltage and wherein the precharge transistor is responsive to a voltage signal derived from the output voltage signal.