Patent ID: 8425744
Filing Date: 2013-04-23
Classification: G01N

Abstract:
1. An ion sensing circuit comprising: an ion sensing element configured for exposure to an electrolytic solution and control of a sensing current through said ion sensing element according to an ion concentration of the electrolytic solution, said ion sensing element including an ion-sensitive field-effect transistor that comprises, said current-to-voltage converter coupled electrically to said ion sensing element for generating a converted voltage from the sensing current, and including a comparator coupled electrically to said current-to-voltage converter for comparing the converted voltage and a threshold voltage to form a comparison result; and a latch coupled electrically to said comparator and said current-to-voltage converter, said latch being configured for sampling the output of said comparator according to a clock signal to generate the digital signal, the digital signal being used by said current-to-voltage converter for converting the sensing current to the converted voltage.