Patent ID: 7336213
Filing Date: 2008-02-26
Classification: H03M

Abstract:
1. An apparatus for polarity independent precision measurement of an input voltage signal comprising: voltage integrating means for receiving a first positive reference voltage at its first input and connected at its second input to said input voltage signal through a connecting means, said first positive reference voltage being greater in magnitude than said input voltage signal, resetting means coupled to said voltage integrating means for stabilizing the output of said voltage integrating means, a pair of comparators each having a first input terminal connected to the output of said voltage integrating means and having a second input terminal connected to a second reference voltage and a third reference voltage, respectively, said second and third reference voltages being greater in magnitude than said first reference voltage, and time interval measurement means having its two inputs connected to the outputs of said pair of comparators for measuring the time taken for the output of said voltage integrating means to transit between said second reference voltage level and said third reference voltage level, said time interval measurement means also providing complementary outputs for controlling said connecting means and for controlling said resetting means.