Patent ID: 9136855
Filing Date: 2015-09-15
Classification: H03M

Abstract:
1. An AD converter, comprising: a first oscillation circuit for generating a first pulse signal having a frequency corresponding to a level of a first analog signal; a first counter for counting the first pulse signal generated by the first oscillation circuit; a first arithmetic circuit for generating a first signal corresponding to a change amount of a count value of the first counter at a first predetermined time interval; a second oscillation circuit for generating a second pulse signal having a frequency corresponding to a level of a second analog signal; a second counter for counting the second pulse signal generated by the second oscillation circuit; a second arithmetic circuit for generating a second signal corresponding to a change amount of a count value of the second counter at a second predetermined time interval; a first subtracting circuit for outputting a digital signal corresponding to a difference between the first signal generated by the first arithmetic circuit and the second signal generated by the second arithmetic circuit; an adder circuit for generating a sum signal of the first signal generated by the first arithmetic circuit and the second signal generated by the second arithmetic circuit; a second subtracting circuit for generating a difference signal between the sum signal and a reference signal; and a feedback circuit for amplifying the difference signal and input the difference signal to the first oscillation circuit and the second oscillation circuit.