Analog/digital conversion circuit

摘要

According to one embodiment, a first AD converter converts a first voltage into a first digital signal. A voltage/time conversion circuit acquires a residual corresponding to a difference between the first voltage and a result of having converted the first digital signal into an analog signal and converts the residual into a time signal according to a voltage in a first capacitor. A time/voltage conversion circuit converts the time signal into a voltage signal according to a voltage in a second capacitor. A second AD converter converts the voltage signal into a second digital signal. A digital processing circuit outputs a third digital signal to adjust a current value of first or the second current sources based on the second digital signal.

主权项

1. An analog/digital conversion circuit comprising:
a setting circuit which fixes an input to a first voltage; a first analog/digital converter which converts the first voltage into a first digital signal; a voltage/time conversion circuit comprising a first capacitor and a first current source which supplies an electric current to the first capacitor, the voltage/time conversion circuit acquiring a residual signal corresponding to a difference between the first voltage and a result of having converted the first digital signal into an analog signal, and converting the residual signal into a time signal in accordance with a voltage charged in the first capacitor; a time/voltage conversion circuit comprising a second capacitor and a second current source which supplies an electric current to the second capacitor, the time/voltage conversion circuit converting the time signal into a voltage signal in accordance with a voltage charged in the second capacitor; a second analog/digital converter which converts the voltage signal into a second digital signal; and a digital processing circuit which outputs a third digital signal to adjust a current value of at least one of the first current source and the second current source based on the second digital signal.