Patent ID: 6816104
Filing Date: 2004-11-09
Classification: H03M

Abstract:
An analog-to-digital converter, comprising:at least one input pin for receiving an analog input voltage; a capacitor for storing charge and producing a voltage across the capacitor; a current source for flowing current through the capacitor for charging the capacitor; a first switch electrically connected between the current source and the capacitor for controlling flow of current from the current source to the capacitor; a comparator for outputting a first comparison value when the analog input voltage and the voltage across the capacitor satisfy a predetermined relationship; a timer for calculating a charging period of time needed for the analog input voltage and the voltage across the capacitor to satisfy the predetermined relationship, wherein the timer starts calculating the charging period of time when the first switch electrically connects the current source to the capacitor for charging the capacitor and stops calculating the charging period of time when the comparator outputs the first comparison value; and a controller for controlling operation of the first switch, for starting the timer when the first switch electrically connects the current source to the capacitor for charging the capacitor, for stopping the timer when the comparator outputs the first comparison value, and for converting the charging period of time calculated by the timer into a digital output voltage.