Analog-to-digital converter.

摘要

A converter for converting an analog signal to a digital pulse comprises a switching capacitor (10) which is charged by a differential analog signal supplied to the switching capacitor (10) over an input circuit (12). The capacitor (10) is discharged over an output circuit (14) with the aid of a constant current supply (44). The charge level of the capacitor (10) is proportional to the analog signal so that the time it takes the capacitor to discharge to a selected low charge level is proportional to the analog signal. This time period is used by a microprocessor (50) to generate a digital pulse having a pulse width equal to the discharge time for the capacitor (10). The microprocessor (50) also selectively connects the input and output circuits (12, 14) to the capacitor (10) for respectively charging and discharging the capacitor.