Input voltage analogue to digital conversion method - using processor to compare input voltage with two other input reference voltages

摘要

The A/D converter inputs (12,11,10) connected through switch (15) and resistor (16) to the inverting input of the comparator (18). Non inverting input of comparator is connected to a reference voltage (13). A D type flip flop (21), clocked by input (14) and circuit (25), receives input from output of comparator (18). The outputs of D type (21) go to circuit (25) and comparator (18) (via inverting amp (19)). A processing circuit (25) comprises time registers (30-34), impulse counter (27) and processor (29). In partic., a high reference voltage (12) and a low reference voltage (11) each produce a specific number of counts from the processor circuit (25) with one then used with input voltage signal at terminal (10). ADVANTAGE - A/D converters less susceptible to component tolerances.e