Abstract: When digital systems are used in real-world applications, it is often necessary to convert an analog voltage level to a binary number. The value of this number is directly or inversely proportional to the voltage. The analog to digital converter (ADC) using FPGA , an analog comparator, and a few resistors and capacitors.

This ADC uses the Delta-Sigma Digital to Analog converter (DAC) The analog level is determined by performing a serial binary voltage search, starting at the middle of the voltage range. For each complete sample, only the upper bit of the DAC input is initially set, which drives the reference voltage to midrange. Depending on the output of the comparator, the upper bit is then cleared or it remains set, and the next most significant bit of the DAC input is set. This process continues for each bit of the DAC input.