4 Bit ADC

This ADC uses successive approximation. First the counter counts up which increases the output voltage of the DAC. This voltage is then compared to the measurement voltage. If it is still below the measurement voltage the up counting is continued. If the DAC voltage overshoots the measurement voltage a comparator reverses the counting direction and the DAC voltage decreases. As the DAC voltage dips below the measurement voltage again the counting direction is again reversed and so on and so forth. The flickering bit is often discarded because no useful information cab be derived from it. To calculate the measured voltage divide the counter digit by the word size of the DAC and multiply by the max DAC voltage. The bigger the word size the greater the accuracy.

published 10 years ago