What is the principle and function of digital to analog converter
What is the principle and function of digital to analog converter
Digital to analog converter is a kind of IC products. Digital to analog converter, also known as d/a converter, referred to as DAC, is a device that converts digital quantity into analog.
A converter is a device that converts one signal into another. Signal is the form or carrier of information. In automatic instrument equipment and automatic control system, one signal is often converted into another signal after comparison with standard quantity or reference quantity, so as to connect the two types of instruments. Therefore, the converter is often the intermediate link between two instruments (or devices).
The d/a converter is basically composed of four parts, namely, weight resistance network, operational amplifier, reference power supply and analog switch. Digital to analog converters are generally used in analog-to-digital converters. Analog-to-digital converters, namely a/d converters, referred to as ADC, are devices that convert continuous analog signals into discrete digital signals. The digital to analog converter uses each digit of the digital quantity stored in the digital register to control the analog electronic switch of the corresponding bit respectively, so that the current value proportional to its bit weight is generated on the bit weight network with the digit of 1, and then the current values are summed by the operational amplifier and converted into voltage values.
According to different bit weight networks, different types of DAC can be formed, such as weight resistance network DAC, R-2R inverted T-shaped resistance network DAC and single value current type network DAC. The conversion accuracy of the weight resistor network DAC depends on the reference voltage Vref, as well as the accuracy of the analog electronic switch, operational amplifier and each weight resistor value. Its disadvantage is that the resistance values of each weight resistor are different. When there are many bits, the resistance values are very different, which brings great difficulties to ensure the accuracy, especially for the production of integrated circuits. Therefore, this circuit is rarely used alone in integrated DAC.