A converter that converts discrete signals in the form of binary digital quantities into analog quantities based on standard quantities (or reference quantities), also known as a D/A converter, abbreviated as DAC. A common digital to analog converter converts parallel binary digital quantities into DC voltage or DC current. It is commonly used as the output channel of process control computer systems, connected to actuators, to achieve automatic control of the production process. The analog-to-digital converter circuit is also used in the design of analog-to-digital converters using feedback technology. DAC mainly consists of digital registers, analog electronic switches, bit weight networks, summation amplifiers, and reference voltage sources (or constant current sources). Using each digit of the digital quantity stored in the digital register, control the corresponding analog electronic switch, so that the digit 1 generates a current value directly proportional to its bit weight on the bit weight network. Then, the operational amplifier sums the current values and converts them into voltage values. According to the different bit weight networks, different types of DACs can be formed, such as weight resistance network DACs, R-2R inverted T-shaped resistance network DACs, and single valued current type network DACs. The conversion accuracy of the weight resistor network DAC depends on the reference voltage VREF, as well as the accuracy of analog electronic switches, operational amplifiers, and various weight resistor values. Its disadvantage is that the resistance values of each weight resistor are different, and when there are many digits, their resistance values differ greatly, which brings great difficulties to ensure accuracy, especially for the production of integrated circuits. Therefore, this circuit is rarely used alone in integrated DACs. It consists of several identical R and 2R network segments, each corresponding to an input bit. Sections are connected in series to form an inverted T-shaped network. The R-2R inverted T-shaped resistor network DAC is a type of DAC that operates at a faster speed and is widely used. Compared with the weight resistance network, it overcomes the disadvantage of having multiple weight resistance values and large differences in resistance values, as it only has two types of resistance values: R and 2R. Current type DAC switches a constant current source to a resistance network. The constant current source has a high internal resistance, which is equivalent to an open circuit. Therefore, along with electronic switches, it has a relatively small impact on its conversion accuracy. Moreover, because most electronic switches use unsaturated ECL switching circuits, this type of DAC can achieve high-speed conversion and high conversion accuracy