What is the working principle of digital potentiometer

Digital potentiometer, also known as numerical control device, is a new type of CMOS integrated circuit for mixed digital and analog signal processing.

The digital potentiometer is controlled by digital input and generates analog output.

According to different digital potentiometers, the maximum tap current can range from hundreds of microamps to several milliamps. The digital potentiometer adopts numerical control to adjust the resistance value, which has the remarkable advantages of flexibility, high adjustment accuracy, no contact, low noise, not easy to damage, anti vibration, anti-interference, small size, long service life and so on. It can replace the mechanical potentiometer in many fields.

Digital potentiometer is a semiconductor integrated circuit, which cancels the resistance substrate and brush. The advantages are that there is no noise with high adjustment accuracy, and there is no long-life mechanical wear automatic control system, which can realize the correct measurement of angle position, and can also realize the output adjustment function by driving the rotating shaft by using the output feedback signal and the characteristic that the angle change is linear proportion.

However, the digital positioner has inherent shortcomings, such as large rated stop error, large temperature coefficient, narrow pass frequency band, small allowable current at the sliding end (generally 1-3ma), which greatly limits its application. There are many kinds of digital potentiometers with different functions. According to the number of digital spotters inside the chip, it can be divided into single channel, double channel, four channel, six channel, etc; According to the change characteristics of resistance value, it can be divided into linear and nonlinear (logarithmic and exponential); According to the serial interface bus, it can be divided into I2C bus, SPI bus, single line bus, etc.

The digital potentiometer eliminates the resistance substrate and brush, and its advantages are: high adjustment accuracy; No noise, very long working life; No mechanical wear; For the automatic control system, the accurate measurement of the angle position can be realized, and the output adjustment function can be realized by driving the rotating shaft by using the characteristic that the output feedback signal is linearly proportional to the angle change.