Digital Potentiometer Schematic

Digital potentiometers are useful when you need to vary the resistance in a circuit electronically rather than by hand.

Digital potentiometer schematic. Controlling a digital potentiometer using spi. Other ways of communicating are through the i 2 c bus and the serial uart bus. Dn is the digital code in decimal form that is used to program the digital potentiometer. The final circuit and schematic are shown in figure e using a 74hc4520 timer chip which contains two 4 bit counters chained together.

And digital pots do not automatically remember the setting. Mechanical potentiometer can also handle significantly more power and wider voltage ranges than digital ones. N is the number of digital potentiometer bits. Its pretty easy to overload a digital pot of this type.

For the mcp4xxxx family of potentiometers the number of bits is eight. Mechanical potentiometer are continuously variable but digital ones are limited to a fixed number of resistance steps. With the mcp4xxxx 8 bit digital potentiometers the pro grammable digital code ranges from 0 to 28 1 or 255. A digital potentiometer digital pot is a variable resistor that is controlled by digital signals instead of by mechanical movement.

This is why i chose a digital potentiometer that has 128 taps so we could make it step up and down with an 8 bit timer. In principle at the heart of a digital potentiometer is a resistor ladder with electronic switches at its every step. All of its outputs are unconnected except for the most significant bit pin. This example shows how to control a analog devices ad5171 digital potentiometer which communicates via the i2c synchronous serial protocolusing arduinos i2c wire library the digital pot will step through 64 levels of resistance fading an led.

The ic x9315 from intersil is a digitally controlled solid state potentiometer which internally possesses an array of resistors wiper switches a controlling system and a non volatile memory. The mcp4131 digital potentiometer communicates via the serial peripheral interface bus or spi bus. The i2c protocol involves using two lines to send and receive data. The spi us was originally created by motorola and is a full duplex serial communication standard that enables simultaneous bidirectional communication between a master device and one or more slave devices.

In this second design we investigate the ic x9315 which is actually a solid state digital potentiometer and could be used exactly like a mechanical potentiometer but through logical supply inputs. In this tutorial you will learn how to control the ad5206 digital potentiometer using serial peripheral interface spi. A serial clock pin scl that the arduino or. Digipots such as the ad5123 and ad5143 offer a nonvolative.

A digital potentiometer is built either from a resistor ladder integrated circuit or a digital to analog converter although a resistor ladder construction is the more common. Citation needed every step on the resistor ladder has its own switch which can connect this step to the output terminal of the potentiometerthe selected step on the ladder determines the resistance ratio of the.