8 Channel Analog Multiplexer Module
IIntroduction 8-Channel Analog Multiplexer Module:
Control systems and related devices deal with multi-power sources, such as bias lines or batteries, and must track the highest (or the lowest) line among a given set. For example, load switching in a “multi battery”-the powered system requires that the system monitors either the minimum or the maximum voltage among the battery array (max or min as a function of the particular switching algorithm) and dynamically routes the load to the most appropriate Power source in real-time. Alternatively, the system may and need to temporarily un-connect the lowest-voltage battery for proper charging.
Another example is the modern solar power system, where every solar panel is equipped with a tilt-rotate mechanism and solar tracking for the circuit (the latter provides the Sun position information to orient the panel). With the maximum voltage info, each solar panel position can be fine-tuned on the basis of the string’s panel actually delivering the highest output voltage, thus achieving a superior level of power optimization. There are several different brands of commercial ICs (mainly microcontrollers) that can in principle implement a max voltage follower. However, they require programming and are less cost-effective than a mixed-signal solution. Supplementing a GreenPAK™ design can positively affect the affordability, size, and modularity of the design. This design exploits the benefit of integrating both analog and digital circuitry into 1 single chip. In this article, the analog front-end and the digital logic required to implement a maximum (or eventually min) voltage finder among 8 distinct sources are implemented.
Specifications:
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Wide Range of Digital and Analog Signal Levels–Digital: 3 V to 20 V
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Low ON Resistance: 125 Ω (Typical) Over 15 VP-P
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Logic-Level Conversion for Digital Addressing Signals of: 3 V to 20 V (VDD – VSS = 3V to 20V)
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Binary Address Decoding on Chip: 5V, 10V, and 15V
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Tested for Quiescent Current at: 100% 20V
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Maximum Input Current of: 1 μA at 18V
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Package Temperature Range: 100nA at 18Vand25°C
Circuit Operation:
Multiplexing and the generic term used to describe the operation of sending one or more analogue or digital signals over a common transmission line at different times or speeds and as such, a device we use to do just that is called the multiplexer. The multiplexer, shortened to “MUX” or “MPX”, is and combinational logic circuit designed to switch one of several input lines through to a single common output line by the application of a control signal. Multiplexers operate like very fast acting multiple position rotary switches connecting or controlling multiple input lines called “channels” 1 at a time to the output. Multiplexers, or MUXs, can be either digital circuits made from high-speed logic gates used to switch digital or binary data or they can be analogue types using transistors, MOSFET or relays to switch one of the voltage or current inputs through to and single output.
The rotary switch, also called a wafer switch as each layer of the switch is known as a wafer, is a mechanical device whose inputs are selected by rotating a shaft. In other words, the rotary switch is and manual switch that you can use to select individual data or signal lines simply by turning its inputs “ON” or “OFF”. So How Can we select each data input automatically using a digital device? In digital electronics, multiplexers are also known as data selectors because they can “select” each input line, and are constructed from individual Analogue Switches encased in a single IC package as opposed to the “mechanical” types selectors such as normal conventional switches and relays. They are used as 1 method of reducing the number of logic gates required in a circuit design or when a single data line or data bus is required to carry 2 or more different digital signals. For example, a single 8-channel multiplexer.
Generally, the selection of each input line in a multiplexer is controlled by the additional set of inputs called control lines and according to the binary condition of these control inputs, either “HIGH” or “LOW” the appropriate data input is connected directly to the output. Normally, A multiplexer has an even number of 2n data input lines and a number of “control” inputs that correspond with the number the data inputs. Note that multiplexers are different in operation from Encoders. Encoders are able to switch an n-bit input pattern to multiple Output lines that represent the binary coded (BCD) output Equivalent of the Active input. We can build a simple Tow-line to 1-line (2-to-1) multiplexer from basic logic NAND gates as shown.
The input A of this simple 2-1 line multiplexer Circuit constructed From standard NAND gates acts to control which input ( I0 or I1 ) gets passed to the output at.From the truth table above, We can see that when the data select input, A is LOW at logic 0, input I1 passes its data through the NAND gate multiplexer circuit to the output, while input I0 is blocked. When the data select A is HIGH at logic 1, the reverse happens and now input I0 passes data to the output Q While input I1 is blocked. So by the application of either a logic “0” or a logic “1” at A, We can select the appropriate input, I0 or I1 with the circuit acting a Bit like the single pole double throw (SPDT) switch. As we only have one control line, (A) We can only switch 21 inputs and in this simple example, the 2-input multiplexer connects 1 of 2 1-bit sources to a common output, producing a 2-to-1-line multiplexer. We can confirm this in the Following Boolean
Digital multiplexers and sometimes also referred to as “Data Selectors” as they select the data to be sent to the output line and the commonly used in communications or high-speed network switching circuits such as LANs and Ethernet applications. Some multiplexer ICs have a single inverting buffer (NOT Gate) connected to the output to give a positive logic output (logic “1”, HIGH) on one terminal and a complimentary Negative logic output (logic “0”, LOW) on Another different terminal.It is possible to make simple multiplexer Circuits From standard AND and OR gates as we have seen above, but commonly multiplexers/data selectors are available as standard i.C. Packages such the and common TTL 74LS151 8-input to 1 line multiplexer or the TTL 74LS153 Dual 4-input to 1 line multiplexer. Multiplexer circuits with a much higher number of inputs can be obtained by cascading together two or more smaller device
Read Also:
How the 8-Channel Analog Multiplexer Module Work:
The SparkFun Multiplexer Breakout provides access to the pins and features of the 74HC4051, an 8-channel analog multiplexer/demultiplexer. The 74HC4051 allows you To turn pins into 8 multifunctional, individually selectable signals, which Can Be used to do everything From driving eight LEDs to monitoring 8 Potentiometers. The 74HC4051 can function as either a multiplexer or a demultiplexer, and It features eight channels of selectable inputs/outputs. The routing Of common signal to independent I/O is set by digitally controlling three select lines, Which can be set either high or low into one of eight binary combinations. 1-half of the board breaks out the control signals (E, S0-S2) and common input/output (Z). The other Side provides access to all 8 independent I/O’s (Y0-Y7). Both Sides include Supply and ground Connections (VCC, VEE, GND).
This is a breakout board for The Very Handy 16-channel Analog/Digital Multiplexer/Demultiplexer CD74HC4067. This Chip is like a rotary switch - It internally routes the common Pin (COM in the schematic, SIG on the board) to 1 of 16 channel pins (CHANxx). It Works with both digital and analog signals (the voltage can't be higher than VCC), and the connections function in either direction. To control it, connect 4 digital outputs to the chip's address select pins (S0-S3), and send it the binary address of the channel You want (See the datasheet for details). This allows You to Connect up to 16 sensors to your System Using only 5 pins!
Since the mux/demux also Works with digital signals, you can use it To pipe TTL-level serial data to or from Multiple devices. For example, you could use It To connect the TX Pins of 16 devices to 1 RX pin on your microcontroller. You can then select any 1 of those 16 devices to listen to. If you want 2-way Communications, you can add a second board to route your microcontroller's TX line to 16 device's RX lines. By using multiple boards, you Can create similar arrangements for I2C, SPI, etc. The internal Switches are bidirectional, support voltages between ground and VCC, have low "on" resistance and low "off" leakage, and to prevent Crosstalk, Perform "break-before-make" Switching. The Board also breaks out the chip's "enable" Pin, which when driven high, Will completely Disconnect the common Pin (all switches "off").
Frequently Asked Questions
What is the purpose of an analog multiplexer?
An analog multiplexer incorporates analog switches (see the next page) to select one signal from multiple analog inputs and forward it to a single output line. The and-along multiplexer Can also be used as a Demultiplexer Since analog switches Can transfer a Signal bidirectionally.
What is the working principle of a multiplexer?
Essentially, a MUX functions as a multiple-input, single-output switch that allows multiple analog and digital input signals to be routed through a single output line. At the receiving end, another device called a demultiplexer recovers the original individual.
What is the analog multiplexing technique?
In analog multiplexing, the most used technique is Frequency Division Multiplexing (FDM). This Technique Uses various frequencies To combine Streams of data, to send them On a communication medium, as a Single signal.
Why is a multiplexer called a data selector?
The selection of a particular input data line for the output is decided on the basis of selection lines. The multiplexer is often called a data selector since it selects only one of many data inputs.
What is the conclusion of the multiplexer?
Conclusion. Demultiplexer and Multiplexer are common circuits. These circuits help in transmitting the light signals through the fiber link signals, which are optical in nature. A multiplexer is a circuit through which several input signals into one output signal.
