Converting from analog to digital requires the idea of converting from digital to analog. So we should learn about the transition from digital to analog first.
Convert from digital to analog
Conversion from digital to analog is basically a method of taking the equivalent or proportional decimal value of digital or binary code. Which will be current or voltage. As we know, IC is an active device. In other words, if you want to do any work with it, you have to turn it on with a DC voltage first. However, the DC voltage that we turn on, it can not output more. For example, if we turn it on with a 16V DC voltage sump on pins 4 and 7 of an amplifier Op-amp, the amplifier will give a maximum output of 16V. Which is called full-scale output.
Register or any other digital system is used to give digital input to DAC IC. The figure shows a four-bit DAC. As we know, 2 ^ 4 = 16 different combinations are possible for 4 bit binary. We can give 16 different binary inputs on the four pins D, C, B and A in the figure. Different outputs are available for each of which is equal to the decimal value of the binary inputs (Figure 1.7 (b)). In the case of each DAC, the output will be equal to the decimal value of the binary code, but not. However, the output will be proportional to the decimal value of the binary input. That is,
Analog output: The decimal value
of digital input
Analog output = K × digital
input
V_out = K × V_in
Where K is a proportional
constant. Which depends on the DAC we are using. If the analog output is
current, then the unit of the ampere is K. If the analog output is voltage, then
the unit voltage of K. If we know the K value of any type of DAC, we can determine
the output for any digital input.
Input and output
For 4-bit binary input, we got 16 combinations that give different outputs. The output or decimal value here is based on the position value of the input bit.
Like- just
- If the input of pin A is binary input 1, the output = 1V
- If the input of pin B is binary input 1, the output = 2V
- If the input of pin C is binary input 1, the output = 4V
- If the input of pin D is binary input 1, the output = 8V
When the input of all other pins is 0. Which indicates the value of their position.
Written
Jeion Ahmed
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