Question $4$

$($a$).$ In industrial boiler's, it is crucial to maintain a constant temperature within the system. The fan speed needs to be adjusted accordingly to achieve the desired temperature level, You are requested to design an industrial boiler inlet fan controller that maintains a constant temperature by adjusting fan speed. Use an embedded circuit with $6$ speed levels, controlled by digital input. Use a temperature sensor that outputs analog voltage $(\backslash (\backslash$mathbf$\{1$ V$\}-\backslash$mathbf$\{5$ V$\}\backslash ))$ corresponding to temperatures $\backslash (\backslash$left$(50^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}-\backslash$mathbf$\{400\}\{\}^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash$right$)\backslash ).$ Stop fan operation at temperature above $\backslash (350^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash )$ and operate at highest speed when temperature drops below $\backslash (50^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash ).$

i$.$ What kind of Converter that you need to use in the design?

$[0\mathrm{.}5$ marks$]$

ii$.$ Specify the resolution, in terms of the number of bits, for the Converter in your design. Justify your answer.

$[$I mark$]$

iii. In your design, you have chosen to implement a Flash Converter. Provide a brief analysis of the advantages and disadvantages of using this type of converter compared to other available conversion techniques.

$[2$ marks$]$

iv$.$ In the design, justify the inclusion or exclusion of a sample and hold circuit in the conversion process.

$[1\mathrm{.}5$ marks$]$

v$.$ In your design, specify the number of comparators that will be utilized in the conversion process.

$[0\mathrm{.}5$ marks$]$

vi$.$ It has been observed that the comparator outputs exhibit a voltage value of $-4\mathrm{.}47$ V and $+4\mathrm{.}41$ V $.$ Provide a solution to mitigate the impact of this deviation on the expected output.

$[1$ mark$]$

vii. Using a higher reference voltage of $5$ V and a lower reference voltage of $0$ V $,$ please provide a detailed schematic diagram of the converter circuit. Clearly label and identify each component used in the design. Additionally, include a proposed solution to the deviation in comparator output voltage previously mentioned in $($vi$),$ it should be clearly indicated the input and output of the circuit.

$[4$ Marks$]$

viii. Calculate the resolution in terms of degree Celsius of the proposed converter.

$[1\mathrm{.}5$ Marks$]$

ix$.$ To improve the resolution of the Converter, one suggestion is to change the lower reference voltage. Justify the optimum value of the lower reference voltage in this context.

$[1$ Marks$]$

$($b$).$ Instead of using the previously proposed setup, it is proposed to utilize the Atmega$328$P microcontroller for the conversion process. Please refer to the provided datasheet $($Figure Q$4($b$))$ of the converter used in the microcontroller to incorporate the relevant information in your design. Assuming the reference voltages as $0$ V and $5$ V calculate the resolution of the converter in terms of voltage.