1. Design Example “Date of Birth Problem”

2. Combinational Logic Application
Design a combinational logic circuit that has three inputs and seven outputs. As the inputs count from 000 to 111, the seven outputs will generate the required logic to display your date of birth on a seven segment display.
Date of Birth
7-Segment Display
Driver Logic Circuit a b c d e f g X Y Z

3. Circuit Inputs
X Y Z X
Display
Example:
If your date of birth is July 23, 1961, the circuit will display the output shown to the right The last two outputs are don’t cares.

4. Common Anode LED Display 1 +5 V Segment Is OFF ! Segment Is ON !
Segment Is ON !
Logic For
Segment A
270 - 330

5. X a g f b d e c a g f b d e c a g f b d e c a g f b d e c a g f b d e
X Y Z X
a b c d e f g
Display a g f b d e c a g f b d e c a g f b d e c a g f b d e c a g f b d e c a g f b d e c
x x x x x x x
x x x x x x x

6.
X Y Z X
a b c d e f g
x x x x x x x
Display
Logic For
Segment “a”
X X
Y Z 1 x
X Z
a = X Z

7. Boolean Equations for 7 Segments
a = X Z
b = X Z
c = Y Z
d = Y Z
e = Z
f = Y + Z
g = X Y + Y Z

8. DOB 7-Segment Display Driver Circuit
7408
AND Gates
7404
Inverters
7432
OR Gates

9. 7-Segment LED Display

10. Assignment
Design a Date-of-Birth 7-Segment Display Driver Circuit for your birth date. Include the truth table, K-Maps & logic design.
Simulate your design using circuit design software.
Breadboard and test your design.