In this tutorial, we are going to learn about the conversion of Flip- Flip.
In this tutorial we are going to learn about below topics:
- Characteristic table of desired flip-flop.
- Fill the excitation values inputs of given flip-flop for each combination of present state and next state.
Tables of all flip flops are given here
Present State | Next State | SR flip-flop inputs | D flip-flop input | JK flip-flop inputs | T flip-flop input | ||||||||||
Qtt | Qt+1t+1 | S | R | D | J | K | T | ||||||||
0 | 0 | 0 | x | 0 | 0 | x | 0 | ||||||||
0 | 1 | 1 | 0 | 1 | 1 | x | 1 | ||||||||
1 | 0 | 0 | 1 | 0 | x | 1 | 1 | ||||||||
1 | 1 | x | 0 | 1 | x | 0 | 0 | ||||||||
- Simplified expressions for each excitation input. If needed, use K-maps for simplifying.
- Draw the circuit diagram of desired flip-flop according to the simplified expressions.
Conversion of some flip flops
1.SR flip-flop to D flip-flop conversion
Given flip-flop is SR flip-flop and the desired flip-flop is D flip-flop. The characteristic table is given below.
D flip-flop input | Present State | Next State |
D | Qtt | Qt+1t+1 |
0 | 0 | 0 |
0 | 1 | 0 |
1 | 0 | 1 |
1 | 1 | 1 |
SR flip-flop has two inputs S & R. So, excitation values of SR flip-flop for each combination of the present state and next state values. Characteristic table of D flip-flop along with the excitation inputs of SR flip-flop.
D flip-flop input | Present State | Next State | SR flip-flop inputs | |
D | Qtt | Qt+1t+1 | S | R |
0 | 0 | 0 | 0 | x |
0 | 1 | 0 | 0 | 1 |
1 | 0 | 1 | 1 | 0 |
1 | 1 | 1 | x | 0 |
Boolean functions for each input are as below.
S=m2+d3S=m2+d3
R=m1+d0R=m1+d0
K-Maps for S & R are shown below.
Circuit diagram of D- flip flop
- D flip-flop to T flip-flop conversion
Characteristic table of T flip-flop
T flip-flop input | Present State | Next State |
T | Qtt | Qt+1t+1 |
0 | 0 | 0 |
0 | 1 | 1 |
1 | 0 | 1 |
1 | 1 | 0 |
D flip-flop has single input D. So, excitation values of D flip-flop for each combination of the present state and next state values. Characteristic table of T flip-flop along with the excitation input of D flip-flop.
T flip-flop input | Present State | Next State | D flip-flop input |
T | Qtt | Qt+1t+1 | D |
0 | 0 | 0 | 0 |
0 | 1 | 1 | 1 |
1 | 0 | 1 | 1 |
1 | 1 | 0 | 0 |
The boolean function of D is as below.
D=T⊕Q(t)D=T⊕Q(t
Circuit diagram of T flip-flop
- JK flip-flop to T flip-flop conversion
Characteristic table of T flip-flop
T flip-flop input | Present State | Next State |
T | Qtt | Qt+1t+1 |
0 | 0 | 0 |
0 | 1 | 1 |
1 | 0 | 1 |
1 | 1 | 0 |
JK flip-flop has two inputs J & K. So excitation values of JK flip-flop for each combination of the present state and next state values. Characteristic table of T flip-flop along with the excitation inputs of JK flipflop.
T flip-flop input | Present State | Next State | JK flip-flop inputs | |
T | Qtt | Qt+1t+1 | J | K |
0 | 0 | 0 | 0 | x |
0 | 1 | 1 | x | 0 |
1 | 0 | 1 | 1 | x |
1 | 1 | 0 | x | 1 |
Boolean functions for each input are as below.
J=m2+d1+d3J=m2+d1+d3
K=m3+d0+d2K=m3+d0+d2
K-Maps for J & K are shown below:-
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