Counters in Digital Electronics
This overview of the different types of counters should help you to make a right choice for your application:
With the asynchronous counter, the edge to be counted (rising or falling edge) of the input signal is passed from flipflop to flipflop.
Advantage of this asynchronous counter: Simple structure.
Disadvantage: Runtime delays in the memory elements, because possible changes of the flip-flops are passed on from the beginning to the end of the counter.
The synchronous counter has its stages all clocked together at the same time.
Advantage of the synchronous counter: faster than the synchronous counter, since the trigger signal is present at each FlipFlop simultaneously. In other words, changes in the output of each counter stage occur in “synchronisation” with the clock signal.
Disadvantage: More complex structure