A fundamental block of digital electronics, flip-flops are sequential logic gates used in memory circuits. The computers and communication systems that we’re using today are the courtesy of flip-flops.
Before we discuss the working and application of D-type flip-flops, it’s important to understand why D-type flip-flops are important elements of digital circuits.
A major disadvantage of SR flip-flop is its response to the same input condition, which leads to an invalid state. When the Set and Reset inputs are at 0, the circuit forces both outputs to become 1, over-riding the latching action. To avoid this ambiguity, we connect an inverter between the RESET and SET inputs—creating what we call the D-type flip-flop or delay flip-flop.
Working of D-type Flip-Flops
As discussed above, a D-type flip-flop is nothing but a modified version of an SR flip-flop with a NOT gate. It eliminates the chances of an invalid output, as the two inputs can no longer be at the same state.
In order to prevent the output from changing at every applied pulse, an ENABLE or CLOCK input is added to isolate the stored output. With a clock input, your output only changes on rising edge of the clock.
As the table suggests, it doesn’t matter what signal is present at the input, the output will not change as long as the clock remains at the low state.
Since these circuits are edge-triggered, they only store and output the applied logic as long as the clock signal is high.
Once the state changes to low, the reset and set are held at “1”. This prevents any further changes and stores whatever output was present on the terminal before the clock changed its state. Simply put, the output latches at logic “1” or logic “0”.
Application of D-type Flip-Flops
SR flip-flops are the simplest designs of flip-flops, producing alternating output at the two output terminals. However, the design fails in the implementation of ICs. For an IC to function properly, both signals should reach the input gate at the same time. In practical conditions, however, this isn’t possible as the signal is prone to delays. But for an IC, even a nanosecond delay in the signal causes the entire design to lose its efficiency.
To resolve this issue, designers introduce a delay signal in ICs by using D-type flip-flops. In case of a delayed signal, you can introduce a delay input, causing the second signal to slow down and synchronize with the delayed signal.
Saying that flip-flops have laid the foundation of digital electronics wouldn’t be an understatement. They’re the integral component of memory circuits and are a part of almost every communication system.
If you’re looking for components for your digital circuits, get in touch with ADSANTEC. We house a vast collection of D-type flip-flops. Our collection also includes 4-bit ADC, phase detectors, amplifiers, and filters.
Check out our collection to pick one according to your circuit requirements.