# D Type Flip Flop : Circuit Diagram, Conversion, Truth Table, Applications

## Level triggered D flip flop

D flip-flop whose output changes according to the input with a high level of the clock pulse is a level triggered D flip-flop, and then the clock level is low, the D flip-flop stays in a hold state.

## D type Edge Triggered flip flop

D edge triggered flip-flop is the flip-flop in which the output can change only with the edge of the clock pulse, regardless of the change in the input. That means the output of the flip-flop changes with the transition of the clock pulse, either from high to low to high.

## D type Edge Triggered flip flop type

Edge triggered D type flip flop can be of 2- types:

The edge triggered flip Flop is also called dynamic triggering flip flop.

## Edge Triggered D flip flop with Preset and Clear

Edge Triggered D type flip flop can come with Preset and Clear; preset and Clear both are different inputs to the Flip Flop; both can be synchronous or asynchronous. Synchronous Preset or Clear means that the change caused by this single to the output can affect the clock pulse; here, it is edge triggered to change with the edge of the clock pulse. Whereas Asynchronous Preset can Clear can change the output at any instant of time.

## Edge Triggered D flip flop Timing Diagram

The given timing diagram shows one positive type of edge triggered d flip flop; there is clock pulse CLK, D the input to the D flip flop, Q the output of the D flip flop; as you can see, the changes in output are happening during the transition of the clock pulse from low to high, because it is a timing diagram of a positive edged D type flip flop.

## Edge Triggered D flip flop Circuit Diagram

The circuit diagram of the edge triggered D type flip flop explained here. First, the D flip-flop is connected to an edge detector circuit, which will detect the negative edge or positive edge of the clock pulse. Then, according to the output of the edge detector circuit, the D flip flop will operate accordingly.

## Rising Edge Triggered D flip flop | Positive Edge D flip flop

The positive edge D type flip flop, which changes its O/P according to the I/P with the +ve transition of the clock pulse of the flip flop, is a positive edge triggered flip-flop. It has high-speed performance with low power consumption, that is because it is widely in use. The positive edge D type flip flop can be represented with a triangle at the D flip-flop block diagram at the clock end.

## Positive Edge Triggered D flip flop Circuit Diagram

The Positive edge triggered D type flip flop circuit can be designed with three latches, where two input latches are adjoining with the clock pulse, one latch is attached with the input data, the circuit is designed in such a way that the output response happens only at positive transition of the clock pulse.

## Positive Edge Triggered D flip flop Timing Diagram

Clock pulse CLK, D the input to the D flip flop, Q the output of the D flip-flop, the changes in output is happening during the transition of the clock pulse from low to high.

## Falling edge Triggered D flip flop | Negative Edge Triggered D flip flop

The D flip-flop, which changes its output according to the input with the -ve. transition of the clock pulse of the flip-flop, is a -ve. edge triggered flip-flop. The negative edge D flip-flop can be represented with a triangle and a bubble at the clock end of the D flip-flop block diagram.

## Negative Edge Triggered D flip flop Circuit Diagram

The -ve edge D flip flop can be designed by adding a -ve edge detector circuit with the clock pulse. The -ve edge detector detects the -ve edge of the clock pulse. According to the O/P of the detector circuit, the rest of the circuit will operate. When there is a negative transition in the clock pulse, the circuit produces output according to the input. Otherwise, the circuit stays in a hold state.

## Negative Edge Triggered D flip flop Timing Diagram

Clock pulse CLK, D the input to the D flip flop, Q the output of the D flip flop, the changes in output is happening during the transition of the clock pulse from high to low; this is the characteristic of the negative edge flip flop.

## Master Slave D flip flop | MS D flip flop

Master Slave flip-flop was designed to make synchronization more predictable. To avoid race around conditions, a master slave flip-flop is also known as the pulse-triggered flip Flop because the response time of the output is equal to the width of the one clock pulse.

Master slave D flip flop can be configured from 2-D flip-flop; each flip-flop is connected to a CLK pulse complementary to each other. One flip-flop as Master and the other act as a slave; when the clock pulse is high, Master operates and slave stays in the hold state, whereas when the clock pulse is low, the slave operates and the Master stays in a hold state. The O/P of the Master is feed into the slave flip-flop as I/P.

## Master Slave D flip flop Circuit Diagram

The master slave D flip flop is designed with NAND gates, configured with 2-D flip-flops, one a latch with the gated circuit, as a master flip-flop, and the other work as a slave flip-flop with a complemented CLK pulse to each other.

## Timing Diagram of Master Slave D flip flop

In the given diagram, a signal of the CLK pulse, D the I/P to the master flip-flop, Qm is the O/P of the master flip-flop, and Q is the O/P of the slave flip flop. Thus, the behavior of a master slave D flip-flop can be observed through its timing-diagram.

## Master Slave Edge Triggered D flip flop

If the master slave circuit is designed with edge triggered D flip flop, or in addition to D flip-flop circuit, there is one edge detector circuit, which detects the edge of a clock pulse. According to the output of the detector, the Flip-flop works. Then the overall circuit is a master slave edge triggered flip flop circuit.

## D flip flop Design

D flip flop can be configured in many ways, like it can be created with NAND gate, NOR gate, Multiplexer, etc. It can be derived from other flip flops like JK flip flop, SR flip flop, or T flip flop. It can be designed with the help of many different combinations of the circuit with the clock.

## D flip flop circuit diagram using NAND gates

The D flip flop can be designed with NAND gate only, here one SR latch is designed with NAND is gated with two more NAND gates, and the clock pulse is input to the gated NAND with Data input, where one NAND gate D as input and the other NAND gate gets D compliment as one input. And according to the gated output, the SR latch is processed. The resulting circuit is a D flip flop circuit.

## D flip flop using NOR gate

The D flip flop can also be designed with NOR gates; here, three SR latches with clock pulse are used to develop the D flip-flop. The two input SR latch create the D and D complement output separately, and that output is feed into the third latch, which produces Q and Q-compliment as output.

When there is no clock pulse, the initial latches get locked with the current state because of the interconnections, which cause the whole flip Flop to put on a hold state; regardless of the change in input data, the output cannot change.

## Design D flip flop using Transmission Gate

The D flip flop can be designed with a Transmission gate, which reduces the complexity of the circuit as it reduces the number of transistor counts. When LOAD =0, the Latch stores the data input; when LOAD = 1, the latch is transparent. The transmission gate also helps to reduce the overall circuit size.

## D flip flop using MUX Explanation

A D flip flop can be designed with a single multiplexer(MUX), data ‘D’ is an input to the MUX, and the other input of the MUX is the feedback of the multiplexer output Q to itself’s input, the clock signal is acting as select line, If the clock (CLK) = one then the output of the MUX is D, otherwise the output of the MUX remain the past output Q.

## Conversion of JK flip flop to D flip flop

D will be the external input to the JK flip flop, and JK flip flop is the universal flip Flop; we can design D flip-flop from the JK flip flop if we connect the K input of the JK flip flop with an inverter to the J input. Then the resulting circuit will be D flip-flop with I/P as D and O/P as Q and Qbar.

Where Qn+1 means the next output state and Qn means the present output state in the conversion table.

## D type flip flop Frequency Divider | D flip flop Clock Divider

A frequency divider is a digital circuit that divides an input frequency by a required factor. One such frequency divider is designed with a D flip flop, which divides the input clock frequency by two. One inverted feedback is from output Q to the input D is forming this frequency divider circuit.

### Divide by 3 Circuit using D flip flop

The given circuit divides the input frequency by three. In this circuit there is 2 D flip-flop is used, and one NOR gate, which forms the resulting circuit, divides the input frequency by three.

## Phase Detector using D flip flop

A phase frequency detector is a circuit used to detect the difference of frequencies and phase of two given inputs. The UP signal is generated when the clock signal is slower than the reference clock signals. The down signal is generated when the clock signal is faster than the reference clock.

The phase frequency detector can be designed with two D flip-flop as shown in the above figure; both the flip flop has different clock frequencies as input, and the reset of the flip flops are connected with a NAND gate whose input is the Down and Up signal.

## Frequency Multiplier using D flip flop

The frequency multiplier is a digital circuit that generated the multiple of the input clock frequency signal.

The circuit can be designed with the D flip-flop and even the number of inverted in the feedback line. The feedback is started from the output Q and goes to the NOR gate, which is attached with the clock input of the Flip Flop. The multiplier circuit output depends on the delay produced by the inverters; with different delays, we can produce different frequencies as output.

## D flip flop Oscillator

The oscillator is a circuit that generates repeated and alternating waveforms. The oscillator can be designed with D flip-flop, where D flip-flop must be in a toggle, so whenever it gets a high input, the output value should toggle; for creating toggle flip flop from d flip flop, the complementary output of the D flip-flop is feedback to the Data input of the D flip-flop.

## D flip flop Register

A register is a group of flip flops that can store more than one bit at a time, depending on the number of flip flops in the register.

## Quad D type flip flop 74175 | Quad D flip flop 7475

Quad d flip flop is available in Ingratiated circuitry, which has 16 pins. It has a 4 d flip flop with separate input(D) and output ( Q and Qbar ) pins. The remaining pins are one ground, one clear, one clock, and one voltage supply pin. Its function is equivalent to the TTL 74175. It contains edge triggered D flip flop.

## Hex D type flip flop

It is a type of d flip flop available in IC, which contains 6 d flip flops each has different input and output pin in the integrated circuit. Thus, it has 16 pins with one clock pin, one ground pin, one voltage supply pin, and one clear pin.

## 8 bit Octal D flip flop

Octal d type flip flop is commercially available as an Ingratiated circuit. It contains 20 pins, which have three-state output. All the flip-flops are mainly controllable by the clock and enable pin. Each flip Flop has different input (D) and output (Q) pins. The remaining pins are one clock pin, one ground pin, one voltage supply pin, one clear pin. This Ic is used to design a storage register, pattern generator, etc.

## 16 bit D flip flop

It is a type of D flip flop available in IC; mainly a 16-bit edge triggered d flip flop with three-state output, designed for driving highly capacitive or low impedance load. It can be used as a 16 bit flip Flop, also can be used as two 8 bit flip flops. It has 48 pins, whereas each flip Flop has separate pins for input and output; two clock pins and two enable pins. It is used in designing buffer registers, input or output ports, bidirectional buses, etc.

Sneha Panda

I have graduated in Applied Electronics and Instrumentation Engineering. I'm a curious-minded person. I have an interest and expertise in subjects like Transducer, Industrial Instrumentation, Electronics, etc. I love to learn about scientific researches and inventions, and I believe that my knowledge in this field will contribute to my future endeavors. LinkedIn ID- https://www.linkedin.com/in/sneha-panda-aa2403209/