What is latch based clock gating?

Latch based clock gating The latch-based clock gating style adds a level-sensitive latch to the design to hold the enable signal from the active edge of the clock until the inactive edge of the clock.

What is clock gating technique?

Clock gating is a popular technique used in many synchronous circuits for reducing dynamic power dissipation, by removing the clock signal when the circuit is not in use. Clock gating saves power by pruning the clock tree, at the cost of adding more logic to a circuit.

What is clock gating in DFT?

Clock gating is a very common technique to save power by stopping the clock to a module when the module is not operating.

How glitches can be remove through latch?

When the next clock low signal arrives between 2ns to 2.5ns, the EN goes high momentarily and then goes low, and by the end of 2.5ns, the EN goes completely low. So the glitch gets removed by the end of clock cycle.

What is the difference between a latch and a flip flop?

The major difference between flip-flop and latch is that the flip-flop is an edge-triggered type of memory circuit while the latch is a level-triggered type. It means that the output of a latch changes whenever the input changes.

Why is gating the clock bad?

The reason for that rule is that race conditions among the multiple inputs of the combinatory term may cause multiple clock edges (glitches) where you expect only one clock edge. Gating, in this context, means to pass a signal through a logic gate to control it.

What is clock gating in VLSI?

Clock signal is the highest frequency toggling signal in any SoC. This implies that clock path cells would contribute maximum to the dynamic power consumption in the SoC. Power consumption in the clock paths alone contribute to more than 50% of the total dynamic power consumed within modern SoCs.

What’s the difference between power gating and clock gating?

While clock gating focuses on the dynamic power of the circuit by reducing the switching frequency, the power gating focuses on the static/leakage power of the circuit by reducing the flow of current through the circuit.

What is VLSI clock?

In electronics and especially synchronous digital circuits, a clock signal (historically also known as logic beat) oscillates between a high and a low state and is used like a metronome to coordinate actions of digital circuits. A clock signal is produced by a clock generator.

Why do glitches happen?

They can have a wide variety of causes, although the most common causes are errors within the operating system, defects in a piece of software, or problems created by computer bugs or viruses. For example, if a glitch is caused by a computer virus, removing the virus may be the only way to fix the glitch.

What is a clock glitch?

A glitch on a clock signal exposes a chip (or a section of a chip) to asynchronous behavior. A glitch-prone clock signal driving a flip-flop, memory, or latch may result in incorrect, unstable data. Also, some bad design practices that lead to glitches in data are discussed.

Does a latch have a clock?

Both latches and flip-flops are circuit elements whose output depends not only on the current inputs, but also on previous inputs and outputs. The difference between a latch and a flip-flop is that a latch does not have a clock signal, whereas a flip-flop always does.

Is there a problem with above latch based clock gating?

There is another problem with above latch based clock gating. The wire between latch output and AND gate input needs to be carefully routed, else it would result in weird violations. But you know, that’s also been resolved. You just need to find out how, in my STA-2 course. The initial reviews has been real great.

What is clock gating in ASIC design?

Clock gating reduces switching power on clock tree which generally is a large component in power consumed by any chip. Hence while prototyping ASIC on an FPGA, implementation has to take into account what it means to use a clock gate in a design. How does a clock gate work in an ASIC/SoC? Logically speaking, a simple AND gate would be sufficient.

How do you gate a clock to avoid glitches?

However, to avoid glitches on the clock, a latch based clock gating scheme is generally used. The latch works on negedge of the clock and enable is generated on posedge of the clock. Note that enable must be synchronous to the clock that is being gated – a key aspect of this implementation!

Can I configure clock gates in FPGA?

Clock gates are not available as configurable components in FPGAs although FPGAs generally include a limited number of gated buffer on the clock tree. However, the clock tree in FPGAs is already implemented and cannot be changed. Also, clock gates available on the clock tree may not be sufficient to realize clock gates as they are on ASIC.