What are the common sources of power dissipation in RTL design and how can you reduce them?

1 Dynamic power

Dynamic power is the power consumed by the switching activity of the transistors in the circuit. It depends on the clock frequency, the supply voltage, the capacitance of the nodes, and the switching probability of the signals. To reduce dynamic power, you can use techniques such as clock gating, voltage scaling, power gating, and data encoding.

2 Static power

Static power is the power consumed by the leakage current of the transistors in the circuit. It depends on the technology, the temperature, the supply voltage, and the transistor size. To reduce static power, you can use techniques such as multi-threshold CMOS, body biasing, transistor stacking, and power gating.

3 Short-circuit power

Short-circuit power is the power consumed by the current that flows between the supply and the ground when both the pull-up and the pull-down networks are partially on during a logic transition. It depends on the rise and fall times of the input signals, the supply voltage, and the transistor sizes. To reduce short-circuit power, you can use techniques such as slew rate control, gate sizing, and voltage scaling.

4 Glitch power

Glitch power is the power consumed by the spurious transitions of the signals due to the delay mismatch between different paths in the circuit. It depends on the logic depth, the fanout, the gate delay, and the switching probability of the signals. To reduce glitch power, you can use techniques such as path balancing, glitch filtering, and data encoding.

5 Memory power

Memory power is the power consumed by the memory elements in the circuit, such as registers, latches, and RAMs. It depends on the memory size, the access frequency, the read/write ratio, and the data pattern. To reduce memory power, you can use techniques such as memory partitioning, memory banking, memory compression, and memory gating.

6 I/O power

I/O power is the power consumed by the interface between the circuit and the external environment, such as pads, drivers, receivers, and buffers. It depends on the I/O standard, the I/O voltage, the I/O frequency, and the I/O loading. To reduce I/O power, you can use techniques such as I/O voltage scaling, I/O frequency scaling, I/O termination, and I/O encoding.