The low-power ASICs are now a must-have in today’s tech-driven world due to their contribution to the eco-friendliness of portable devices, IoT solutions, automotive electronics, and high-performance data centres. These purpose-built chips are designed to conserve power, extend battery life, and mitigate heat issues without compromising performance. To accomplish such goals, many chip design companies are switching to the best technologies that, at the same time, maximize efficiency and reduce power usage in recent chipmaking processes. Their function is crucial in the context of the growing demand for intelligent, interconnected, and environmentally friendly systems.
The Best Strategies for Low-Power ASIC Designing
Creating a low-power application-specific integrated circuit (ASIC) is essential in today’s electronics, in battery-powered and portable devices. The focus is to reduce both dynamic power, which the circuit consumes while active, and static power, which the circuit consumes when idle due to leakage currents. Here are the main strategies:
1. Clock Gating: Clock signals play an important role in power dissipation in the form of a constant switching signal, transistors being turned on and off, and thus drawing power from the supply. Also, clock gating selectively turns off clock signals to parts of the circuit that are not in use at a given moment. For instance, when a section of the chip, such as a video decoder, is set to inactive, its clock may be gated off to prevent uneconomic switching and hence save power. Moreover, this approach is highly effective as it prevents a whole logic block from consuming dynamic power; however, it should be carefully addressed to prevent glitches and timing problems.
2. Power Gating: In contrast to clock gating, which aims at dynamic power, power gating is directly concerned with lower static or leakage power. It essentially means clamping the voltage in a circuit block. This is achieved by placing a power switch between the power supply and the circuit block. When the block is unnecessary, the switch is open, thereby nullifying any power flow and also eliminating the leakage current. One of the complications associated with power gating is handling the transition from ‘on’ to ‘off’ states. By including the tasks of preserving and restoring the state of the circuit’s registers and preventing the powered-down block from affecting other active components.
3. Dynamic Voltage and Frequency Scaling (DVFS): Dynamic Voltage and Frequency Scaling (DVFS) is a technical procedure that not only allows the system to change its operational voltage. However, the clock frequency is also based on the current workload, instead of running the two at a constant rate or undergoing clock throttling. In cases such as browsing or when the system is in low-performance mode and the load is low, both voltage and frequency can be decreased. In other cases, the two factors can be allowed to increase again if more performance is desired. Therefore, it is an efficient way to manage power and performance changes throughout the system.
4. Logic Optimisation and Multi-Threshold (Multi-Vt) Cells: Logic optimisation employs design methods that increase the number of transistors or switching activity indirectly. Take, for instance, a project alteration that utilises fewer complex logic gates, which can thereby lower capacitance and dynamic power. Additionally, the employment of multi-threshold (Multi-Vt) cells is a crucial technique. A possible implementation in a high-efficiency design is the use of low-threshold voltage (low-Vt) transistors, which, despite being faster, exhibit higher leakage. In places that are not vitally important, designers may prefer to utilise high-threshold voltage (high-Vt) transistors. Although they are slower, they eliminate a significant amount of leakage and reduce static power.
5. Efficient Physical Design and Placement: Interconnecting wires are the primary components that significantly contribute to power consumption. With less capacitance, the smaller wires will have lower dynamic power. Smart physical design begins by placing neighbouring components close together to minimise the wire path. Moreover, the optimisation of the clock tree, which is the part of the circuit that distributes the clock signal, is of utmost importance, as it consumes a significant amount of power. Several methods are available, such as balanced clock tree synthesis and well-planned distribution of clock buffers, that can reduce the power consumption of the clock tree.
6. Asynchronous Design: It replaces the global clock with signals between different logic blocks to handle data flow. A logic block is activated only when it receives a signal indicating the availability of new data, and it sends a signal back when it has completed processing the data. This way, the clock network power overhead is eliminated, and the circuit parts can be idle when they are not processing data. Although asynchronous design may be challenging to understand, data-driven systems find it particularly useful for low-power operation. Numerous VLSI chips are designed with a mix of synchronous and asynchronous blocks to achieve performance and energy optimisation.
7. Efficient Data and Bus Encoding: The switching activity on data buses and internal interconnects is one of the significant factors for dynamic power consumption. The actual data encoding techniques are employed by the designers to address the issue of high signal transitions on these buses. A practical example of this is where, instead of transmitting a data word that contains many changing bits, an encoder can convert the data into a code that has only a few bits changing. The result is a considerable reduction in the voltage levels, and thus, the capacitance is charged and discharged significantly. This phenomenon is associated with long wires that transmit power at a much lower rate.
8. Transistor Sizing and Technology Selection: Transistor sizing is the process of selecting the best size for every transistor to adhere to timing requirements and reduce power consumption at the same time. Moreover, non-critical path transistors can be downscaled to conserve power. However, timing-critical path transistors are allowed to be overscaled to ensure guaranteed performance. In addition, the choice of technology for manufacturing is important, and the best technologies have all the potential for improvements in leakage current and power efficiency. Therefore, the size of a transistor directly affects its speed and also the power consumption.
Final Words
Overall, the transition from energy-consuming to energy-efficient electronics is a concept that helps new development. To demonstrate, whether it is about mobile phones or computing environments, the newly sought-after decrease in energy has finally evolved from an option to an actual choice for sustainable and high-efficiency choices. Endowed with their embedded product design services, many companies have started to ensure optimised power performance, thus helping the world to manufacture electronic gadgets that are smart and sustainable. Not only does this transformation drive innovations, but it also influences design approaches in various fields.
