Unlocking silent, ultra-thin design for consumer electronics

As AI usage continues to gain traction, system designers must balance the demand for smaller form factor devices with higher performance capabilities that generate significantly more heat.

The increasing performance and ‘always on’ requirements of AI at the edge, in laptops, edge appliances, and even smartphones, are over-taxing conventional cooling solutions. The additional heat generated by processors and AI accelerators has a big impact on system design, limiting how thin or small a device can be—particularly if that system requires a mechanical fan to cope with the heat. It also compromises the reliability of the system, as the fan is often one of the first components to fail.

Insufficient cooling results in systems being throttled, both in design and in operation, to stay within a specific thermal envelope. In addition, localized heating may compromise neighbouring components such as SSDs and DRAM, reducing their performance and reliability. As thermal demands increasingly constrain design, the industry needs alternative cooling technologies that promise more than just heat mitigation.

Critical to system design

The design of space-constrained computing systems like laptops has not evolved much in the past decade. Despite advancements in component miniaturization, particularly in data storage solutions, thermal solutions have remained largely frozen in time. The desire to minimize acoustic noise has forced designers to select fans that are up to 90mm in diameter. These fans consume a large amount of space in a laptop and force the motherboard into the remaining space, creating waste and electrical layout headaches.

The adoption of AI solutions continues to place a greater thermal demand on all personal computing systems, including laptops. The general rule of thumb is that for tasks such as querying and photo editing, which remain on the NPU, or for light-duty video editing, which moves to an integrated GPU, using a large language model (LLM) adds an extra 5-10W in heat load. This increase in power raises even entry-level model laptops to at least 20-25W TDP. When designing a device with a speech-based interface, baseline acoustic levels become even more important to maintain information fidelity. To address these challenges, essentially all laptops need to employ two large blowers in the thermal design. Only in this way can sufficient airflow be achieved at low enough fan speeds to maintain acoustic levels <28dBA.

Another option for tackling the heat problem in processors is liquid cooling. While commonly used in data centers and desktop computers, this approach has not been sufficiently miniaturized in a cost-effective manner to be deployed in laptop computers and smaller devices. Although liquid cooling can reduce the reliance on air blowers, these solutions add significantly to device complexity, risk, and cost, especially for portable systems.

With all the focus on processor cooling, other parts of the system present significant cooling challenges for thermal design engineers. Chassis surface temperatures as well as peripheral components such as SSD and DRAM often receive secondary consideration. System dimensions, such as laptop thickness, are often limited by the distance between the thermal module and chassis surfaces. Placement of peripherals is frequently dictated by placement in airflow streams such that their temperatures can be appropriately maintained.

What system designers need is more freedom to layout components and affect industrial design without needing to base everything around large fans. Blowers take up a tremendous amount of space leading to PCB waste and complexity as well as lost opportunity for product differentiation. Designers need a new cooling solution that addresses the increasing demand placed by AI while still providing more space for additional peripheral devices or a larger battery.

The solution: ionic cooling engine (ICE) technology that enables low-profile, solid state air movement systems. In addition to providing a completely silent cooling solution, ICE technology dramatically opens design options for smaller, high-performance AI-enabled devices.

ICE technology leverages electrohydrodynamic (EHD) airflow to deliver intelligent air movement that cools devices without moving parts, noise, or vibration. ICE devices are much smaller than traditional fans and have a thin, design-friendly rectangular form factor. Breaking a system down into discrete zones (power, computing, and cooling) allows for greater design flexibility. For example, motherboards, which focus on distributing power and enabling communication between components, need no longer be encroached upon by bulky fans. In addition, ICE technology can be scaled to dimensions much smaller than can be achieved by a fan. This presents an opportunity to use multiple small, low-profile blowers in just the right place to cool peripheral components and maintain comfortable surface temperatures. Overall, ICE technology can reduce the size and complexity of systems while enabling the higher performance needed for next generation designs.

Cooling in a zoned architecture

Thermal management solutions that leverage ICE technology provide more than just a fan replacement. By themselves, ICE solutions enable airflow with complete silence. Independent testing shows that ICE-based subsystems operate at <15dBA, which is well below any available conventional fan. But ICE-based devices are also significantly smaller than fans which easily allows for a zoned architecture approach as shown below. The zoned architecture completely compartmentalizes different functions leading to efficiency and cost savings.

Using the zoned approach, the motherboard no longer needs large cutouts for fans. This simplifies PCB depanelization and milling and reduces waste. Traces on the pcb no longer need to travel through narrow pinch points created by fan cutouts. Direct routing of traces from IO boards to the motherboard can eliminate the need for costly signal repeaters. In some cases, the number of layers in the PCB can be reduced due to the increased space for routing.

Ventiva’s ICE solutions can free up to 80% more board space currently taken by traditional fans, allowing designers to increase the size of a battery or add functionality without changing the overall footprint dimensions of their machine. This allows designers to offer more brand differentiation and give consumers several expansion options.

All the cost and area savings mentioned are enabled by using a zoned architecture. These benefits are in addition to the silent, reliable cooling made possible by ICE technology.

Redefining the way devices are designed

The rise of AI is increasing the thermal burden on consumer systems, from laptops to smartphones. This extra power dissipation is a major headache for system designers who are looking to make high performance devices that are smaller and thinner. Existing cooling technologies such as fans have reached their limit, while other approaches such as liquid cooling can be complex and expensive. Solid state ionic cooling solutions offer a completely silent and reliable fan replacement in existing designs, but this is just the starting point.

By taking advantage of the zoned architecture enabled by ionic cooling devices, designers also reap the rewards of reduced cost and increased area in their system—space that can be used to extend battery life, increase storage capacity, and more.

Thermal management subsystems powered by ionic cooling technology are expanding design possibilities for developers, offering a low-profile, compact form factor solution with flexible placement options. These devices can unobtrusively break out of the cooling zone to direct airflow to troublesome hotpots. Being able to place an air blower right where cooling is needed can further help developers integrate the latest AI technologies in their products to enhance the user experience, while still reducing the size of the system.

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Dr. Brian Cumpston is director of application engineering at Ventiva, a supplier of thermal management products based in Freemont CA. Cumpston leads the integration of advanced thermal management technologies into consumer electronics and computing platforms.