A New Member of the Fan Club

Smartphones and tablets are simultaneously getting more powerful and thinner with every new generation of device that is released. They are also being asked to run more taxing applications all the time, especially with the proliferation of on-device artificial intelligence (AI). But as any good engineer knows, thinner form factors and powerful processing units do not really go together. In fact, this situation can be an absolute nightmare from a thermal management perspective.

Modern portable devices have been shrunk down to proportions that make it virtually impossible to use traditional fans to remove hot air from the case — even if consumers would accept the buzzing and vibration that they create. So virtually all portables now use passive cooling solutions that channel heat away from chips and to the device’s case. This can only do so much, however, especially when one’s hand, which generates plenty of heat of its own, is cradling that case.

When chip temperatures climb too high, there is little that can be done aside from intentionally throttling down their speed. Needless to say this negatively impacts performance and user experience, so it is far from ideal (yet a big step up from melted chips that brick devices). This trade-off may no longer be necessary, even in the thinnest of devices, due to the release of a tiny fan-on-a-chip that can draw air out of even the thinnest of device cases.

Manufactured by xMEMS, the XMC-2400 cooling system operates on completely different principles than traditional fans. There are no spinning blades to take up space and make noise. Instead, the device, which is packed into a tiny, 0.25 centimeter-thick chip, works something like a piezoelectric microspeaker. This may seem odd at first blush, but while their goals are very different, both speakers and air-cooling systems move air around.

Internally, the chip contains materials that change their shape when an electric current is applied to them. In this way, they can fill a cavity with air via suction before changing shape to expel it through a vent. As might be expected, such a tiny chip can only move a tiny amount of air. But the material inside the chip can shift its shape very rapidly — hundreds of thousands of times per second. By pushing small amounts of air in such rapid succession, meaningful levels of cooling can be achieved with the XMC-2400.

The solid-state cooling chips are produced on silicon wafers using standard manufacturing techniques, so they can be manufactured in large quantities to meet the needs of device manufacturers. The chips are also quite versatile due to their diminutive size. They can either be placed directly on top of another chip, like an SoC or a GPU, to draw away heat, or they can be positioned at the edge of the case to pull heat out through vents.

Integrating technologies such as the XMC-2400 into future mobile devices has the potential to make AI applications more performant and secure while helping to enhance user privacy. Not bad for a little fan-on-a-chip, huh?