Laptop chargers can be smaller with 100 MHz power-conversion switching

December 30, 2013 // By Paul Buckley and Graham Prophet
FINsix, a power conversion startup based in Boston and Silicon Valley, has developed laptop power adapters and LED drivers that claim to be 75% smaller than their conventional counterparts.

FINsix’s first product, which the company will unveil at the forthcoming Consumer Electronics Show in Las Vegas, replaces a conventional charger - the in-line moduel inthe power lead - with a device a little bigger than an ordinary (US-style) plug. The 65-W power adapter - which delivers more power than many laptops use - can charge a futher accessory of up to 10W at the same time as it is charging the main device. The product will be available by the middle of 2014.

The power adapter is the first commercial application of a novel circuit design developed by David Perreault, a professor of electrical engineering and computer science at MIT.

FINsix outlines a familiar story of increased efficiency in power conversion, citing higher switching frequency allowing the use of smaller inductors and capacitors, with reduced storage of energy on every cycle of the conversion. The key differentiator is that FINsix says it can use switching frequencies of up to 100 MHz.

Using improved semiconductor switches and circuit configurations in conventional topologies has reduced losses in the switches, but (in established topologies) attempting to move beyond single-figure-MHz switching rates means that those factors become significant again, impacting efficiency

FINsix says that its use of switching speeds as high as 100 MHz combined with "resonance and wave shaping with new power conversion architectures" enables a high conversion efficiency in a very small outline.

Details of the company's circuit techniques are not disclosed at present, beyond saying that it has "a way to recycle much of the energy that’s normally lost inside a power adapter". It is not clear if the technology applies open-market or custom power switches, but as the management team includes mixed-signal IC design specialists, it appear that FINsix is designing its own controller ASICs.

FINsix’s power adapter is an after-market charger that can work with a variety of laptops and other devices. The company is also working with