Ultra-compact custom power management solution for solar energy harvesting watch

e-peas has announced the completion of a significant project for Swiss manufacturer of luxury watches Cartier. Cartier’s new addition to its Tank watch collection is helping long-term energy autonomy, so wearers do not have to trouble themselves with battery replacement and disposal. On average, these watches will run for 16 years - using solar power to keep constantly replenishing their battery reserves. Light that is incident on specific areas of the watch dial surface is absorbed by a high-efficiency photovoltaic element. The e-peas PMIC then transfers the photovoltaic-generated electricity to the battery, which can be utilised to drive the watch mechanism.

Key performance parameters where the company’s PMICs differentiated themselves from others was the capacity to start and efficiently harvest energy at low light levels so that poor indoor light could be sufficient to power the watch. Proper management of the tiny sensitive battery was also crucial to maximise its lifetime. The standby current of the PMIC was required to be minimal, too, so that little power was drawn from the battery when the watch is not being worn and is stored in a dark place. The ultra-compact PMIC specially developed for the Tank watch measures only 2mm x 2mm, making it smaller than any other energy harvesting solution available. The architecture only employs a few tiny external components allowing the complete solution to fit into the very constrained space available in the watch.

As Arnaud Carrez, senior vice president, chief marketing officer at Cartier, comments: “For the very first time, we are introducing an original version of the Tank Watch with a photovoltaic movement, which is utterly pioneering. It took us four years to develop this innovative movement with the help of Richemont Innovation and Manufacture Horlogère de Val Fleurier. Adding advanced energy harvesting capabilities to our Tank watch collection allows us to provide our clients with a watch whose design and quality meet Cartier’s standards while further reducing the Maison’s environmental footprint over its entire life cycle.”

“The number of design wins that we have gained for our energy harvesting PMICs continues to grow, and with this latest project, we are now taking things to a whole new level,” states Geoffroy Gosset, e-peas’ CEO. “Our work with Cartier shows that we have both the technology, innovation and quality to provide industry-leading energy harvesting solutions to the best-known global brands so that they can gain a real competitive edge.”