Ally Winning, European Editor, PSD
Wireless charging is currently the latest “must have” technology for phone users. According to manufacturers and third party suppliers, it will not be long before almost any surface is convertible to a charging station for phones and other mobile devices. The convenience of having a charger almost anywhere is complimented by a longer device lifetime as the charging port is one of the main points of failure for mobile devices. But, far from being a quirky technology to convince consumers to part with their money, wireless charging technology also has some more serious real world uses.
For instance, in the medical field, researchers at Rice University and the Texas Heart Institute have developed a wireless charging device that is, by definition, a mission critical application. The two groups worked together to create a wireless pacemaker that can be directly implanted into the patients heart. Normally the pacemaker element that is used to dictate the heart rhythm is implanted away from the heart to allow surgeons to easily access the device through minor surgery to replace its batteries. The signals from the pacemaker are then connected to the heart through wires or leads.
The new device created by Rice and THI uses an external battery pack to wirelessy charge a pacemaker implanted directly into the patient’s heart. The device only has a range of several centimetres, which is enough to charge the pacemaker without having to perform surgery. Removing the requirement for leads to the patient’s heart also has health benefits by reducing complications from bleeding and infection. Leadless pacemakers have been attempted before, according to Aydin Babakani of Rice University who led the work, but the form factor of those designs limited their usage.
According to Futurity, the main IC of the system is only 4mm wide and incorporates the antenna, AC/DC convertor, power management technology and the timing device. The chip is situated beside a capacitor and a switch on a dime-sized PCB. The pacemaker is powered and controlled by an 8 – 10 GHz signal from the battery box.
The timing signal can be easily adjusted by increasing or decreasing the transferred power to the pacemaker. To gain a higher heart rate, the power delivered to the pacemaker is raised, charging the capacitor to its threshold voltage more quickly and therefore delivering more timing signals to the heart. To slow the heart beat, the power is lowered. The pacemaker has been tested in a pig and was capable of varying the animal’s heart rate from 100 to 172 beats per minute. Researchers at Rice will continue to develop the design in partnership with UC San Diego.