Wireless charging technology is technically challenging, requiring advanced mixed-signal architecture, according to IDT's CEO. "Our competitors are trying to catch up but are still failing," he said.
What makes it so difficult?
The big problem is that, even when using the inductive coupling principle, different appliances have different range and power requirements. The solution is a variable frequency solution, explained IDT's Naghavi. He explained that devices based on WPC or PMA specs use variable frequencies ranging between 100kHz to 200kHz or 300kHz, requiring different load and power.
IDT's engineering team, led by Naghavi, came up with architecture -- integrated with a microcontroller -- that can modify itself through firmware.
Integrated into IDT's dual-mode receiver chip are a high-efficiency synchronous full bridge rectifier, high-efficiency synchronous buck converter, and control circuits to wirelessly receive an AC power signal from a compatible transmitter and convert it into a regulated 5V output voltage for powering and charging portal electronics, according to the company. The device delivers 5W in WPC and PMA modes in accordance with those standards. When paired with IDT wireless power transmitters, systems can make use of the proprietary power control loop embedded in the communication protocol to achieve a 50 percent increase in output power to 7.5W, IDT claimed.
Will there be a solution in the offing that can support not just magnetic induction technology such as WPC and PMA, but also the magnetic resonance technology-based A4WP spec? Although magnetic resonance uses a very high frequency -- such as 6.78MHz -- compared to magnetic induction, the principle of supporting variable frequency remains, requiring a rectifier based on frequency, Naghavi explained.
IDT has been working on wireless charging technology for two and a half years, said Naghavi. Seeking to develop a single architecture that can be modified through firmware, Naghavi went to a potential customer and boldly vowed: "We will make our solution dual-mode and we will do it on a single chip." At the time, IDT's competitors, such as Texas Instruments, were struggling to find a stable solution, using eight chips. A year later, when Naghavi showed up with the promised sample, "the customer told me two words -- "wow" and "congratulations," according to Naghavi. The customer told him: "A year ago, I thought you were crazy."
No one knows yet how quickly a wireless charging infrastructure will build up. Cellular operators are serious about wireless charging, because they want to send specific advertisements -- such as "muffins are on sale today" -- to mobile phones placed at charging stations at coffee shops, fast food joints or airports, explained McCreary.
Less clear is the wireless charging market for the home, he noted. "There is a cool factor" to wireless charging, noted McCreary, but it might be trumped by practicality. After all, most homes have plenty of handy power plugs.
Samsung offers for its smartphone a wireless charging cover as an accessory.