Non-contact Charging System Simultaneously Charges Multiple Mobile Devices

Nov 13, 2008
Hiroki Yomogita, Nikkei Electronics
Non-contact charging modules (the one on the right is for transmitting electric power and the one the left is for receiving it)
Non-contact charging modules (the one on the right is for transmitting electric power and the one the left is for receiving it)
[Click to enlarge image]
The sheet that can simultaneously charge multiple devices
The sheet that can simultaneously charge multiple devices
[Click to enlarge image]

Mojo Mobility Inc, a Silicon Valley-based venture firm, developed a technology to simultaneously charge multiple mobile devices using a piece of sheet and started seeking collaboration with device manufacturers.

The non-contact charging system employs an electromagnetic induction method and is characterized by its thin coil areas used for transmitting and receiving electric power. It can be installed inside thin devices such as mobile phones and realize a charger as thin as a mouse pad. The system is composed of two coils, one for transmitting and the other for receiving electric power.

The company has already prototyped a sheet-type charger equipped with multiple transmitting coils. On this sheet, up to four mobile phones can be charged at the same time, according to Mojo Mobility.

For use in mobile phones and headsets

Mojo Mobility calls this technology "NFP (Near Field Power)." It explains the prototype can supply electricity of 2.5W to 4W and charge mobile phones, headsets and mobile music players. The efficiency of electric power transmission is higher than 70%, including the peripheral circuit, according to the company.

"Today, each family owns a number of mobile devices, and rooms are a mess of charger cables," said Afshin Partovi, CEO of Mojo Mobility. "Using our technology, charger cables of multiple devices can be replaced with one single sheet."

The company says it has applied for more than 15 patents on related technologies.

Mojo Mobility intends to supply the non-contact charging module to device manufacturers and suggest material manufacturers that they embed the receiving coil in their packages of Li-ion secondary batteries.

Furthermore, the company envisions making a one-chip control circuit and incorporating the non-contact charging control circuit in power management ICs for devices. For this purpose, it has been considering the possibility of collaborating with semiconductor manufacturers that produce power supply control ICs.