Date: 04/09/2012

Wireless charging tech: what's latest in this hot new feature

Mobile device users prefer not to plug-in the charger pin everyday to charge their mobile devices such as phone, tablet, or even a notebook computer. They would just like to keep it over wireless charger unit for charging. There are reports that new Nokia Lumia 920 to feature wireless charging. It can be easily estimated the wireless charging going to be a hot feature in new smart phones.

In-Stat had surveyed more than a year ago to find approximately 44% of respondents saying current mobile charging solutions are an annoyance. Additionally, up to 40% are willing to pay $50 more for a wireless charging solution. As a result of this and other factors, In-Stat had projected the market for wireless charging systems will reach $4.3 billion in total market revenue by 2014.

Rajiv Kumar, Analyst from Frost and Sullivan had said "with wireless charging, consumers will no longer have to depend on wired chargers to juice-up their mobile phones, tablets and cameras. The technology involves a metal plate, which will charge the device wirelessly, and will be deployed in public places such as airports, cafes, and restaurants".

Well, that is briefly about the market forecast. The technologies, semiconductor ICs and other passive components recently announced includes:
Semiconductor company Integrated Device Technology (IDT) has announced that Intel has selected IDT to develop an integrated transmitter and receiver chipset for Intel’s wireless charging technology based on resonance technology. IDT aims to deliver validated reference designs that are targeted for deployment in Ultrabooks, all-in-one (AiO) PCs, smartphones, and standalone chargers. IDT said it is targeting samples of a resonance receiver IC by the end of the year 2012, and the transmitter IC is expected to sample in the first half of 2013 IDT says its wireless charger IC IDTP9030 reduces application footprint by 80 percent and solution BOM by 50 percent compared to other solutions. Charging stations that take advantage of the IDTP9030 may be deployed virtually anywhere, including homes, offices, libraries, stores, public waiting areas, automobiles, airports, and airplane seats.

Another leading semiconductor company Texas Instruments Incorporated has introduced its wireless power receiver IC for designing wireless charging of portable consumer devices, such as smart phones, gaming systems, digital cameras, and medical and industrial equipment. The bq51013 receiver integrated circuit (IC) combines voltage conditioning and full wireless power control in a small 1.9-mm x 3-mm WCSP package. The new circuit supports up to 5 W of output power, provides up to 93-percent efficient AC/DC power conversion and is the only IC required between the receiver coil and system.

Efficient Power Conversion Corporation (EPC) has announced a high efficiency wireless power demonstration system utilizing the high frequency switching capability of gallium nitride transistors. EPC states in its release "Highly resonant wireless power transfer was invented by the founders of WiTricity, and WiTricity licenses its intellectual property to companies seeking to build products based on this exciting new technology. Capable of transferring power over distance, WiTricity technology enables a wide range of consumer, medical, industrial and automotive applications. Products using highly resonant wireless power transfer can meet stringent regulatory guidelines, and is safe for people and animals."

EPC explains many wireless charging products now in the market use traditional magnetic induction coils with operating frequencies between 100-300 kHz, and Class E, F and S amplifier converter topologies Recently, organizations such as the Consumer Electronics Association and A4WP (Alliance for Wireless Power) have called for a higher frequency standard (6.78 MHz) for wireless charging systems. At higher frequencies, traditional silicon-based power transistors (MOSFETs) approach the limit of their switching capability. EPC’s eGaN FETs offer higher efficiency compared to MOSFETs at these higher frequencies.

Vishay Intertechnology has made available IWAS-4832FF-50 wireless charging receiving coil for wireless power base stations and receivers. The IWAS-4832FF-50 is powdered-iron-based, WPC-compliant (Wireless Power Consortium) wireless charging receiving coil optimized for use with or without an alignment magnet.

Passive component expert TDK Corporation has developed wireless power transfer coil unit designed for Smartphones and other mobile devices. The receiving coil designed for integration in Smartphones and similar is 0.57 mm thick.

The coil's design minimizes the tendency towards rising resistance and achieves a power transfer efficiency that allows clearing the requirements of the WPC "Qi" standard. The low height of the unit is a key aspect for use in Smartphones. At this point, output current is on the order of 0.5 to 0.6 Amperes, but an even thinner 0.50 mm type with equal or better output current is already in development, with a view towards starting mass production in 2013, discloses TDK.

Fujitsu Laboratories Limited has developed wireless recharging technology that can simultaneously recharge various types of portable electronic devices.

Fujitsu claims this technology not only promises more compact and more efficient power transmitters and receivers, it also offers the ability to design charging systems in 1/150th the time currently required. In addition to dramatically shortening development times, this technology paves the way to integrating compact wireless charging functions into mobile phones and enabling multiple portable devices to be charged simultaneously without any restrictions on their position with respect to the charger.

In the academic circle, researchers from North Carolina State University have developed a new way to fine-tune wireless power transfer (WPT) receivers, making the systems more efficient and functional. WPT systems hold promise for charging electric vehicles, electronic devices and other technologies.
Author: Srinivasa Reddy N