SAN FRANCISCO — Hoping to further interest in wireless charging, Broadcom has introduced a multi-standard smartphone charging chip. The BCM59350 chip puts the Association for Wireless Power's (A4WP) resonant standard on the forefront while enabling two other approaches as well.
“Consumers don’t want to be bothered by standards, or standards wars. It’s a matter of convenience, but I see [multi-standard] as a prerequisite for growing the market,” Broadcom Mobile Platform Marketing Director Reinier van der Lee told EE Times. “I think resonant technology will be the technology of the future.”
Broadcom’s chip has an embedded frequency detector to enable automatic selection among specifications from three leading standards organizations: A4WP, the Power Matters Alliance (PMA) -- which uses loosely coupled coils for easier charging -- and Wireless Power Consortium’s (WPC) close-coupled inductive charging. WPC’s Qi inductive standard operates at 100 to 200 kHz, while PMA’s resonant technology runs at 200 to 300 kHz and A4WP’s Rezence technology at 6.78 MHz, a spectrum reserved for industrial, medical, and scientific use.
The chip is currently sampling and will be in mass production by the second quarter of this year. MediaTek debuted a similar product at CES this year. Ryan Sanderson, an IHS market analyst, says other multimode devices from Texas Instruments and IDT support only Qi and PMA.
The Broadcom chip can be added into the hardware of a handset or as an accessory in the form of a wireless charging sleeve, but it does not allow for resonant and inductive devices to charge on the same charging pad. Broadcom has developed a resonance charging pad, but van der Lee says the pad will not be multi-standard compatible. Resonance charging requires Bluetooth to communicate between receiver and transmitter, while inductive charging relies on load modulation.
One of the sticking points among wireless charging skeptics has been time to charge, with many saying wireless chargers take too long. Van der Lee added that the new chip, regardless of inductive or resonant capabilities, will boost charging power beyond what is currently capable with a micro USB and wall charger, which are limited to 1.5 amps and 5V. Broadcom’s chip can support up to 7.5W, but the company may experience competition from wired connectivity vendors.
“There is, however, a big drive in the wired charging world to provide fast charging, and solutions are likely to arrive on the market as early as 4Q this year,” says Sanderson, an associate research director of power supply and storage components at IHS. “They are likely to provide between 9W and 18W to compatible devices which will charge them much faster.
The high-powered chargers may reduce of the number of charge cycles in battery's lifetime. "A good battery management solution is required,” Sanderson says.
While Broadcom hasn’t tackled rapid wireless charging in this chip, van der Lee pointed to the chip’s “boost mode,” which extends the normal operating range from 5V-20V to 2.5V for charging when the phone is placed just outside the charging area of the transmitter coil.
Broadcom’s chip also has a variety of switches that allow Bluetooth in an otherwise dead phone to gather charge and connect to a resonant charging pad. Once placed on a pad, beacon signals will detect the presence of Bluetooth and charge the chip enough to connect.
“These solutions offer OEMs the confidence to implement wireless charging today,” Sanderson notes. “This shows Broadcom’s commitment to driving A4WP Rezence technology [while] remaining compatible with other standards.”
— Jessica Lipsky, Associate Editor, EE Times