STMicroelectronics' STWLC03 is a high-efficiency wireless power receiver IC that supports both Qi and PMA protocols. Along with the wireless power receiver, it integrates a programmable buck converter and an embedded microcontroller, which allows for a very wide range of customization and supporting different standards.
Qi and PMA are fundamentally similar, but they use different protocols. Both use magnetic induction and both operate in the hundreds of kilohertz, so the receiving coils and hardware can easily be designed to cover frequency ranges for both standards. However, despite these similarities, the messaging protocols are different, so if you use mismatched transmitters and receivers power will not be delivered to the receiver because they can't communicate.
Dual mode receivers solve this problem. At one point many high profile businesses implemented PMA charging pads, but at the time most devices had Qi receivers. This led to a lot of user confusion and frustration. But this becomes a non-issue with the STWLC03. The IC works by measuring the operating frequency received from the charging pad and FSK signaling to determine if the transmitter is using Qi or PMA. If it's PMA, it determines which type of PMA is being used. This allows wireless power receivers to be placed on charging pads of either type and receive power. It also provides flexibility in that a device can be designed for either protocol using the same IC because it has an option to override detection and always operate in a single mode, whether that's Qi or PMA. And an external supply detection cuts off power transfer if the device is plugged in while on the charging pad.
Many early wireless chargers were also slow, but the STWLC03 is capable of 12 W output to the device, similar to or better than many USB adapters. This would be equivalent to a 2.4 amp charger. The device can be used in power supply mode and set to output a configurable voltage, or in CCCV mode for battery charging with a configurable current.
Beyond the ability to support both Qi and PMA, the STWLC03 integrates a high-efficiency synchronous rectifier allowing buck converter efficiency to reach 92 percent, 2 KB of nonvolatile memory to retain custom settings, and four GPIOs.
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