New Wireless Charging IC from ST Designed to Amp Up Power Transfer

February 26, 2020 by Cabe Atwell

The STWLC68 integrates a high-power receiver and transmitter with a 32-bit Arm Cortex microcontroller core.

Wireless charging is quickly becoming the ideal platform for charging mobile devices. With the onset of 5G communications and demand for increased power and efficiency, manufacturers are looking to new wireless charging ICs that can handle those demands.

To that end, STMicroelectronics has introduced a new wireless charging IC for those manufacturer’s next-gen technologies.


Power Efficiency

The company’s STWLC68 IC enables rapid power transfer and power-sharing via FOD (Foreign Object Detection), which can operate as both a power transmitter and receiver, managing up to 5 W of output power.



The STWLC68. Image (modified) used courtesy of STMicroelectronics

STMicroelectronics states, “The STWLC68 shows excellent efficiency performance thanks to the integrated low-loss synchronous rectifier and the low dropout linear regulator: both elements are dynamically managed by the digital core to minimize the overall power dissipation over a wide range of output load conditions.”

The chip was designed around a 32-bit Arm Cortex-based microcontroller and has a 3.6 V to 20 V programmable output voltage with 25 mV resolution.


Power transfer phases for Baseline Power Profile.

Because the STWLC68 offers a maximum power input of 5 W, the device only supports a Baseline Power Profile as illustrated. Image used courtesy of STMicroelectronics


In addition to an integrated 27 V synchronous rectifier with 98% (typ.) efficiency, the device also features a low dropout linear regulator with output current and input voltage control loops. 


Highlighted Specifications

Additional features of the STWLC68 include: 

  • Six configurable GPIO
  • 8-channels/10-bit A-D converter
  • 400 kHz I2C interface
  • Output over-voltage clamping protection
  • On-chip thermal management and protections (over-voltage/over-current)
  • Enhanced power dissipation capability Chip-Scale Package (CSP)

STMicroelectronics states the chip can be accessed via I2C and its parameters modified and tailored for custom configurations to meet any wireless charging applications. Once the parameters have been set, they can then be saved in the chip’s OTP memory and automatically retrieved on power-up, which lets the STWLC68 act as a stand-alone device.


Block diagram of STWLC68

Block diagram of STWLC68. Image used courtesy of STMicroelectronics

The STWLC68 is designed to support the Qi 1.2.4 inductive protocol and BPP (Base Power Profile), which makes it compatible with all Qi devices on the market.


Availability and Support Tools

STMicroelectronics’ STWLC68 wireless charging IC is available now, along with a pair of evaluation boards, the STEVAL-ISB68RX and STEVAL-ISB68WA.

The STEVAL-ISB68RX and STEVAL-ISB68WA are designed for rapid prototyping for standard 5 W applications and PCBA-sensitive 2.5 W low-power applications, respectively.