Qi 1.2 Compliant 15W Wireless Charger Solution

February 14, 2018 by Paul Shepard

STMicroelectronics makes it easy for developers to evaluate and quickly get their design to market using this comprehensive evaluation kit for a 15W, Qi 1.2 compliant, end-to-end wireless charging solution based on the STWBC-EP / STWLC33 chipset.

Optimized for Extended Power Profile (EPP) Wireless Power Consortium (WPC) Qi 1.2 certified applications up to 15W, the STWBC-EP digital controller for wireless battery charger transmitters provides maximum flexibility as it enables half- or full-bridge topologies as well as single- and multiple-coil designs and Flash memory for code storage.

The STWLC33 multi-mode wireless power receiver with transmitter function ensures the highest efficiency with the lowest part count and system cost. Compatible with Qi 1.2 or AirFuel inductive communication protocols, it can be switched to transmitter mode to provide power to another receiver.

Designed for devices requiring high power levels such as smartphones or tablets, the following development tools are available:

The STEVAL-ISB044V1 evaluation kit has been designed for devices, such as smartphones or tablets, requiring high power levels. The embedded STWBC-EP digital controller transmitter is based on a cost-effective half-bridge topology providing external interfaces via UART and I²C.

The kit also includes STWBC-EP firmware, a graphical interface for debug, schematics, layout files and bill of materials.

There are specific tools for the STEVAL-ISB044V1 available on which give runtime information, such as the power delivered, the regulation error or the protocol status as well as parameter tuning.

Key features of the STEVAL-ISB044V1 evaluation kit

  • STWBC-EP digital controller
  • 15W output power
  • Qi MP-A10 reference design
  • WPC Qi1.2.3 standard compliant
  • Robust demodulation algorithm, with triple path (V, I, f)
  • Foreign object detection (FOD)
  • Accurate power control
  • Active presence detection
  • UART protocol to control and monitor the system
  • Complete reference design (evaluation board, IC, firmware and tools)
  • 2-layer PCB for easy design
  • Flash memory-based
  • RoHS compliant

Also included is the STEVAL-ISB042V1, a 15-watt Qi and 5-watt Airfuel inductive (former PMA) wireless power receiver evaluation board based on the STWLC33 wireless power receiver solution for the WPC/Airfuel mobile device with dual mode coil.

The board enables evaluation of the STWLC33 capabilities as a Qi/Airfuel inductive receiver as well as its ability to power another Qi receiver. The solution is certified in accordance with the extended power profile Qi v1.2 and Airfuel SR1 standard.

The STWLC33 IC is powered by a dual mode Rx coil attached to a 1.5mm thick plastic fixture.

The STWLC firmware offers users the flexibility to modify parameters and settings to ensure proper integration of the STWLC33 device with the final application.

The layout is based on a cost-effective 4-layer PCB. Key features include:

  • STWLC33 evaluation board with Würth Elektronik dual mode coil (760308102207)
  • Qi 1.2 compliant, supporting extended power profile: up to 15W/10V maximum output power
  • Backward compatible with Qi baseline power profile: up to 5W/5V maximum output power
  • PMA-SR1 (AirFuel inductive) compliant: 5W/5.6V maximum output power
  • Transmitter function based on Qi protocol to charge wearable devices using the same Rx coil (up to 3W power)
  • Total system efficiency up to 80%
  • Configurable GPIOs for status indication
  • I²C interface for communication with the host system
  • Foreign object detection (FOD)
  • Complete kit (IC, firmware)
  • RoHS compliant