STMicro Wireless 50W Qi Charging ICNovember 12, 2020 by Gary Elinoff
The new chip enables wireless charging to take place almost as quickly as charging via cable
Aimed at laptops, smartphones, and tablets, ST maintains that its new STWLC88 is the world’s fastest wireless charging IC, beating out last generation devices by a factor of two.
STWLC88. Image courtesy of ST
The STWLC88 is a highly integrated wireless power receiving IC aimed at applications of up to 50 watts. The device supports the latest Qi specifications for fastest charging, including the Extended Power Profile (EPP) and proprietary STSuperCharge (STSC) protocols
“ST’s latest STWLC88 wireless-charging IC provides the best solution for wireless-charging applications with industry-leading efficiency, highest power delivery, and maximum safety,” said Francesco Italia, General Manager, Analog Custom Products Division, STMicroelectronics. “With the launch of the world’s fastest charger, ST has expanded the portfolio to cover a wide range of power levels to meet the increasing demand for higher-power chargers in the age of 5G communications.”
The STWLC88 can serve to reduce the external part count to achieve a lower BoM. The unit can also be partnered with the STWBC2 digital controller to achieve power goals while staying compliant with WPC Qi 1.2.4 EPP.
The Importance of Efficiency
To ensure efficiency, the power charger chip employs an ultra-low impedance, high-voltage synchronous rectifier. While the actual costs of power involved in running wearable devices is minimal at best, efficiency, especially on the receiving end is nonetheless important, because inefficiency means heat buildup, which is a notorious source of trouble for electronic devices.
The STWLC88 is integrated with a 27-volt synchronous rectifier with greater than 98% efficiency, and a low drop-out linear regulator (LDO) with output current and input voltage control loops. The LDO regulator is programmable, with an output voltage of up to 20 volts in steps of 25 mV.
The STWLC88 employs advanced algorithms residing on dedicated hardware to enable ASK and FSK communication during high power charging.
For safety, the device features a Foreign Object Detection (FOD) along with a current-sensing system. These help ensure that its task of delivering high charging power is performed in a manner that is both safe and well-controlled.
The embedded few time programmable (FTP) memory can be programmed via an I2C master/slave interface for customization and to enable support for proprietary charging protocols.
The STWLC88 can also serve as a method of charging other devices. In its transmit (Tx) mode, it can itself be a source of up to 12 watts of charging power, the actual output being a factor of the coil employed.
- The device supports the Qi EPP 1.2.4 inductive wireless standard communication protocol compliant
- The unit incorporates a 64 MHz, 32-bit ARM Cortex MCU core
- There is an 8-channel, 10-bit A/D converter
- There are eight configurable general purpose I/O’s (GPIO)
- External flash for design in is supported
- When in TX mode, the STWLC88 features Q-factor measurement for Object Detection
- Rectifier input frequency ranges from 50 to 300 kHz
- There is an ASK V/I modulator
- Protection against overcurrent, over-voltage and over-heat are incorporated.
- Power banks
The STWLC88 is available in a space-saving, 110 bump flip-chip package measuring 4.07 x 4.49 mm.
Getting to Market Faster
ST offers the STEVAL-ISB88RX evaluation board, which is aimed at helping engineers to more quickly prototype solutions employing the STWLC88. The unit includes the STWLC88 itself as well as a sophisticated GUI system.