As the third controller in the ST-ONE family, the ST-ONEHP has 28V output capability to simplify building chargers and power adapters rated up to 140W. Sharing the ST-ONE architecture, the converter is a non-complementary active-clamp-flyback zero-voltage-switching (ZVS) topology that ensures superior efficiency at high power output and switching frequency. Essential features including secondary regulation and the USB PD communication interface are integrated, saving bill-of-materials costs as well as PCB size and complexity. Built-in synchronous rectification helps maximise efficiency and reinforced galvanic isolation permits a solution that is both compact and safe.
Inside the ST-ONEHP, an Arm Cortex-M0+ microcontroller maintains overall control. The MCU is supplied pre-loaded with certified USB PD firmware, which eases end-product approval to qualify for the USB logo. With 64KByte of flash storage, the MCU provides room for customising the power-conversion firmware.
The ST-ONEHP is well suited to use with ST’s MasterGaN single chip, integrating the Company’s third-generation gallium nitride (GaN) power transistors and optimised gate drivers. The SiP ease the adoption of GaN technology in energy-conscious applications to realise benefits including superior thermal performance and switching efficiency compared to conventional silicon transistors.
Complementing the properties of the ST-ONE converter, MasterGaN helps maximise performance and allows high switching frequencies that permit smaller passive components. By combining the ST-ONEHP controller and a 9x9mm MasterGaN1 half-bridge device, ST has produced the EVLONE140W reference design smaller than a standard 65W laptop charger.
Its volume of 90cm3 equates to a power density of 25W/in3, while the peak efficiency reaches beyond 94%. From an environmental perspective, the charger can use just a quarter of the plastics and is 2% more efficient than average chargers. Using these products in all chargers produced worldwide would save 3.5 million tons of CO2 emissions.
Samples of the ST-ONEHP are already available for selected customers in an SSOP36 leaded package, priced from $3.90 for orders of 1,000 pieces.