Reference design provides a compact AC-DC adapter using gallium nitride switching and synchronous rectification for efficient power conversion.
Vistar Technovation has developed a 65 W GaN adapter reference design for applications such as laptop chargers and LCD monitor adapters. The design accepts an AC input ranging from 90 V to 300 V and provides a regulated 19 V DC output. It is designed without a heat sink and incorporates gallium nitride switching technology to achieve a compact implementation.
The reference design uses an integrated high-voltage depletion-mode gallium nitride MOSFET and a secondary-side regulation topology. It operates from a 50 Hz input with a ±10 per cent frequency tolerance and has a maximum no-load power consumption of 75 mW. The output can deliver up to 3.4 A, with the page specifying a maximum output power of 75 W.
Synchronous rectification is implemented on the output side using a synchronous rectifier and MOSFET. This approach is intended to improve conversion efficiency and thermal performance. The design achieves an average efficiency of 90 to 92 per cent and has a maximum output ripple of 100 mV.
The adapter incorporates protection features including overtemperature protection, overcurrent protection and short-circuit protection. It also supports constant-power and constant-current modes. These features are integrated into the design to support reliable operation under different load and fault conditions.
The design is described as a compact and reliable solution intended to withstand Indian field conditions. Its combination of gallium nitride switching, synchronous rectification and a heat-sink-free implementation makes it suitable for compact power-adapter applications. Engineers can use the reference design to evaluate the power-conversion approach and develop adapter designs for applications such as laptops and LCD monitors.
For more information, click here.
