Silanna Semiconductor Introduces Integrated ACF Controller for Power Supplies Applications

Silanna Semiconductor Introduces Integrated ACF Controller for Power Supplies Applications

Silanna Semiconductor, The Power Density Leader, has expanded its CO2 Smart Power Family of AC/DC and DC/DC converter technologies with the launch of an active clamp flyback (ACF) controller that integrates adaptive digital PWM control with ultra-high-voltage (UHV) components comprising a 700 V primary GaN FET, X capacitor (X-Cap) discharge circuit, active clamp driver and start-up regulator.

Silanna’s CO2 Smart Power technologies help engineers by simplifying design and improving performance while addressing environmental sustainability goals through more efficient energy use. Well-suited for high-efficiency and high-power-density power supplies, USB-PD/QC AC/DC power adapters, and battery charging applications, the new SZ1200 integrated ACF controller combines the ease of design of a simple flyback controller with all the benefits of ACF. These include recycling the leakage inductance energy of the flyback transformer and limiting primary FET drain voltage spikes during turn-off events.

Delivering above 93% efficiency at low line, the SZ1200 offers consistent efficiency across the universal input voltage range (90 - 265 Vac) and various loading conditions of up to 150 W single-port and multi-port USB-PD applications. Silanna’s OptiMode digital control architecture adjusts operation mode on a cycle-by-cycle basis to maintain high efficiency, low EMI, fast dynamic load regulation, and other key power supply parameters as line voltage and load vary. Very low no-load power consumption for the most stringent USB-PD applications further minimizes energy use during system stand-by.

“Our goal is to make it as easy as possible for power design engineers to develop ultra-efficiency, high-density power conversion designs in the shortest time possible,” says Ahsan Zaman, Silanna Semiconductor’s, Director of Product Marketing. “The addition of the SZ1200 to our family of ACF technologies supports this goal by offering high-speed switching, unprecedented levels of integration, and functionality that ensures optimum efficiency across wide input and loading conditions while minimizing EMI.”

By allowing designers to program switching frequency to up to 250 kHz, the new controller supports high power densities while advanced digital active clamp operation ensures best-in-class efficiency. Switching frequency is confined within a tight frequency band to simplify EMI filtering. Further efficiency and EMI performance benefits are realized through adaptive digital control of the active clamp operation, which enables near ZVS turn-on of the primary FET and clamps the drain voltage during the turn-off.

SZ1200 also incorporates continuous conduction mode (CCM) operation, which allows delivering up to 225% rated output power for a limited duration without sacrificing the power density. This feature is targeted for applications requiring peak power, such as laptop and notebook power adapters.

The SZ1200 integrates advanced features for enhanced performance and efficiency. It includes a high-frequency 'COSmart Power' ACF controller with configurable operation up to 250 kHz, a 700 V GaN primary FET, and essential components like a UHV X-cap discharge circuit. Efficiency exceeds 93% at low line conditions and remains consistent across universal input voltage ranges. With CCM for increased peak power delivery, QR valley mode switching for low EMI and comprehensive protection features, it ensures precise operation and fault protection. Housed in a compact 37-pin 8 mm X 7 mm QFN Package, engineering samples are targeted for April 2024, with full production by the end of Q2, 2024.