Silanna Semiconductor 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 primary 700V GaN FET, X capacitor discharge circuit (X-Cap), active clamp driver, and startup regulator.
Silanna's Smart Power CO2 technologies help engineers by simplifying design and improving performance, while addressing environmental sustainability goals through more efficient use of energy. Well suited for high-efficiency, high-power-density power supplies, USB-PD/QC AC/DC power adapters, and battery charging applications, the new SZ1200 integrated ACF controller combines the design ease of a simple flyback controller with all ACF benefits. This includes recycling flyback transformer leakage inductance energy and limiting primary FET drain voltage spikes during turn-off events.
Providing over 93% low line efficiency, the SZ1200 offers consistent efficiency across the entire universal input voltage range (90 – 265 Vac) and various load conditions up to 150 W in single-port and multi-port USB-PD applications . Silanna's OptiMode digital control architecture adjusts the operating mode on a cycle-by-cycle basis to maintain high efficiency, low EMI, fast dynamic load regulation and other important power supply parameters as line voltage and load vary. Very low no-load power consumption for the most demanding USB-PD applications further minimizes power usage during system standby mode.
By allowing designers to program the switching frequency up to 250 kHz, the new controller supports high power densities, while advanced digital active clamp operation ensures best-in-class efficiency. The switching frequency is confined within a narrow frequency band to simplify EMI filtering. Further efficiency and EMI performance benefits are achieved through adaptive digital control of active clamp operation, which enables near-ZVS activation of the primary FET and traps the drain voltage during turn-off.
The SZ1200 also incorporates continuous conduction mode (CCM) operation, which allows it to deliver up to 225% of rated output power for a limited period without sacrificing power density. This feature is targeted at applications that require peak power, such as power adapters for laptops and notebooks.
Key features of the SZ1200 include: High frequency ACF 'CO2 Smart Power' controller; Configurable operation at high switching frequency (up to 250 kHz); Integrated primary 700V GaN FET; Integrated UHV X-cap discharge circuit, active clamp driver and startup regulator; More than 93% low line efficiency; Flat efficiency at universal input voltage (90 – 265 Vac) and load conditions; CCM for greater peak power delivery and better transformer core utilization in universal input applications; QR Valley mode switching and boosting for low-EMI and near-ZVS operation; OptiMode cycle-by-cycle adaptive digital control; Regulated burst mode; Valley detection with self-adjustment; OTP, OVP, OCP, OPP and OSCP among several other protections; Very low system no-load power consumption; Space-saving 8mm x 7mm 37-pin QFN package;
The anticipated engineering sample launch date is April 2024, with full production planned for late Q2 2024.
