Silanna Semiconductor has launched a new active clamp flyback (ACF)-based reference design that simplifies and speeds the development of 33W 1C fast charger applications built using silicon power FETs. Featuring the company’s latest SZ1131 CO2 Smart Power ACF controller technology, the Silanna Semiconductor RD-23 provides a route to delivering a performance that matches or exceeds that of commercially available 30W GaN-based chargers at a cost more readily associated with conventional silicon designs.
Silanna’s new RD-23 incorporates everything an engineer needs to prototype and develop a fully functional charger with low operational and no-load/ standby power consumption and minimum component count, BOM cost, and size. RD-23 uses the SZ1131 – Silanna Semiconductor’s newest ACF controller, which is rated for 65W for Universal input and above 100W with PFC-supported applications. This controller offers the industry’s highest level of integration by incorporating an adaptive digital PWM controller, ultra-high-voltage (UHV) active clamp FET, active clamp gate driver, and startup regulator into a single compact device.
Providing an (uncased) power density of 22W/inch3, the RD-23 operates with a peak efficiency of over 92% and has a no-load power consumption (@ 230Vac) below 20mW. Efficiency is flat across the universal input (90 – 265Vac) input range and the reference design is fully production-ready as it exceeds conducted and radiated EMI requirements by more than 6dB margins.
The SZ1131 operates at frequencies of up to 146kHz and provides the ease-of-design of a simple flyback controller with all the benefits of an ACF design. This includes recycling the leakage inductance energy of the flyback transformer and limiting the primary FET drain voltage spike during turn-off events. Employing Silanna Semiconductor’s OptiModeTM digital control architecture, the SZ1131 adjusts the device’s mode of operation on a cycle-by-cycle basis to maintain high efficiency, low EMI, fast dynamic load regulation, and other key power supply parameters in response to varying line voltage and load.
Supplied in a 16-pin SOIC package, the SZ1131 offers protection against over-temperature, over-voltage, over-current, over-power, and short circuit conditions, as well as transformer core saturation fault without the need for additional external components. To further speed designs based on the RD-23 all PCB Gerber files and production files are available on request.