Reference design supports development of efficient all-silicon chargers

11-01-2022 | Silanna Semiconductor | Design & Manufacture

Silanna Semiconductor has released a new ACF-based reference design that simplifies and hastens the development of 33W 1C fast charger applications created employing silicon power FETs. Providing the company’s latest SZ1131 CO2 Smart Power ACF controller technology, the RD-23 offers a route to providing a performance that matches or surpasses that of commercially available 30W GaN-based chargers at a cost more often associated with traditional silicon designs.

The new device includes everything an engineer requires to prototype and create a fully functional charger with low operational and no-load/standby power consumption and minimum component count, BOM cost and size. It employs the SZ1131 – the company’s newest ACF controller, which is rated for 65W for universal input and above 100W with PFC-supported applications. This controller provides the industry’s highest level of integration by including an adaptive digital PWM controller, 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 device functions with a peak efficiency of over 92% and has a no-load power consumption (@ 230VAC) below 20mW. Efficiency is flat over the universal input (90-65VAC) input range, and the reference design is fully production-ready as it surpasses conducted and radiated EMI requirements by over 6dB margins.

“The RD-23 is the latest in a series of silicon- and GaN-based reference designs that Silanna has created to help engineers quickly and easily develop the industry’s most efficient and highest power density chargers,” comments Ahsan Zaman, Silanna Semiconductor’s director of product marketing. “In our benchmarking tests the RD-23 met and exceeded both the efficiency and no-load vampire power consumption of the best-in-class commercially available GaN-based power adapters. RD-23 demonstrates GaN-level performance at silicon-level costs.”

The SZ1131 operates at frequencies of up to 146kHz and gives the ease-of-design of a simple flyback controller including the benefits of an ACF design. This incorporates recycling the leakage inductance energy of the flyback transformer and limiting the primary FET drain voltage spike during turn-off events. Employing the company’s OptiMode digital control architecture, it 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.

Provided in a 16-pin SOIC package, the SZ1131 delivers protection against over-temperature, over-current, over-voltage, over-power and short circuit conditions, and transformer core saturation fault with no need for extra external components.

To further speed designs based on the RD-23 all PCB Gerber files and production files are available on request.

By Natasha Shek