Silanna extends all-silicon reference design family to 65W

2 min read

Silanna Semiconductor has launched an active clamp flyback (ACF)-based reference design that simplifies the development of 65W 1C fast charger applications built using silicon power ICs.

Featuring the company’s CO2 Smart Power ACF controller technology, the RD-31 provides a route to delivering performance that matches commercially available 65W GaN-based chargers at a cost on a par with conventional silicon designs.

The RD-31 is the latest in a family of production-ready reference designs that enables prototyping and allows the development of a fully functional charger with low operational and no-load/ stand-by power consumption and minimum component count and size. This family includes all-silicon 33W and GaN-based 65W USB-PD reference designs.

As with the company’s existing silicon reference designs, the RD-31 is based on the ultra-high-efficiency SZ1131 ACF controller, which is rated for 65W and above 100W operation in universal input and PFC applications, respectively. This controller offers a high level of integration by incorporating an adaptive digital PWM controller, ultra-high-voltage (UHV) active clamp FET, active clamp gate driver and start-up regulator into a single compact device.

Providing an (uncased) power density of 30W/inch3, the RD-31 operates with a peak efficiency of around 94% and has a no-load power consumption below 25mW.

Efficiency is flat across the universal input voltage range (90 – 265Vac) and the reference design is fully production-ready as it exceeds conducted and radiated EMI requirements by more than 6dB. In benchmarking tests, the RD-31 exceeded the efficiency of the best-in-class commercially available GaN-based power adapter by 0.5% and reduced no-load vampire power by as much as 44%.

“We are committed to helping engineers deliver high-performance chargers with ever higher power densities by developing technologies that increase operational efficiency and reduce vampire power,” said Ahsan Zaman, Silanna Semiconductor’s director of product marketing. “By building production-ready reference designs around these technologies we are also simplifying the design-to-manufacturing cycle to ensure these advanced charger designs move to production in the shortest possible time.”

The SZ1131 operates at frequencies up to 146kHz enabling the 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’s OptiMode 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 conditions.

Supplied in a 16-pin SOIC package, the SZ1131 offers protection against over-temperature, over-voltage, over-current, over-power, output short circuit, and transformer core saturation faults without the need for additional external components.

All PCB Gerber files and production files are available on request.