AC/DC and DC/DC Solutions for Power Adapters

The batteries that power our laptops, tablets, smartphones and other portable devices must deliver ever-greater capacities if they are to meet growing demands for improved device functionality, performance and time-between-charge. At the same time, busy lifestyles demand that these higher power batteries are charged in the shortest possible time. And with much of this charging taking place ‘on-the-go’ in airports, stations, cafes or other public spaces, chargers and adapters must not only offer high power levels but must remain small enough and light enough to ensure true portability.

These conflicting requirements demand power adapters and travel adapters built on AC/DC and DC/DC power conversion schemes that can maximize operational efficiency and deliver exceptional power density. In addition, increasing concerns about no-load or ‘vampire’ power means that the underlying conversion technology must also keep power consumption as low as possible when the adapter is not charging but still connected to the wall socket.

Silanna Technology for Power Adapters

Combining optimal performance and best-in-class power density with the industry’s highest levels of integration, Silanna’s COSmart Power™  Active Clamp Flyback (ACF) AC/DC PWM controllers and high-frequency point-of-load (PoL) DC/DC converters have been designed specifically to address these challenges.

Single-Port USB-PD Travel Adapter

Multi-Port USB-PD Travel Adapter

These technologies provide power ratings of up to 100W and incorporate a variety of features that support power adapters, including unique functionality to simplify the design and optimize the performance of single-port and multi-port 30W to 100W USB-PD fast chargers.

The SZ1131 ACF controller, for example, is targeted at high efficiency and high-power density adapters of up to 65W output power with universal input and 100W output power with PFC – including single-port and multi-port USB-PD fast chargers.

Silanna Semiconductor SZ1131 AC/DC controller 65W power adapter reference design measures just 55.9mm x 25.4mm x 25.4mm

Featuring the industry’s highest level of integration, the SZ1131 is supplied in a 16-pin SOIC package and incorporates an adaptive digital PWM controller, ultra-high-voltage (UHV) active clamp FET, active clamp gate driver and startup regulator to minimize component count, BOM and size. Efficiencies of up to 95% across universal (90Vac – 265Vac) input voltages and varying loads, combined with ultra-low no-load power of less than 20mW (including USB-PD applications) significantly reduce overall energy consumption.

Among Silanna’s DC/DC conversion technologies for power adapters is the SZDL3105B, a highly integrated, wide-input, high-frequency point-of-load (PoL) converter targeted at USB-PD applications.


The SZDL3105B measures just 4mm x 4mm and is optimized for USB-PD and fast charging USB ports

Operating at a switching speed of 667kHz, the SZDL3105B buck regulator can supply up to 5A and 100W  of output power, supports inputs of up 27VDC and is supplied in a tiny 4mm x 4mm QFN package. Extremely low operating power dissipation enables the very low no-load power that is an important specification for regulatory certification. Internal and external feedback resistor divider flexibility supports custom design, while a momentary internal feedback path allows for clean and well-controlled start-up operation until external USB port controllers can bias themselves and smoothly take over control of the output voltage.

Because the SZ1130 combines industry-leading levels of integration with ultra-high-efficiency operation, the new compact, lightweight Elementech charger is up to 40% smaller than other 65W USB-PD products currently on the market.

Elementech’s new CCA-20V65W USB-PD adapter has dimensions of just 51mm x 44mm x 35mm, giving it a (cased) power density of 13.5W/inch3 (0.82W/cm3). The adapter offers a universal power (100Vac – 240Vac) input and has a maximum input current of 1.5A that automatically detects the proper charging current for connected devices. Active power distribution adjusts power sharing between the two ports. Used individually, each port can deliver 65W PD 3.0 charging. Dual-port charging delivers a maximum 63W split between 45W PD3.0 and 18W QC/15W PD. Suitable for use all over the world, the CCA-20V65W is supplied with interchangeable plugs for global compatibility.

AC/DC Products

DC/DC Products