This design employs advanced technologies like gallium nitride (GaN) FETs for high switching frequencies, reducing the size of components such as transformers and capacitors while enhancing efficiency.
Notebook PCs and smartphones rely on adapters to charge their batteries efficiently. USB Power Delivery (PD) negotiation enables these devices to establish a power contract, ensuring the optimal power level is delivered based on the battery’s conditions. This protocol supports up to 100 W (20 V, 5 A) power delivery, facilitating rapid and efficient charging. High efficiency and compact design are crucial to conserving energy and enhancing the portability of these adapters.
A notebook adapter functions as an AC/DC converter, often requiring a power factor correction (PFC) stage for output power exceeding 75 W. This reference design provides a high-efficiency, high-power-density AC/DC adapter solution with a broad input voltage range of 100-240 V AC, making it suitable for both laptop adapters and smartphone chargers. The design features a front-end transition-mode (TM) PFC circuit powered by the UCC28056 controller, followed by an active-clamp flyback isolated DC/DC converter utilizing the UCC28780 controller.
The adapter delivers key features such as a wide input range (100-240 V AC) and configurable outputs, including 5 V/5 A, 9 V/5 A, 15 V/5 A, and 20 V/5 A. It achieves a peak efficiency of 93.4% with natural cooling and boasts a compact size of 70 mm × 42 mm × 16.5 mm with a power density of 30 W/in³. Additionally, it consumes less than 130 mW in standby mode, making it highly energy-efficient.
Synchronous rectification using the UCC24612 controller further improves performance. Built-in protection mechanisms safeguard against over-current, over-power, and over-voltage conditions, ensuring the safety of connected devices. The adapter automatically recovers from faults like short circuits and over-power events, while over-voltage conditions trigger a latch to prevent damage.
Validated for performance metrics such as regulation, ripple, and switching stresses, this 100-W AC/DC adapter delivers reliable and efficient power in a compact form factor, meeting global efficiency standards and addressing the challenges of modern adapter designs.
Texas Instruments (TI) has tested this reference design. It comes with a bill of materials (BOM), schematics, assembly drawing, printed circuit board (PCB) layout, and more. The company’s website has additional data about the reference design. To read more about this reference design, click here.
