Pulsiv recently released a new USB-C reference design intended to set a new standard in the fast-charging space. This release responds to the need for size-constrained, efficient charging technologies for the proliferating smartphones, laptops, and other portable devices.
USB-C cables are commonly rated for 10-Gbps speeds. Image used courtesy of Canva Pro (under license)
Many companies, like Pulsiv, are now innovating intelligent power management systems, incorporating sophisticated control algorithms, and leveraging materials like gallium nitride (GaN) to push the boundaries of power delivery.
Pulsiv’s 65-W, USB-C Reference Design
The PSV-RDAD-65USB reference design (datasheet linked) is a comprehensive 65-W, USB-C AC-to-DC power supply solution that targets the increasing demand for efficient, compact, and reliable power solutions, particularly for USB-C applications. The design supports fast charging standards such as PD3.0, QC4.0, BC1.2, and PPS.
At the heart of the design is Pulsiv’s patented Osmium technology, an AC-to-DC, front-end conversion method that integrates intelligence with an active valley-fill approach. This method optimizes performance, especially at low loads, by improving the average efficiency and reducing energy consumption. It also ensures a flat efficiency profile across all load conditions.
Pulsiv Osmium high-side architecture.
On a deeper level, the PSV-RDAD-65USB utilizes a quasi-resonant (QR) flyback topology known for its ability to provide high efficiency and low electromagnetic interference (EMI). The core components include the Pulsiv Osmium microcontroller (PSV-AD-65EG-Q24IV), onsemi’s NCP1342 flyback controller, and Innoscience’s gallium nitride (GaN) transistors.
Integrating GaN transistors into the design reduces both RDS(on) and parasitic capacitance, major factors in minimizing power losses. This, combined with the unique magnetics developed in collaboration with Frenetic, allows the design to achieve a 20% reduction in transformer size and a 50% improvement in efficiency compared to conventional designs.
Half-Active Bridge and Performance
The reference design takes a half-active bridge rectification approach, eliminating the need for a full-wave diode bridge. Pulsiv claims that this configuration reduces peak line currents by up to 90% to significantly lower RMS values and minimize losses. Functionally, the circuit intelligently controls the charging of a storage capacitor using a high-side architecture, allowing the use of lower voltage capacitors (160 V or 200 V).
Pulsiv’s half-active bridge control.
Efficiency measurements across different output voltages and load conditions indicate that the design maintains high efficiency even at partial loads. For instance, at 230 VAC input and 20 V / 3.25 A output (65 W), the efficiency peaks at 96.03%, with a four-point average efficiency of 95.20%. Meanwhile, the design is compact, with mechanical dimensions of 155 mm x 52 mm x 35 mm and a weight of just 80 g.
Charging Ahead
The release of Pulsiv’s 65 W, USB-C reference design reflects a trend toward highly efficient, compact, and adaptable power solutions. As power demands continue to escalate, integrating advanced technologies like GaN and intelligent control algorithms will likely become the norm. Looking ahead, Pulsiv is developing fully assembled, size-optimized, and EMC-compliant plug-and-play modules to further simplify adoption. These modules are expected to be available for pre-order through franchised distribution partners, with deliveries anticipated in Q4 2024.
All images used courtesy of Pulsiv.
