Pulsiv Limited, a Cambridge, UK innovator of power electronics technology, has developed what it says is the world’s most efficient 65W USB-C GaN optimized reference design to address the complex challenges associated with thermal performance in power supplies. Highly optimized ultra-compact magnetics from Frenetic help make the breakthrough possible.
The advancement could revolutionize the USB-C fast charging space by offering a unique combination of features and benefits not seen in other designs. The PSV-RDAD-65USB reference design combines Pulsiv OSMIUM technology with an industry standard QR Flyback and the specially designed magnetic elements. It represents the first in a series of designs aimed at pushing the boundaries of power conversion by drastically lowering operating temperatures, minimizing losses, and reducing size to create a sustainable platform for the USB-C standard.
“Our mantra has always been focused on developing solutions that ‘do more while using less’ and this design demonstrates how Pulsiv OSMIUM technology can deliver fast charging without the associated complexity of managing high temperatures,” explains Dr. Tim Moore, chief product officer for Pulsiv. “The demand for more power and faster charging of cordless products is rapidly increasing which impacts everything from mobile phones to power tools. This means more power is needed in a small form factor which is even more critical when developing in-wall/desk solutions which are sensitive to heat. With 30% lower component temperatures, no inrush current, and high efficiency, we enable designs to become safer, smaller, and be more reliable.”
The Pulsiv OSMIUM reference design demonstrates a significant improvement in thermal performance and reduces critical component temperatures by more than 30% compared to other designs. At full load, the Flyback transformer reaches an impressive 33.9°C at 230VAC and 30.3°C at 265V above an ambient temperature of 26.1°C. Likely setting a new benchmark, it enables 65W fast charging in space constrained environments and heat sensitive applications such as in-wall plug sockets that incorporate USB-C connectivity.
Optimize efficiency and space with a half-active bridge
Pulsiv Osmium technology senses AC line voltage and frequency to adjust capacitor charging time, therefore the circuit draws no line current at the AC zero voltage crossing. This enables a simple half-active bridge implementation to increase efficiency, especially at low line conditions. Mosfets in the lower half of the AC to DC bridge are carefully controlled, in combination with high-side diodes. The half-active bridge in this design strikes the delicate balance between efficiency, cost, and complexity and supports universal input with efficiency gains of 0.7% at full load from a 115V AC supply.
Innovative magnetics reduce transformer size by 20%
The Osmium technology generates a HVDC output that varies between the peak AC input and 150V to drive the QR Flyback at maximum efficiency. The wider voltage range significantly reduces primary side inductance to enable the use of an EQ20 transformer which was developed in partnership with magnetics company Frenetic, based in Madrid.
“Our team of magnetics experts have demonstrated that Pulsiv Osmium technology maximises efficiency and reduces the size of the flyback transformer to a level we’ve not seen before,” notes Chema Molina, CEO of Frenetic. “This significant development will enable customers to improve performance, reduce size, and lower the cost of their design and we’re excited to be part of such an innovative solution”. As a result, size is reduced 205 and efficiency improved 50% compared to an RM8 core typically used in other designs.
GaN optimization minimizes losses
GaN transistors from Innoscience have lowered the RDSon and parasitic capacitance to reduce losses and optimize cost in both the flyback and synchronous rectifier sub-systems, according to Pulsiv. General Manager for Innoscience EMEA Denis Marcon, adds: “We’ve demonstrated that GaN technology is perfectly suited to increasing efficiency, reducing losses, and optimising cost but Pulsiv Osmium technology adds further benefits by significantly improving the overall performance and reducing energy waste. Their technology is truly game-changing, and I’m delighted that Pulsiv has chosen to incorporate Innoscience GaN devices in this reference design.” In other applications, GaN devices from Innoscience are used to boost efficiency of drivers and controls in permanent magnet motors for the electric vehicle market, also for magnetic field transfer of energy in wireless charging systems.
For more info, see www.pulsiv.com, www.frenetic.ai, www.innoscience.com.
