Nix the Heat Sink: New GaN ICs Aim to Slim Down Power Supply DesignMay 25, 2021 by Jake Hertz
Yesterday, Power Integrations released a new family of flyback controller ICs which leverage GaN technology for maximize efficiency. Could this help push GaN further mainstream?
The rise to prominence of GaN as a viable semiconductor material has led to significant changes in many parts of the power industry.
One application that has seen marked improvements thanks to GaN is mobile chargers. Not only does GaN make these devices more efficient, but this increased efficiency also removes the need for space-consuming heatsinks, allowing chargers to be smaller and more power-dense.
Yesterday, Power Integrations (PI) released a new family of flyback controller ICs that leverage GaN to maximize efficiency.
This article will discuss challenges with integrating GaN, how PI’s new ICs address these problems, and how the new family is already being utilized in the industry.
Challenges of Integrating GaN
While much of what you read about GaN makes it sound like a magical solution, the truth is that it's not all that straightforward to use. As Jim Witham, CEO of GaN Systems, puts it, "GaN is like a Ferrari––you have to learn how to drive it."
One of the major challenges for integrating GaN is how to drive the device properly. Since GaN is significantly faster than Si, the timing control needed by the driver has a minimal margin of error.
Having controllers with these tight timing restrictions is hard enough as it is, but another result of this is that board-level parasitics suddenly play a crucial role. Even the smallest amount of parasitic inductance or capacitance can be enough to make GaN challenging to drive.
GaN vs Si FET performance. Image used courtesy of Power Integrations
Another issue with GaN is that its high switching speed can easily result in a high current rate-of-change (di/dt), leading to high-frequency oscillation during switching.
These results can often lead to EMI, lower efficiency, and potentially damage to the device. GaN's high switching speeds make it very difficult to detect fault conditions quickly enough, resulting in destructive currents before any safety features can appropriately respond.
How PI’s New Family Addresses These Problems
Using PI's "PowiGaN" technology resolves these problems by integrating its GaN devices onto its controller ICs. The integration significantly reduces parasitic inductances and capacitances, making it easier to meet timing restrictions and avoid oscillations.
PI's new IC family incorporates drivers tuned to the specific device, allowing them to optimize switching speed for minimal EMI, maximum efficiency optimizing switching speed for minimum EMI, maximum efficiency, and effectively eliminating oscillation.
Further, the new family includes protection circuitry that can quickly detect and respond to unsafe currents to shut down devices under fault conditions safely.
A schematic of InnoSwitch4-CZ. Image used courtesy of Power Integrations
When used with its ClampZero active clamp IC, the InnoSwitch 4-CZ family can perform variable frequency asymmetrical control of the active clamp. This ability allows for discontinuous and continuous conduction modes of operation, improving design flexibility and maximizing efficiency, reaching up to 95% across variations in line voltage, system load, and output voltage.
Impact on the Industry
PI's new controller IC family is already finding good use in the industry, as Anker has put it into its new Nano II chargers. Combining PI's InnoSwitch 4-CZ and its ClampZero technologies, the Nano II achieves impressive specs, providing up to 65W of power in an area almost 60% smaller than comparable devices.
Anker’s Nano II, which utilizes PI’s new offerings, can provide 60W of power in an area 58% less than competitors. Image used courtesy of Anker
By solving GaN's design challenges through integration, PI can successfully harness the immense benefits of GaN in the InnoSwitch 4-CZ family. While it isn't the only company to do it, the implications of bringing GaN to market are huge and could help catalyze improvement in power electronics.