In the ever-evolving realm of power supply technology, the advent of gallium nitride (GaN) components stands as a beacon of disruptive innovation. Revolutionizing power transistors with significant efficiency improvements, GaN doesn't just shrink the size of power supplies; it cools their operating temperatures too—a boon for design engineers weaving GaN into the fabric of flyback AC/DC power supplies across diverse applications.
Transistors, whether silicon-based or GaN-crafted, face inherent efficiency ceilings. The crux of this limitation? Two pivotal factors: series resistance (RDS(ON)) and parallel capacitance (COSS). These parameters, traditionally, handcuff power supply performance. Enter GaN technology: a game-changer. GaN transistors not only pare down RDS(ON) but do so while keeping their COSS increase ratio substantially below their traditional counterparts. This unique trait forges a more harmonious balance between these parameters in design.
Digging deeper into the interplay of RDS(ON) and COSS, GaN's superiority emerges. RDS(ON) signifies resistance during switch activation, directly influencing conduction loss. Contrastingly, COSS's power loss follows the CV^2/2 equation. When active, COSS discharges through RDS(ON), spawning additional losses. GaN switches, replacing silicon, slash these losses, propelling power efficiency, embracing higher frequency operations, and shrinking transformers.
But there's more. Consider the influence of transistor size on RDS(ON) and COSS. Larger transistors mean lower RDS(ON)—a positive. Yet, this size increase inflates COSS, a less than ideal twist. Optimal design, therefore, seeks a delicate equilibrium between these factors at minimal loss. GaN transistors excel here, handling equivalent power levels as larger silicon devices, yet at reduced sizes, courtesy of their drastically lower specific RDS(ON).
To sum up, GaN melds lower RDS(ON) with COSS to forge more efficient power supplies. This not only eases heat dissipation but also trims size and weight. Moreover, GaN's efficiency lets designers boost switching frequencies, which, though escalating losses, remain significantly beneath silicon MOSFETs.
Take Keep Tops' GaN application: their ≤100W GaN-based flyback adapter melds high efficiency with optimized size and cost. Here, GaN transcends switching speed limits, granting designers newfound leeway in frequency tuning to minimize losses for more efficient solutions.
Moreover, the potency of GaN in augmenting power efficiency is unmissable. A case in point: Keep Tops' 65W flyback adapter, switching from silicon MOSFETs to GaN-based InnoSwitch devices, showcased a roughly 3% efficiency leap across all loads. This boost is monumental, slashing energy use, cutting heat, downsizing cooling needs, and compacting the power supply—all while prolonging its lifespan.
In practical GaN transistor applications, Keep Tops has carved its niche with a unique design ethos. GaN transistor driving poses challenges, especially when the driver circuit is distanced from the transistor, demanding intricate designs to dodge electromagnetic interference. To combat this, PI introduced the InnoSwitch3 series. These integrated flyback switch ICs come with in-built controllers for GaN primary and secondary rectifiers and are equipped with FluxLink technology, ensuring safe feedback transmission and insulation.
InnoSwitch3-PD, the family's latest addition, boasts primary and secondary controllers and GaN master switches. It provides full USB PD and PPS interface capabilities. PI's InnoSwitch3-Pro and InnoSwitch3-MX, among other GaN products, continue to offer tailored solutions for varying needs.