Since the 1960s, silicon-based MOSFETs have been the standard in power electronics. However, the demand for higher efficiency and power density in smaller sizes has posed new challenges. Power supplies, from data centers to automotive charging stations, need high voltage while minimizing PCB space. As silicon semiconductors reach their limits, Gallium Nitride (GaN) is emerging as the optimal solution for these needs. Many distributors offer a wide range of electronic components to cater to diverse application needs, like BTS50085-1TMA
Understanding GaN HEMT
GaN HEMTs (High Electron Mobility Transistors) may not always outperform Si MOSFETs, SiC MOSFETs, or IGBTs (Insulated Gate Bipolar Transistors) in every application. However, they are particularly well-suited for high-frequency, medium-voltage applications. For instance, 600V GaN FETs are commonly used in power supplies for consumer electronics, base stations, and wireless charging systems. In contrast, SiC MOSFETs can handle voltages up to 1200V, making them more suitable for high-current applications like automotive traction inverters and large solar plants.
While GaN FETs offer lower power output compared to SiC MOSFETs, their higher switching frequencies (greater than 200 kHz) allow for faster switching and lower conduction losses. GaN HEMTs offer similar power density to traditional Si MOSFETs but excel in high-frequency operation, making them ideal for wireless charging. SiC MOSFETs and IGBTs, on the other hand, are better for high-power applications with lower efficiency requirements, such as electric vehicles, large industrial machinery, and power-hungry server farms.
Cost-Effectiveness and Manufacturing
GaN HEMTs are smaller and more cost-effective than traditional MOSFETs. The raw materials used in GaN technology are also significantly cheaper than those for SiC devices. Producing GaN requires less energy than SiC, leading to substantial energy savings for manufacturers. Additionally, GaN devices are developed on silicon substrates, allowing for the use of existing production methods with minimal modifications.
Compared to SiC MOSFETs, GaN HEMTs offer higher efficiency, generate less heat, and require less cooling. This reduces energy consumption during operation and helps save customers additional costs.
Challenges with GaN HEMT
A drawback of GaN HEMTs is their narrow optimal drive voltage range, typically between 4.5V and 6V. If the voltage is too low (below 2V), the device may fail to turn off, and if too high, it could damage the gate. While using an external gate driver can optimize performance, it occupies additional PCB space. However, GaN HEMTs generate less heat and require less cooling than silicon-based devices, potentially reducing energy and maintenance costs for customers.
Overcoming Limitations with Integrated GaN HEMTs
The challenges of discrete GaN HEMTs can be overcome, offering several advantages. GaN HEMTs can be integrated with other circuits on the same substrate, allowing for additional features like protection circuits. Integrated solutions are more cost-effective, save PCB space, reduce parasitic effects, and simplify layouts.
From a performance perspective, integrated solutions can maintain or even enhance the high-frequency benefits of GaN HEMTs, compared to multi-device setups. Additionally, reliability is improved, which is crucial for power delivery applications.
Conclusion
In conclusion, GaN HEMTs represent a promising frontier in power semiconductor technology, offering efficiency improvements and cost advantages for a wide range of applications, from consumer electronics to power delivery systems.