Wide Bandgap Evolution in Power Electronics
The power electronics industry is experiencing a significant transformation with the adoption of wide bandgap (WBG) semiconductors. Silicon Carbide (SiC) and Gallium Nitride (GaN) technologies are revolutionizing power conversion efficiency, power density, and system performance across various applications.
Introduction to Wide Bandgap Semiconductors
Wide bandgap semiconductors have a bandgap energy greater than 2.0 eV, compared to silicon's 1.1 eV. This fundamental property enables several key advantages:
Higher Breakdown Voltage
WBG materials can sustain higher electric fields, allowing for higher breakdown voltages in thinner layers.
Better Thermal Conductivity
SiC, in particular, has excellent thermal conductivity, enabling better heat dissipation.
Higher Switching Frequency
Lower switching losses enable operation at much higher frequencies, reducing passive component size.
Higher Temperature Operation
WBG devices can operate at higher temperatures than silicon devices without degradation.
Silicon Carbide (SiC) Technology
SiC technology has matured significantly over the past decade and is now widely adopted in various applications:
SiC Schottky Diodes
SiC Schottky diodes offer zero reverse recovery charge, resulting in no switching losses during turn-off. This makes them ideal for high-frequency applications like PFC boost circuits where silicon diodes would suffer from significant reverse recovery losses.
SiC MOSFETs
SiC MOSFETs combine the controllability of MOSFETs with the advantageous properties of SiC material. Key characteristics include:
- Low RDS(on) compared to silicon at the same voltage rating
- Low switching losses allowing high-frequency operation
- Body diode improvements in newer designs
- High temperature operation capability
Gallium Nitride (GaN) Technology
GaN technology represents the cutting edge of high-frequency power conversion. Unlike SiC MOSFETs, enhancement-mode GaN devices have no body diode, eliminating reverse recovery losses entirely.
E-Mode GaN HEMTs
GaN devices are typically manufactured as high electron mobility transistors (HEMTs). Key characteristics include:
- Ultra-low gate charge (Qg) and output charge (Qoss)
- Zero reverse recovery charge
- Capable of very high switching speeds
- Excellent for high-frequency applications
Applications of WBG Technology
WBG semiconductors are particularly advantageous in applications that benefit from:
Fast Charging
CRMICRO's GaN solutions enable compact, high-efficiency fast chargers for mobile devices and laptops.
Electric Vehicles
SiC power devices improve the efficiency and power density of OBCs, DC-DC converters, and traction inverters.
Photovoltaic Inverters
WBG devices improve efficiency in solar power systems, increasing energy harvest.
Industrial Power Supplies
Higher switching frequencies reduce passive component size and system volume.
CRMICRO's WBG Portfolio
CRMICRO offers a comprehensive portfolio of wide bandgap devices designed for various applications. Our SiC and GaN offerings include:
- SiC Schottky diodes in various voltage and current ratings
- SiC MOSFETs from 650V to 1700V with excellent figure of merit
- Enhancement-mode GaN HEMTs for ultra-high-frequency applications
Each device is designed with application-specific parameters in mind, ensuring optimal performance in targeted applications.
Design Considerations for WBG Devices
While WBG devices offer significant advantages, they also require some design considerations:
Gate Drive Requirements
WBG devices often require specific gate drive techniques compared to silicon MOSFETs. SiC MOSFETs, for example, typically require negative gate drive for turn-off to ensure reliable operation.
Parasitic Inductance
The high switching speeds of WBG devices can cause significant voltage overshoots due to parasitic inductance. Careful PCB layout and packaging are critical.
Thermal Management
While WBG devices can operate at higher temperatures, thermal management remains important for long-term reliability and optimal performance.
Future of WBG Technology
The wide bandgap semiconductor market continues to grow rapidly. Key trends include:
- Improvement in substrate quality and reduction in cost
- Development of new device structures and packages
- Integration of WBG dies with drive and protection circuitry
- Expansion to new applications and voltage classes
CRMICRO remains committed to advancing WBG technology, with ongoing R&D efforts focused on improving performance, reliability, and cost-effectiveness of our devices.
Technical Note from our FAE
When transitioning from silicon to WBG devices, engineers should pay particular attention to gate drive design. SiC MOSFETs often require different gate drive requirements than silicon devices, including negative turn-off voltage and careful consideration of gate resistance for optimal switching characteristics. CRMICRO provides reference designs and gate drive recommendations for all our WBG devices.