Xinleineng SiC Modules

SiC MOSFET modules offer significant advantages over IGBT modules: 1) Higher switching frequencies - SiC can switch at 50-100kHz vs 20kHz for IGBT, enabling smaller filters and magnetics

2) Lower switching losses - SiC has 30-50% lower switching losses, improving system efficiency by 2-5%

3) No tail current - SiC MOSFETs turn off cleanly without the current tail of IGBTs, reducing turn-off losses

4) Higher temperature capability - SiC operates up to 175C junction vs 150C for IGBT

5) Lower conduction losses at light load - SiC maintains low on-resistance across load range vs increasing Vce(sat) of IGBT. These advantages enable higher power density, reduced cooling requirements, and improved system efficiency.

For applications above 20kHz switching frequency or requiring efficiency above 98%, SiC modules provide significant system-level benefits.

SiC MOSFET modules require different gate drive voltages than IGBTs. Recommended gate drive: +18V to +20V for turn-on (vs +15V for IGBT) to achieve lowest on-resistance specified in datasheet. -2V to -4V for turn-off to prevent false turn-on from dv/dt coupling through Miller capacitance. Some designs use +15V/-4V for compatibility with existing IGBT drivers, though this results in slightly higher on-resistance. The higher positive voltage is critical because SiC MOSFETs need strong gate drive to fully enhance the channel - operating at +15V instead of +20V can increase on-resistance by 20-30%. Gate threshold voltage is typically 2.5-3.5V, much lower than IGBT's 5-6V, making SiC more susceptible to dv/dt turn-on.

Use gate drivers specifically designed for SiC MOSFETs with +18V/-4V output and active Miller clamp for best performance.

SiC MOSFET conduction loss calculation is simpler than IGBT because SiC behaves like a resistor (ohmic) rather than a diode with offset voltage. Conduction loss formula: Pcond = I^2 x Rds(on) x D, where I is RMS current, Rds(on) is on-resistance at operating temperature, and D is duty cycle. Important: Rds(on) increases with temperature - typically 1.5x at 100C and 2x at 150C compared to 25C value. For XLN80M120-SiC with 80mOhm at 25C, expect approximately 120mOhm at 100C junction temperature. At 50A RMS current and 50% duty cycle: Pcond = 50^2 x 0.12 x 0.5 = 150W. This is typically lower than IGBT conduction losses at equivalent current due to lower voltage drop at high currents.

Our FAE team can provide detailed loss calculations including temperature effects for your specific operating conditions.

SiC module PCB layout requires special attention due to high dv/dt and di/dt: Minimize gate loop inductance - keep gate traces short and wide, use gate driver placed close to module. Use Kelvin source connection - separate power source (carrying load current) from gate drive source reference to avoid common source inductance. Minimize DC bus inductance - use laminated busbars or parallel copper planes for low inductance connection to DC link capacitors. Place decoupling capacitors close to module - use 1-10uF high-frequency film capacitors right at module terminals. Implement proper shielding - high dv/dt can couple noise into control circuits

use proper grounding and shielding techniques. These measures are critical because SiC's fast switching (dv/dt up to 50V/ns) can cause significant ringing and EMI if layout is not optimized.

Contact our FAE team for detailed PCB layout guidelines and review services for SiC designs.

SiC modules require specific protection considerations: Gate overvoltage protection - SiC gate oxide is thinner and more sensitive to overvoltage

use clamping diodes or active clamping to limit gate voltage to +/-25V absolute maximum. dv/dt induced turn-on - SiC's low threshold voltage (2.5-3.5V) makes it susceptible to Miller effect

use negative turn-off voltage (-2V to -4V) and/or active Miller clamp. Short-circuit protection - SiC has lower short-circuit withstand time than IGBT (typically 2-5us vs 10us)

protection must be faster with desaturation detection responding within 1-2us. Overcurrent protection - SiC does not saturate like IGBT, so current limiting or fuses are needed for overcurrent protection. Thermal protection - SiC can operate at higher temperatures (175C) but reliability is improved by keeping junction below 125C.

Our FAE team can review your protection circuit design for SiC-specific requirements and recommend appropriate protection schemes.