With the advent of urban air mobility and the stringent certification of street-legal personal flying vehicles, the electrified powertrain and avionics systems have become the core of vehicle performance and safety. The power semiconductor devices, serving as the "muscles and nerves" of the propulsion, power distribution, and safety systems, provide robust and efficient switching for critical loads such as lift/thrust motors, high-power avionics, and emergency isolation circuits. The selection of MOSFETs and IGBTs directly determines the system's power-to-weight ratio, thermal resilience, electromagnetic compatibility (EMC), and functional safety. Addressing the extreme demands of flying cars for high efficiency, ultra-reliability, compactness, and operation under harsh environmental conditions, this article develops a scenario-based, optimized device selection strategy.
I. Core Selection Principles and Scenario Adaptation Logic
(A) Core Selection Principles: Multi-Dimensional Co-Design
Device selection requires a holistic co-design across four dimensions—voltage ruggedness, switching/conductive loss, package/power density, and automotive-grade reliability—ensuring survival in demanding aerial and road conditions.
Voltage Ruggedness with High Margin: For high-voltage traction buses (e.g., 400V or 800V), select devices with a rated voltage exceeding the maximum bus voltage by ≥100% to withstand load dump, switching spikes, and regenerative braking surges. For auxiliary 12V/48V rails, a ≥50% margin is mandatory.
Ultra-Low Loss for Range & Thermal Management: Prioritize devices with minimal conduction loss (low Rds(on) or VCEsat) and optimized switching figures (low Qg, Eoss) to maximize drive efficiency, extend flight/range time, and minimize heatsink weight.
Package for Power Density & Cooling: Choose packages like TO247 or high-performance modules for multi-kilowatt propulsion inverters, ensuring low thermal resistance. Utilize compact packages like DFN or SOT for distributed point-of-load (POL) converters, optimizing board space and weight.
Automotive-Grade Reliability & Robustness: Mandate AEC-Q101 qualification or equivalent, wide junction temperature range (e.g., -55°C ~ 175°C), high immunity to avalanche and short-circuit events, and excellent thermal cycling performance to endure vibration and climatic extremes.
(B) Scenario Adaptation Logic: Categorization by Criticality
Divide applications into three core, safety-impacting scenarios: First, the Propulsion Inverter (Power Core), requiring ultra-high current, high voltage, and fault-tolerant operation. Second, the Auxiliary Power Distribution & Management (Functional Support), requiring high-density, efficient power routing and switching for avionics, sensors, and actuators. Third, Safety-Critical Isolation & Backup Systems, requiring fail-safe isolation of faulty segments and robust operation of backup power paths.
II. Detailed Device Selection Scheme by Scenario
(A) Scenario 1: Propulsion Inverter (20-100kW) – Power Core Device
Lift and thrust motor drives require handling high continuous and peak phase currents, high DC bus voltages, and high switching frequencies for precise torque control and acoustic noise reduction.
Recommended Model: VBP16I60 (IGBT with FRD, 600V/650V, 60A, TO247)
Parameter Advantages: Field-Stop (FS) IGBT technology offers an optimal balance between low saturation voltage (VCEsat=1.7V @15V) and switching loss at high currents/voltages, ideal for 400V-600V bus systems. Integrated Fast Recovery Diode (FRD) simplifies inverter leg design. 60A continuous current (with appropriate derating) suits mid-power propulsion units. TO247 package provides excellent thermal interface for heatsinking.
Adaptation Value: Enables efficient high-power motor control with lower conduction loss than standard planar MOSFETs at this voltage/current level. Robustness against short-circuit events enhances system safety. Contributes to a high system power density crucial for vehicle weight.
Selection Notes: Verify peak motor current and worst-case junction temperature. Requires gate driver with negative turn-off voltage (e.g., -5V to -8V) for reliable operation and minimized turn-off loss. Parallel devices may be needed for higher power levels. Careful layout of DC-link capacitors is critical to minimize stray inductance.
(B) Scenario 2: Auxiliary Power Distribution & POL – Functional Support Device
Numerous low-to-medium power loads (Flight Controller, LiDAR, Radios, Servos) require efficient, compact, and intelligent power switching/conditioning from 12V/48V rails.
Recommended Model: VBQD3222U (Dual N-MOS, 20V, 6A per channel, DFN8(3x2))
Parameter Advantages: Ultra-low threshold voltage (Vth as low as 0.5V) enables direct drive from low-voltage MCUs (1.8V/3.3V logic) without level shifters, simplifying control. Exceptionally low Rds(on) of 22mΩ at 4.5V minimizes conduction loss. Dual N-channel in a tiny DFN8 package saves over 70% board area compared to discrete solutions, maximizing power density.
Adaptation Value: Enables high-frequency, high-efficiency synchronous rectification in DC-DC POL converters. Perfect for intelligent load shedding, sequenced power-up, and protecting sensitive avionics. Low gate drive requirements reduce MCU load and system complexity.
Selection Notes: Ensure total power dissipation per channel is within package limits with adequate copper pour. Add small gate resistors (1-10Ω) to dampen ringing. Consider using both channels in parallel for loads up to 10-12A.
(C) Scenario 3: Safety-Critical Isolation & High-Voltage Switching – Safety Device
Systems require guaranteed isolation of faulty high-voltage modules (e.g., a failing battery segment) and reliable switching for backup power paths or high-voltage auxiliary loads.
Recommended Model: VBL185R05 (Single N-MOS, 850V, 5A, TO263)
Parameter Advantages: Very high drain-source voltage rating (850V) provides substantial margin for 400V-600V systems, easily absorbing transients. Planar technology offers proven robustness and stability. TO263 (D2PAK) package balances good power handling with a lower profile than TO247.
Adaptation Value: Serves as a reliable, solid-state isolation switch in battery management system (BMS) disconnect units or contactor replacement circuits. Can be used to control high-voltage auxiliary pumps or fans. Its high voltage rating ensures system integrity during fault conditions.
Selection Notes: Switching speed is secondary to ruggedness in this role. Use a dedicated high-side gate driver (e.g., bootstrap or isolated) for control. Implement robust overcurrent sensing on the load side. Ensure proper creepage and clearance distances for the high voltage.
III. System-Level Design Implementation Points
(A) Drive Circuit Design: Matching Device Characteristics
VBP16I60: Pair with automotive-grade IGBT gate drivers (e.g., ISO5852S, 2.5A/5A peak) featuring DESAT protection, soft turn-off, and negative bias supply. Use low-induance gate drive loops.
VBQD3222U: Can be driven directly from MCU GPIOs. For optimal switching, a small gate driver buffer (e.g., TC4427) is recommended. Implement individual gate resistors for each channel if switching asynchronously.
VBL185R05: Requires a high-voltage isolated gate driver (e.g., Si8239x) for high-side switching. Include a Zener clamp (e.g., 15V) between gate and source for protection.
(B) Thermal Management Design: Mission-Critical Cooling
VBP16I60: Mount on a liquid-cooled or forced-air heatsink. Use thermal interface material (TIM) with low thermal resistance. Monitor case temperature directly with a sensor.
VBQD3222U: Provide a symmetric, generous copper pad (≥30mm² per channel) on the PCB connected with multiple thermal vias to internal ground planes for heat spreading.
VBL185R05: Mount on a dedicated area of the main board with a large copper pour or connect to a chassis heatsink via the package tab.
Overall: Implement redundant temperature monitoring for propulsion inverter devices. Ensure airflow is not obstructed in any flight or ground orientation.
(C) EMC and Functional Safety (FuSa) Assurance
EMC Suppression:
VBP16I60: Use low-induance DC-link capacitor banks. Implement RC snubbers across each IGBT if needed. Shield motor cables.
VBQD3222U: Use local ceramic decoupling capacitors (100nF + 10µF) at the drain of each switch. Add ferrite beads in series with power inputs to sensitive loads.
General: Implement strict zoning: separate high-power, high-speed switching areas from sensitive analog/RF areas. Use common-mode chokes on all external cable interfaces.
Reliability & Protection:
Derating: Apply stringent derating: voltage ≤70%, current ≤50-60% of rating at max junction temperature.
Protection Circuits: Implement hardware-based overcurrent (shunt + comparator), overtemperature (NTC thermistor), and overvoltage (TVS diodes at inputs) protection for all critical paths.
Redundancy: For safety-critical isolation switches (VBL185R05), consider using two devices in series for redundancy or a mechanical contactor in parallel.
IV. Scheme Core Value and Optimization Suggestions
(A) Core Value
Optimized Power-to-Weight Ratio: The combination of high-efficiency IGBT for propulsion and ultra-compact MOSFETs for distribution minimizes total system weight and thermal management overhead, directly extending range.
Inherent Safety & Robustness: The selected devices provide the voltage ruggedness and package reliability needed for ASIL-D directed systems, forming a foundation for functional safety certification.
Scalability and Integration Path: The chosen package portfolio (TO247, DFN8, TO263) allows for straightforward scaling (paralleling) and future migration to integrated power modules (IPMs) or SiC solutions as technology matures.
(B) Optimization Suggestions
Higher Power Propulsion: For power levels >100kW, consider paralleling VBP16I60 devices or evaluating Silicon Carbide (SiC) MOSFETs like VBGQTA1101 (100V/415A, SGT) for low-voltage high-current applications or future 800V+ systems with corresponding SiC devices.
Enhanced Integration: For space-constrained avionics bays, replace multiple VBQD3222U with multi-channel load switch ICs or use VBA3108N (Dual-N, SOP8) for slightly higher voltage (100V) requirements.
Extreme Environment: For operation in very low temperatures, select variants with lower Vth guarantees. For highest vibration environments, consider packages with superior solder joint reliability or add mechanical stiffening.
Intelligent Power Switching: Pair the VBQD3222U with a microcontroller featuring advanced power management peripherals to implement sophisticated, state-based load control and health monitoring.
Conclusion
The strategic selection of IGBTs and MOSFETs is pivotal to achieving the unprecedented blend of high power density, operational safety, and reliability required for certified AI personal flying cars. This scenario-driven scheme provides a practical, device-level foundation for developing compliant and competitive powertrain and power distribution systems. Continuous evaluation of Wide Bandgap (SiC/GaN) semiconductors and intelligent power modules will be key to achieving the next leaps in efficiency and integration, powering the future of urban aerial transportation.

Detailed Topology Diagrams