6.6 kW on-board electric vehicle charger
Solution advantages and features:
● 3CH interleaved PFC for high efficiency and power density. Also reduces current ripple
● Full-bridge LLC improves efficiency by using high bus voltage
● Hardware PFC and LLC control methods, easy to design and less faulty
● Full-featured solution including input/output current/voltage sensing and CC/CV PWM control interface
● Bus voltage is adjustable to optimize efficiency according to output voltage
● Adopt SiC MOSFETs and diodes to improve efficiency
PFC controller FAN9673
● Continuous conduction mode with average current mode control
● Three-channel interleaving operation
● Programmable operating frequency range: 18 kHz~40 kHz or 55 kHz~75 kHz
● Programmable PFC output voltage
● Two current limit functions
● TriFault Detect prevents feedback loop failures
● SAG protection
● Programmable soft start
● Undervoltage lockout (UVLO)
● Differential current sensing
● LLC resonant converter secondary side PFM controller with synchronous rectifier control
● Charging current control for better transient response and simple feedback loop design
•Adaptive synchronous rectification control with dual edge tracking
● Closed loop soft start for monotonic rising output
● Wide operating frequency (39 kHz~690 kHz)
● Green features that improve light load efficiency
● Symmetrical PWM control at light load to limit switching frequency to reduce switching losses
● Protection function (with automatic restart)
♦ Over current protection (OCP)
♦ Output short circuit protection (OSP)
♦ Non-zero voltage switching protection (NZS) compensation reduction (frequency shift)
♦ Power limit compensation reduction (frequency shift)
● Overheating protection (OTP)
● Programmable dead time for primary side switch, secondary side synchronous rectifier
● VDD Undervoltage Lockout (UVLO)
● Wide operating temperature range -40°C to +125°C
● Automotive certification
▶Display board photo
▶Solution block diagram
Core technology advantages
We adopt a single full-bridge LLC topology for high efficiency and reasonable cost. It consists of U60 and Q60, Q62, Q70, Q72, etc. The NCV4390 (U60) is a current mode advanced LLC controller. It is a pin-to-pin compatible device with the FAN7688. If you can't find the device on the website, you can refer to the instructions for FAN7688. For more details on this part, see the datasheet and application notes. Due to the high output voltage (250−450 Vdc), synchronous rectifiers do not contribute much to the rectifier conduction losses. Therefore, we omit the SR function of NCV4390. The NCV57000 is a high-current single-channel IGBT driver with internal galvanic isolation. It is used to drive SiC MOS in the LLC stage, and the NCL30059 is used to provide high-reliability power supply to the high-side driver.
NVHL020N090SC1 NVHL060N090SC1 High reliability SiC MOS process, smaller parasitic parameters and smaller Q and tr, provide high reliability for SiC applications.
Project specifications
● input Voltage: 90 − 264 Vac
● Output Power: 6.6 kW
● Topology: 3CH Interleave PFC+Full Bridge LLC
● I/O Isolation: yes
● Output Voltage: 250 − 450 Vdc
● Ripple: 5%
● Max Current: 16A
● Min Current: 0A
● PFC (Yes/No): yes
● Typical Efficiency: 94%
● Inrush Limiting: 48A
● Operating Temp.: −20 − 85°C
● Dimension: 254 x 198 x 70 mm + Heatsink