This reference design is an automotive electric vehicle capacitor pre-charger power solution. The design is powered from the 12 V battery to charge a 4 mF capacitor bank to 400 V in 2 seconds. The design uses an isolated flyback controller operating at a switching frequency of 100 kHz. The initial output voltage is set for 60 V. A primary-side referenced control line is used to set the output to its final value of 400 V. Once the pre-charge sequence is complete, the UVLO function may be used to turn off the controller while the capacitor bank is connected to the rest of the system.
Features
- Isolated charging of large capacitor bank
- Replaces large relay and limiting resistor
- Tested with up to 1 meter wiring to the load capacitors
- Primary side control for output voltage setting
- Compact power stage and controller layout for small solution size