5.8 Auxiliary Supplies
The Auxiliary power supplies are needed for operation of the PSFB-CDR.
Insert high-level block diagram for auxiliary supply
- The +12V supply is a SEPIC power
stage. This topology has a series capacitance between input and output stages,
thereby providing short-circuit protection from the battery in case of a system
Fault. This becomes important when the 12V LV battery is permanently connected to
the DC-DC converter. +12V rail is used to power the following systems:
- High-Voltage Isolated Gate driver supply input
- Low-Voltage Side non-Isolated Gate driver supply
- MRV300 is a drop-in Buck
converter SMT module which generates +5V from +12V and provides power to the
following components:
- Low-voltage side of Isolated Gate drivers
- CAN-FD communication
- Digital signal microcontroller plug-in card power supply
- SEPIC and Gate driver push-pull PMIC supply
- +3V3 rail for general system ICs (OP-AMPs, Optocoupler) and sensors.
- Isolated +20V/-5V High-Voltage
Gate driver supply. This subcircuit has the following power rails:
- Leg-1 HSS +20V/-5V.
- Leg-2 HSS +20V/-5V.
- Common Leg-1 & Leg-2 LSS +20V/-5V; Additionally, +5V_MCU_EXT is produced from LSS +20V for Isolated High-Voltage VIN sense subcircuit.