In this typical example, a central electronic control unit (ECU) communicates with the door module via the vehicle CAN bus, providing commands for functions like locking, unlocking, and window control. A 48V power supply is used to drive the window lift motor due to its relatively high current. The other functions in the door can remain as 12V actuators, due to the lower current and the cost of redesigning the existing 12V mechanisms. In that case, a 48V-to-12V step-down (buck) regulator is needed to supply 12V to the low-current loads.

Figure 2-1 Example 48V Door Module Block Diagram

The CAN system basis chip (SBC) is robust to faults up to ±58V on the bus lines, in case the 48V supply is bundled in the same wire harness. The buck converter supplies up to 10A of current at 12V to the multifunction driver, which controls all the lower-power door functions. For the higher-power window lift motor which is powered by the 48V, the half-bridge drivers allow up to 70V on the supply. The ideal diode controller prevents damage due to reverse-voltage faults on the 48V supply line. Coordinating all the communications and functions of the door module is the microcontroller, in this case a 160MHz Arm® Cortex®-M33 MCU with CAN-FD connectivity and enhanced security features preferred for door applications.