Similar to other multifunction body applications, the power seat system utilizes 48V to power the multiple high-power DC motors responsible for seat adjustments. Each motor has a either a dedicated full-bridge driver or shared half-bridge drivers for controlling the movement based on user input from the seat control switches. Similar to the door module, the higher-current motors are the first to transition to 48V, with the low-current actuators remaining on a 12V supply for the time being. Motors driving intermittent functions such as position adjustment typically use brushed motors, while functions that run more continuously, such as seat fans, typically use brushless motors.

Figure 2-4 shows an implementation that drives high-current motors directly from the 48V supply, while lower-current loads remain as 12V loads, requiring a step-down regulator to produce a 12V supply.

Figure 2-4 Example 48V Seat Module Block Diagram