Car window/sunroof design based on relay MLX81150

The motors for windows and sunroofs are bidirectional, and the motors rotate in different directions by changing the direction of the current input to the armature winding. Each window and sunroof has a motor, which is a type of motor that is not directly grounded. All electric windows have two sets of control devices as shown in Figure 1. One set is the main switch, which can be used by the driver to control the lifting and lowering of the four windows; the other set is the sub-switch, which is installed in the middle of each window, and can be controlled by the passengers to lift the window next to them. The main switch and the sub-switch do not interfere with each other and can be controlled independently. The sunroof is remotely controlled by the driver operating the switch.

Car windows and sunroofs are perfect applications for the LIN bus, especially when the driver controls the lifting and lowering of four windows through the master control switch. When the driver operates the window switch, the central ECU unit sends a command to the corresponding MXL81150 through the LIN bus. When the MXL81150 receives the command, it controls the motor to start and realize the lifting (closing) and lowering (opening) of the window or sunroof.

The MLX81150 has two independent, fully integrated relay drivers that can be used to drive relays to control DC motors, manipulating the forward and reverse rotation of the motors to raise (close) or lower (open) the windows and sunroof, as shown in Figure 3.

The MLX81150 has four power FET gate drivers that can be used to drive a full-bridge controlled DC motor and manipulate the forward and reverse rotation of the motor to raise (close) or lower (open) the windows and sunroof, as shown in Figure 4.

MXL81150 main features:

It integrates a high-performance 16-bit embedded flash microcontroller with 32K bytes of flash memory capacity to meet the requirements of some specific motor control applications, and the built-in 4-bit central processor can fully handle the LIN protocol;

Many external components critical to motor control are integrated into a small package, which reduces chip peripheral circuits, PCB design, bill of materials cost and system power consumption;

With a LIN communication interface, it receives commands through LIN to control the start/stop of the motor, so that the raising (closing) and lowering (opening) of the windows/sunroof can be controlled by remote communication;

With two relay drivers and four power FET gate drivers, you can choose to drive relays or full-bridge control motors, and achieve motor speed regulation through PWM;

With an interface for connecting a Hall sensor, which determines the position of the window/sunroof;

With current detection interface, anti-pinch function is realized by detecting the running current of the motor;

The internal EEPROM is used to store the position parameters of the windows and sunroof;

The working current in sleep mode is only 30uA;

Normal operating voltage range 5.5V-18V, chip operating voltage as low as 3.9V; 28V start condition, 45V overvoltage protection;

Temperature range is -40℃ - 150℃;

Detailed information: MXL81150: Controller with MCU, PWM and LAN transceiver