Design Win

Trunk Control Advanced Solution with L99DZ200G and ToF

Solution Description

This solution describes a hands-free gesture recognition system designed to open a car trunk using an L99DZ200G door zone systems IC with current sensing for safety, an SPC58 automotive microcontroller and FlightSense™ sensors for reliable foot movement identification.

In addition to offering increased convenience, as drivers can open the trunk without having to take their keys out of their pocket or purse, hands-free gesture recognition solutions promote hygiene by eliminating the need for physical contact with door handles. By implementing this type of sleek, appealing feature, car manufacturers can offer a more advanced and user-friendly experience to their customers.

With many car owners frustrated by the unpredictable behavior of their lift gates in many recent car models offering a similar application, our smart solution describes a simplified way for people to open or close their trunk using a predefined foot movement. It also includes a safety feature based on current sensing that prevents damage if there are obstacles when opening or closing the trunk.

ST's hands-free power liftgate solution only uses three components for a reduced bill of materials and a simpler design phase. FlightSense™ sensors located below the bumper are used to detect the foot movement under the trunk. Once the foot movement is detected, a general-purpose SPC58 C Line automotive microcontroller (SPC58EC80E5) will confirm the correct pattern and send a command to open or close the trunk to the single automotive-grade door zone systems IC (L99DZ200G) that is able to synchronously drive the two motors required to raise and lower the car tailgate as well as a third motor to lock the trunk. In addition to being able to supply two external LED modules for additional driver or passenger safety, the L99DZ200G includes a Generator mode that allows its H-bridge drivers to autonomously switch on all the external low-side MOSFETs when an overvoltage is detected.

Of course, to further ensure security, the hands-free solution only works if the vehicle is already unlocked and parked.

  • All Features

    • Technical   
      • Supply voltage: 12  V
      • Sensor supply voltage: 3.3 V
      • Digital logic supply voltage: 5 V
      • Synchronous driving of trunk motors
      • FOTA capability for application software
    • Perfromance
      • Maximum current for each motor: 35 A
      • Foot movement pattern response time: 1 s
    • Certification
      • Automotive-grade 32-bit microcontroller and door zone IC
      • Application code is MISRA C 2012 compliant