Automotive hi-res display chipsets promote functional safety

January 11, 2017 // By Graham Prophet
Rohm and Lapis Semiconductor have added chipsets designed to drive and control automotive LCDs, including larger high resolution monitors used for navigation and the instrument cluster. The expanded lineup is compatible with functional safety measures for speedometers, side mirrors, and other vehicle systems.

LCD use in vehicles for the instrument cluster, navigation, electronic mirrors, and other systems, with larger, higher resolution displays, calls for an increase in the number of driver and controller channels. This makes system configuration and operation verification more difficult, favouring chipset solutions. In applications such as electronic mirrors, malfunctions can lead to serious accidents and functional safety is required.

 

Rohm’s chipsets integrate a gamma correction IC, timing controller (T-CON), source driver, and gate driver for driving HD/FHD class displays (the highest resolution currently on the market), along with a power management IC (PMIC) to ensure optimum drive operation. Each IC is designed to share information as needed, achieving automotive-grade reliability and claiming a first for functional safety in devices for displays. Compatibility with LCDs for side mirrors and speedometers is incorporated. An integrated failure detection function in the timing controller verifies operation, making it possible to configure high resolution LCD panels.

 

Each IC configured in the chipset integrates a function for mutually selecting the expected failure mode. It is possible to detect panel failure and confirm and provide feedback on information such as input signals to the LCD as well as peeling/destruction of the LCD driver. For example, the driver may not notice that the screen for the side mirrors has frozen: the functional safety features can detect if the screen is frozen. The power management IC includes a double register for detecting abnormalities and auto-refresh function to enable recovery during abnormal operation, ensuring high reliability against unexpected influences such as noise. The timing controller is equipped with a Fail detection circuit for verifying chipset operation. And the setting of each output in the power management IC can be changed by simply rewriting the internal register value. This reduces development resources while contributing to common board designs.

 

Rohm Semiconductor; www.rohm.com