In recent years, the advancement of ADAS (Advanced Driver Assistance Systems), along with the expansion of in-vehicle infotainment functionality, has led to the adoption of higher-resolution displays in vehicles to improve visibility. LED drivers with a local dimming function, capable of switching off backlighting only in dark areas of the LCD screen, improve display performance and reduce power consumption. Automakers developing next-generation cockpits are already aware of these advantages. However, since the number of zones controlled by conventional direct-type LED drivers on a single integrated circuit is less than 100, the number of LED drivers and peripheral components will also increase as automotive displays become larger and have more zones. This presents a significant design challenge.

To address this need, ROHM has developed products capable of controlling more zones than conventional integrated circuits, thus reducing the mounting area by decreasing the number of LED drivers required. The BD94130xxx-M series of matrix LED drivers combines an 8-line switching driver with a 24-channel current driver, enabling the control (dimming) of up to 192 miniLED backlight zones with a single integrated circuit. Furthermore, the miniLEDs in each zone can be adjusted independently using a local dimming function, contributing to higher contrast ratios and reduced energy consumption for displays.

For example, with today's conventional 10-inch infotainment screens, which have around 600 zones, ROHM's new products allow for working with only a quarter of the number of LED drivers compared to existing products (48 zones), reducing the mounting area for the LED drivers by approximately 84%. And this advantage will only increase as screens get larger and the number of zones in next-generation cabins increases.

New products: BD94130xxx-M
ROHM's BD94130xxx-M series of matrix LED drivers combines a 24-channel current driver with a switching driver that can be divided into 8 lines (max.). The number of switching driver lines can be selected from 3 patterns (4, 6, or 8) via the register configuration, supporting a wide variety of specifications based on the number of zones and the current consumption of the LEDs.

In addition, a built-in feedback control function maintains a constant feedback voltage independent of the LED temperature characteristics, reducing working hours for thermal design and loss rate.

Applications:
ROHM's new products are equipped with local dimming capabilities to support a wide variety of high-contrast automotive displays.
• Electronic rearview mirrors (side/rear)
• In-vehicle infotainment
• Instrument clusters
• Head-up displays (HUDs)

More information