Rohm Semiconductor: Mini LED Driver ICs for Automotive Displays

Rohm Semiconductor (Rohm) recently unveiled new electronic components designed specifically for the automotive industry. The latest addition to their product lineup is a series of large LCD backlight Mini LED driver ICs.

Unlike traditional driver ICs commonly used in similar applications, Rohm's next-generation Mini LED driver ICs, known as the BD94130xxx-M series, feature an innovative design. These ICs utilize a matrix configuration with up to eight sets of switches (8-line Switch Controller) combined with a 24-frequency constant current controller. This design allows a single chip to control up to 192 individual sections of the Mini LED backlight, significantly surpassing the partition count achievable with direct drive designs. The increased number of controlled sections offers the advantage of reducing the overall number of driver ICs required for the entire Mini LED LCD display, thereby streamlining the manufacturing process.

In the automotive industry, integrated display panels have evolved from small navigation systems and 4-6-inch screens to larger, comprehensive panels that replace traditional instrument clusters. Some manufacturers even showcase concept models with display panels exceeding 30 inches in size. As the display area grows, the partition count in the Mini LED backlight panel also increases substantially.

For instance, Rohm presents a 10-inch automotive Mini LED LCD display that incorporates a backlight panel divided into 576 partitions. The conventional approach using direct drive ICs with a 48-frequency constant current controller necessitates the use of 12 chips, consuming a significant circuit board area of over 1,200 square millimeters. In contrast, Rohm's BD94130xxx-M series requires only three chips, occupying a mere 200 square millimeters of the circuit board, which is just 16% of the previous solution. This reduction in size not only helps to minimize the thickness and dimensions of the circuit board but also contributes to more efficient product designs.

Addressing a common concern with Mini LEDs, the BD94130xxx-M series provides the flexibility to configure the number of switch sets (4, 6, or 8) based on specific requirements. This feature allows for adjustments in power consumption and heat generation. Additionally, by reducing the number of driver ICs needed for the Mini LED backlight panel of the same size, the series offers a more flexible and time-efficient option for product designers.

While OLED displays have gained popularity due to their design flexibility and suitability for curved surfaces, automotive displays face unique challenges. They must endure a wide range of environmental conditions, from pitch-black nights to intense sunlight, from heavy snowfall to scorching heat. As a result, automotive displays have stricter requirements for heat resistance, display contrast, power consumption, and lifespan compared to consumer electronics.

Mini LED LCDs provide a compelling alternative to traditional LCD displays. These advanced displays offer improved display contrast and power efficiency by adjusting the brightness or even turning off specific sections (partitions) of the backlight. Moreover, Mini LED LCDs boast advantages such as low power consumption and minimal heat dissipation when compared to OLED displays.