ROHM’s new 4ch/6ch LED drivers for LCD backlights

In recent years, the continuing evolution of ADAS (Advanced Driver Assistance Systems) and enhanced car infotainment functionality have led to the use of larger displays. Consequently, LED drivers for LCD backlights in automotive displays are required to provide high efficiency drive that improves rated output current while reducing power consumption. On top, as flickering of automotive displays can lead to poor visibility and unsafe conditions, LED drivers must be capable to avoid this symptom.

Conventional LED drivers consume relatively large amounts of power and are susceptible to flickering during PWM dimming. In contrast, ROHM has developed LED drivers for LCD backlights that combine proprietary low power technology with seamless PWM dimming. This eliminates flickering when changing display brightness from low to high.

These new products leverage proprietary low power consumption technology to reduce losses in LED driver current control circuits. The result is 20% lower overall IC power consumption compared to conventional products under typical conditions (80mA/ch LED circuit current, 12V power supply). This contributes to lower power consumption in medium- to large-sized automotive displays where power consumption is an issue.

At the same time, all models are equipped with both DC and PWM dimming to meet a wide range of requirements. As there no longer exists a need to switch current feedback mode for low/high brightness change with ROHM’s original seamless PWM dimming technology, flickering that occurs with general PWM dimming is reduced, improving system reliability.

Going forward, ROHM will continue to contribute to the evolution of next-generation mobility by developing products that leverage its strengths in analogue technology to promote the advancement and lower power consumption in future automotive cockpit functions. (Fig. 2 + 3)

Reference Designs with PCB Design data, SPICE models and EMC reports available.

Applications

• Instrument clusters

• Car infotainment

• Head-up displays (HUDs)

• Electronic mirrors (side/rear view)

Product lineup

All new model’s products are equipped with both DC and PWM dimming for broad applicability. ROHM’s seamless PWM dimming enables smooth, flicker-free dimming from low to high brightness. (Fig. 4)