Date: 16th May 2011
LED Driver IC for automotive head lamps
and DRLs
ROHM CO., LTD., has developed the BD8381EFV-M single-chip
LED driver for use with automotive LED headlamps and daytime
running lights (DRLs). BD8381EFV-M incorporates PWM function
for use with DRLs. ROHM began shipping samples of the new
product in April (sample pricing: ¥400/part) and plans
to begin mass production with an initial monthly volume
of 50,000 parts in July 2011. The company plans to split
production into a pre-process handled by ROHM Wako Co.,
Ltd., (Okayama Prefecture) and a post-process handled by
ROHM Integrated Systems (Thailand) Co., Ltd., (Thailand).
Automakers have been gradually switching to LED lighting
for automotive headlamps, and LED-based headlamps are expected
to eventually account for most of the market due to the
higher efficiency and longer service life promised by the
technology. Increasingly, manufacturers are equipping their
vehicles with LED-driven DRLs to ensure an optimal level
of safety and visibility, and LED headlamps and DRLs are
widely expected to become a fixture of automotive equipment
specifications. At the current time, use of LED headlamps
is limited to certain portions of the market such as the
luxury segment, and automakers and headlamp manufacturers
have used general-purpose LED driver LSIs or designs based
on discrete components, necessitating the inclusion of a
separate driver circuit when equipping the vehicle with
DRLs. ROHM said it launched an early effort to develop a
dedicated LSI for use with LED headlamps based on its forecast
of the future adoption of this technology, leading to the
development of an LSI incorporating all the functionality
needed to serve as an LED driver that would be used with
headlamps. The BD8381EFV-M provides PWM light modulation
without a microcontroller by incorporating a built-in oscillator
circuit for use with DRLs, which are beginning to enter
into widespread use particularly in Europe and the United
States, where automakers are pioneering their use. The part
also offers a range of protective functionality to detect
headlamp faults such as LED short and open states to better
meet the automotive market's need for a high level of reliability.
An absolute maximum voltage of 50 V gives the product sufficient
dielectric strength to withstand battery voltage fluctuations.
Principal features of the BD8381EFV-M LED driver LSI for
automotive headlamps:
1. Input voltage range of 5 V to 30 V
2. Built-in step-up/step-down current mode DC/DC controller
3. Built-in CR timer for PWM light modulation
4. Support for PWM and linear light modulation
5. Built-in protective functions (UVLO, OVP, TSD, OCP, SCP,
LED open detection, LED short detection)
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