AS3824 controller enables independent, flexible PWM control of each
of 16 LED channels for local dimming and true reproduction of the
darkest shades of black
ams AG (SIX: AMS), a leading provider of high performance sensors and
analog ICs, today introduced the AS3824, a 16-channel LED TV backlight
controller which performs local dimming of sections of a display screen
to provide both improved picture quality and valuable power savings of
up to 20-30%.
The new backlight controller is intended for use in the latest
high-definition (HD) and ultra high-definition (UHD, or ‘4K’)
televisions, as well as high dynamic range (HDR) monitors and displays.
The AS3824 includes a fully flexible 12-bit PWM generator for each of
its 16 channels, to enable sections of a display screen to be dimmed
independently. Each PWM generator may be synchronized with an external
synchronization signal.
The 16-channel independent dimming capability means that the backlight
intensity of each section can be precisely controlled to match the
picture content of each successive frame on display. When a section of
the frame needs to be dark, the LEDs illuminating just that section may
be dimmed independently of the rest, enabling a TV to reproduce
faithfully even the blackest of blacks, and enhancing the perceived
picture quality. By contrast, conventional global backlight controllers
cannot prevent some light from leaking into sections of the display
screen that should be black, thus reproducing black as grey.
The local dimming enabled by the AS3824 also provides for additional
system power savings compared to global backlight controllers.
The AS3824 backlight controller features a precise internal 10-bit DAC,
which provides accurate (±0.5%) global control of the current through
external MOSFETs or bipolar transistors. It supports all LED backlight
topologies, with no limit on the current through or voltage across the
LEDs.
The device also includes a supplementary 8-bit current-control DAC for
each of the 16 channels, which can be used to boost or lower the current
locally through the LEDs in certain frames, thereby increasing dynamic
contrast ratios. This enables the AS3824 to support HDR monitors and HDR
TVs.
The AS3824 is backed by a comprehensive set of protection functions,
including thermal shutdown when the temperature exceeds 140°C, and open
and short LED detection. The device may be programmed via a serial
peripheral interface and daisy-chained to as many AS3824 devices as are
needed in the application.
‘With the introduction of the AS3824, ams is the first semiconductor
manufacturer to provide an LED backlighting controller that is ready to
support the latest Dolby Vision™ standard for UHD displays, enabling
display manufacturers to achieve a stunning contrast between light and
dark and the deepest black rendition’, said Bernd Krafthoefer, Marketing
Manager for Power Management business line at ams.
The AS3824 is available for sampling now. Unit pricing is $1.25 in order
quantities of 1,000.
A demonstration kit for the AS3824 is available on request. For sample
requests and for more technical information, please go to www.ams.com/LED-backlight-controller/AS3824.
Download press picture and block diagram at http://www.ams.com/eng/Press/Press-Releases/
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