Preliminary
4 Channels Constant Current LED Driver With
Protocol and Differential Interface
MY9943
MY-Semi
General Description
Single-line Addressing DMX512
Features
The MY9943, 4 channels constant current LED driver with ✦ White / CW.WW / R.G.B / R.G.B.W applications
14bits grayscale APDM (Adaptive Pulse Density Modulation)
control, supports standard DMX512 protocol and fully
differential interface suited for long distance parallel
applications. The distinctive DMX512 decoding approach
could decode precisely a standard DMX512 signal. And each
device loads one/two/three/four grayscale data according to
two slot selection pins and a single-line addressing path. The
differential interface provides wide common-mode range to
support long distance transmission without common-ground
power systems.
✦ One / Two / Three / Four slots data selection for different
LED configuration applications
✦ 7V to 40V Operating supply voltage
✦ 350mA maximum constant current output (Per channel)
✦ Current setting by 4 external resistors
✦ 40V Rated output channels for long LED strings
✦ ±1.5% (typ.) LED Current accuracy between channels
✦ ±3% (typ.) LED Current accuracy between chips
✦ Standard DMX512 protocol decoder (USITT DMX512-A)
The device operates over 7V to 40V input voltage
range and provides 4 open-drain constant current sinking
outputs that are rated to 4 0 V and delivers up to 350mA
of high accuracy current to each string of LED. The current at
each output is programmable by means of four external
current setting resistors. The MY9943 provides the gamma
correction, gamma value is 2.2, to transform 8bits DMX data
to 14bits APDM data in order to enhance brightness contract.
The 14bits adaptive pulse density modulation makes sure
that the frame refresh rate is higher than 2KHz. And an
accurate oscillator is built in for free running APDM grayscale
control and DMX512 decoder.
[Patent]
[Patent]
✦ Distinctive single-line addressing approach [Patent]
✦ Wide common-mode range for differential input signals
✦ Gamma, 2.2, to transform 8bits DMX to 14bits APDM data
✦ 14bits grayscale resolution with Adaptive Pulse Density
Modulation
✦ Frame refresh rate > 2000Hz as a LED driver
Frame refresh rate > 120Hz as a PWM generator
✦ Traditional non-scramble constant current waveform for
high power LED applications (PWM generator only)
✦ Built-in oscillator for grayscale control and DMX512
decoder
Furthermore, MY9943 could drive High Power LED directly
by shorting the output channels and changing the slot data
number. The POL function makes MY9943 as a PWM
generator to support driving high power LEDs. MY9943 is
available in SSOP24/TSSOP20 packages and specified over
the -40°C to +85°C ambient temperature range.
✦ -40°C to +85°C Ambient temperature range
Applications
Order information
PART
PIN PACKAGE
❑ Standard DMX512 protocol system
❑ Full Color Mesh Display
MY9943SS SSOP24-150mil-0.635mm 2500 pcs/Reel
MY9943TE TSSOP20-173mil-0.65mm 2500 pcs/Reel
❑ Architectural and Decorative Lighting
Typical Operating Circuits
Pin Configuration
Nov. 2011 Ver. 0.5
MY-Semi Inc.
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For pricing, delivery, and ordering information, pleases contact MY-Semi Inc. at +886-3-560-1668,
or email to INFO@MY-Semi.com.tw or visit MY-Semi’s website at www.MY-Semi.com.tw
