The MY9942, 4 channels constant current LED driver with 14bits grayscale APDM (Adaptive Pulse Density Modulation) control, supports standard / 4X 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 nine address setting pins (512 addresses). The differential interface provides wide common-mode range to support long distance transmission without common-ground power systems.
The device operates over 7V to 40V input voltage range and provides 4 open-drain constant current sinking outputs that are rated to 40V 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 MY9942 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.
Furthermore, MY9942 could drive High Power LED directly by shorting the output channels and changing the slot data number. The POL function makes MY9942 as a PWM generator to support driving high power LEDs. MY9942 is available in 28-pin SSOP/TSSOP packages and specified over the -40°C to +85°C ambient temperature range.
Standard DMX512 protocol system
Full Color Mesh Display
Architectural and Decorative Lighting
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)
4X DMX512 protocol selection (Baud rate=1MHz)
Wide common-mode range for differential input signals
Gamma,2.2, to transform 8bits DMX to 14bits APDM data
14bits gray-scale 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)
512 addresses set by 9 external pins
Build-in oscillator for grayscale control and DMX512 decoder
-40°C to +85°C Ambient temperature range