Close
0%
0%

Digital LED display-APA107/APA102/WS2812B/SK6812

we used APA107 LED chip to make this kinds led display, now nobody can provide APA102/APA102C

Similar projects worth following
APA107 will be upgraded again, the PWM can be 26-28kHz, faster and cheaper than APA102.

we used APA107 LED chip to make this kinds led display, of course you can adopt apa102/apa102c/sk9822, but apa102/apa102c have already stopped production, and sk9822 go too slow, so APA107 LED is the best choice at this moment, more stable and faster than sk9822 LED.

I received many spam emails from china, they used SK9822 LED to impersonate APA107.
If you want APA107 LED, please only buy it from NEWSTAR.

APA107 RGB LED is a type ic for the three-color RGB Diming control strip and
string ,This ic using the CMOS process to provide three-color RGB LED output
driver to adjust the output with 256 gray scale and 32 brightness adjustment ,APA
with 2 signal output way , one is clock ,another is data, the clock and data is
synchronizated ,so that the crystal cascade piece of output movement is
sychronizated. (Replace APA102/APA102C, better than sk9822)

Data protocol using unipolar NRZ communication mode, the pixel is reset after the end of DIN, accept the data transmitted from the controller to the 24bit, the first to send data by the first pixel to pixel extraction, internal data latch, the remaining data after the internal plastic the processing circuit after shaping amplification through the DO port output began to turn to the next cascade of pixels, each pixel through a transmission signal, reduce. Pixel using automatic shaping forwarding technology, makes the number of cascade without signal

transmission limit of the pixel, only limited signal transmission speed.



The LED has a low driving voltage, environmental protection and energy saving, high brightness, scattering angle, good consistency, low power, long life and so on. The control circuit is integrated in the LED above, more simple circuit, small volume, easy installation.



Main Application Field:
● Full color LED string light, LED full color module, LED super hard and soft lights, LED guardrail tube, LED appearance / scene lighting
● LED point light, LED pixel screen, LED shaped screen, a variety of electronic products, electrical equipment etc..



Description:
● Top SMD internal integrated high quality external control line serial cascade constant current IC;
● control circuit and the RGB chip in SMD 5050 components, to form a complete control of pixel, color mixing uniformity and consistency;
●built-in data shaping circuit, a pixel signal is received after wave shaping and output waveform distortion will not guarantee a line;
●The built-in power on reset and reset circuit, the power does not work;
●gray level adjusting circuit (256 level gray scale adjustable);
● red drive special treatment, color balance;
● line data transmission;
● plastic forward strengthening technology, the transmission distance between two points over 10M;
●data transmission frequency up to 800Kbps, when the refresh rate of 30 frames per second, a cascade of not less than 1024;
● built-in powerpolarity protection module, powerpolarity will not damage.



Mechanical Product Size (unit mm):

Mechanical Size and Pin Map (unit mm):

Pin Function:

The electrical parameters (limit parameters, Ta=25 C, VSS=0V):

The electrical parameters (such as no special instructions, TA=-

20 ~ +70 ~ 5.5V C, VDD=4.5, VSS=0V):

The dynamic parameters (Ta=25 C):

RGB chip characteristic parameters:

The data transmission time (TH+TL=1.25μs±600ns):

Timing waveform:

The method of data transmission:

Note: the D1 sends data for MCU, D2, D3, D4 for data forwarding

automatic shaping cascade circuit.


The data structure of 24bit:

Note: high starting, in order to send data (G7 - G6 - ...... ..B0)

The typical application circuit:

Compare with APA102C SK9822, the advantage of APA107,

1, Intelligent reverse connect protection, the power supply reverse connection does not damage the IC.

2, The control circuit and the LED share the only power source.

3, Control circuit and RGB chip are integrated in a package of 5050 components, form a complete control of pixel point.

4, Built-in signal reshaping circuit, after wave reshaping to the next driver, ensure wave-form distortion not accumulate.

5, Built-in electric reset circuit and power lost reset circuit.

6, Each pixel of the three primary color can achieve 256 brightness display, completed 16777216 color full color display, and scan frequency not less than 400Hz/s.

7, Cascading port transmission signal by single line.

8, Any two point the distance more than 5m transmission signal without any increase circuit.

9, When the refresh rate is 30fps, cascade number are not less than1024 points.

10, Send data at speeds of 800Kbps.

11,The color of the light were highly consistent, cost-effective..

Applications

12, Full-color module, Full color soft lights a lamp strip.

13, LED decorative lighting, Indoor/outdoor...

Read more »

APA107 White.pdf

APA107 White datasheet

Adobe Portable Document Format - 3.81 MB - 08/20/2018 at 06:29

Preview
Download

APA107 RGB.pdf

APA107 RGB datasheet

application/pdf - 2.79 MB - 06/02/2018 at 03:13

Preview
Download

apa102.pdf

APA102 datasheet

Adobe Portable Document Format - 957.52 kB - 06/02/2018 at 02:13

Preview
Download

5050 SK9822 LED Chip.pdf

SK9822 datasheet

Adobe Portable Document Format - 841.30 kB - 06/02/2018 at 02:13

Preview
Download

sk6812_datasheet.pdf

sk6812 datasheet

Adobe Portable Document Format - 571.02 kB - 04/19/2017 at 07:19

Preview
Download

  • 1 × APA107 RGB LED

  • 1
    SK9822 Compare with APA102

    Firstly Let us analyze the APA102, although it was more expensive than the common WS2812, and harder to come by, it had some intriguing properties. The main benefits are a timing-insensitive  SPI interface, allowing easy interfacing to standard periphery, and a much higher PWM frequency of >19kHz, making the APA102 almost flicker free.

    So much about that. Considering how things with LEDs from China go, it should not take too long for clones to appear? Indeed! Recently, several comments showed up on my blog, reporting about issues with APA102 LEDs they bought. It quickly turned out that these were SK9822, APA102 clones from the same company that already brought the SK6812 to us, a WS2812 clone.

    At a first glance, it is obvious that both LEDs use different ICs. The die used in the SK9822 is much smaller than the APA102. As a rough estimate, the APA102 seems to be 1 mm², while the SK9822 is ~0.65 mm². The smaller die likely results in a lower cost. So it is not surprising that vendors are trying to replace APA102 with SK9822…

    But why are people complaining about the SK9822 being incompatible? According to the datasheet (linked here), the data format is supposed to be exactly the same. In fact, it looks like the sections in the datasheet are copied directly from the APA102 datasheet. However, even the original APA102 datasheet wasn’t too accurate when it came to the data format. For more details, please check out my post on investigating the APA102.

    Probing the SK9822 quickly revealed that something was off when using it in the same way as a APA102. As shown above, the data format itself seems to be identical, and data forwarding from one LED to the next seems to work in the same way as with the APA102. However, every colour combination written to the SK9822, only was shown during the next update cycle. Some more probing isolated the issue: The SK9822 updates the PWM registers in the first cycle after the next start frame (0x00000000), while the APA102 updates the PWM register immediately after receiving the data. Since the next start frame is sent at the beginning of the next update, this means that the color update is delayed.

    I can only speculate about the reason for this deviation. Possibly the SK9822 was implemented using the APA102 datasheet as a reference, and this was a misinterpretation on the, admittedly, not very accurate description of the protocol. Actually, the way the update is implemented in the SK9822 makes more sense than in the APA102, because it allows to update all LEDs at once instead of the staggered update of the APA102.

    Unified protocol

    The only way to get the SK9822 to work properly is to send an additional “reset frame” of 32 zero bits at the end of the bitstream to trigger the PWM register update. Luckily there is a very easy way to implement this in a way where it is compatible to the APA102: The endframe of the APA102 can be either ones or zeroes (see here). Simply emitting another 32 zeroes at the end will not have any impact on the APA102, given that also the endframe is changed to zeros.

    A protocol that is compatible to both the SK9822 and the APA102 consists of the following:

    A start frame of 32 zero bits (<0x00> <0x00> <0x00> <0x00> )
    A 32 bit LED frame for each LED in the string (<0xE0+brightness> <blue> <green> <red>)
    A SK9822 reset frame of 32 zero bits (<0x00> <0x00> <0x00> <0x00> ).
    An end frame consisting of at least (n/2) bits of 0, where n is the number of LEDs in the string.
    SK9822 LED driver characteristics

    To probe the SK9822 LED driver, I mounted a photodiode in front of one LED and connected it to an oscilloscope. This allowed me to directly monitor the modulation scheme of the LEDs. The exemplary image below shows both the dataline and the photodiode signal during an update from RGB=0xFF0000 to RGB=0x800000. The PWM frequency can be directly measured in the scope trace. It is 4.7kHz for the SK9822 – about four times lower than the 19.2kHz, but not even close to the 430 Hz flicker hell of the WS2812.

    Something interesting happened, when I tried to change the global brightness setting. In the trace below I started with maximum brightness and reduced it to 50% by either using the global brightness register or the PWM register. As can be seen below, reducing the brightness to 50% reduces the light output from the LED, but no pulse width modulation is visible. It appears that the SK9822 uses a controlled current source to set the global brightness. This is in contrast to the APA102, which superimposed a lower frequency PWM pattern if the global brightness was not set to its maximum.

    This is confirmed by the trace below. Here, I activated the PWM by setting RGB=0x800000 and ramping through the global brightness setting. The global brightness setting does indeed control the driver current setting.

    The implementation of a programmable current source in the SK9822 is actually a very welcome improvement. In contrast to the original, the APA102, the LEDs do not start to flicker if the global brightness is reduced. This is a very nice feature if the SK9822 is used in a display. In addition, lowering the current setting allows to reduce peak current consumption, which can be quite an issue if you have plenty of LEDs PWMed at 3x20mA.

    Summary

    At a first glance, the SK9822 looks like an identical clone of the APA102, but taking a closer look reveals plenty of differences, see table below.

    In conclusion, the SK9822 is not an exact clone of the APA102. It adds some interesting features. For example the programmable current source to control global brightness and a non-staggered update. But there are also some drawbacks like the protocol incompatibility and the lower PWM frequency. The incompatibility in the protocol can be worked around by using the unified protocol proposed above.

View all instructions

Enjoy this project?

Share

Discussions

Steve Michel wrote 08/29/2018 at 10:09 point

We NEWSTAR will upgrade our own APA107 to reach 26-28kHz PMW, and better price…good supplier......APA107 will help many client save budget

  Are you sure? yes | no

Steve Michel wrote 06/02/2018 at 02:24 point

APA102C has stopped producing...As Taiwan APA102 supplier didn't provide IC any more, but Taiwan APA102 is super expensive...now APA107 is the best choice to replace APA102/APA102C, as it is the upgrade of APA102, IC and LED all made in China.

  Are you sure? yes | no

Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates