help with WS2811
Moderators: adafruit_support_bill, adafruit

help with WS2811

by ozeri on Mon Nov 28, 2011 3:01 am

Hello all,

I recently bought LED strips that has 2811 IC.
I had no idea 2811 is so different from 2801 as it has no clock wire.
can someone help me with Arduino coding for that ?
As all samples online are for the 2801 and use both Data and clock lines, the 2811 seems to have only data line.
I have no idea how to get started with that.
I have the PDF datasheet but cannot upload it here.

Thanks,

Dror

cannot upload the pdf so here is a copy :

WS2811
Signal line 256 Gray level 3 channal
Constant current LED drive IC
http://www.world-semi.com
Feature
l Output port compression 12V.
l Built in stabilivolt, Only add a resistance to IC
VDD feet when under 24V power supply.
l Gray level 256 can be adjusted and scan freque
ncy not less than 400Hz/s.
l Built in signal reshaping circuit,after wave reshaping
to the next driver, ensure wave-form distortion
not accumulate.
l Built-in electric reset circuit and power lost reset
circuit.
l Cascading port transmission signal by single line.
l Any two point the distance more than 10m transmission
signal without any increasecircuit.
l When the refresh rate is 30fps, low speedmodelc
ascade number are not less than 512 points, high
speed mode not less than1024 points.
l Send data at speeds of up to 400 Kbps and 800
Kbps two patterns.
Applications
l LED decorative lighting.
l Indoor/outdoor LED video or irregular screen.
General description
The WS2811 is 3 output channels special for LED driver circuit. It internal include intelligent digital port
data latch and signal reshaping amplification drive circuit.Also include a precision internal oscillator and a 12V
voltage programmable constant current output drive. In the purpose of reduce power supply ripple, the 3 output
channels designed to delay turn-on function.
IC use single NZR communication mode.After the chip power-on reset, the DIN port receivedata from con
troller, the first IC collect initial 24bit data then sent to the internal data latch, theother data which reshaping
by the internal signal reshaping amplification circuit sent to the next cascade IC through the DO port. After
transmission for each chip,the signal to reduce 24bit. IC adopt auto reshaping transmit technology, making the
chip cascade number is not limited the signal transmission, only depend on the speed of signal transmission.
The data latch of IC depend on the received 24bit data produce different duty ratio signal at OUTR,
OUTG, OUTB port. All chip synchronous send the received data to each segment when the DIN port input a
reset signal. It will receive new data again After the reset signal finished. Before a new reset signal received,
the control signal of OUTR ,OUTG, OUTB port unchanged. IC sent PWM data that received justly to OUTR,
OUTG, OUTB port, after receive a low voltage reset signal the time retain over 50us. We offer two package
SOP8 and DIP8.
WS2811
Signal line 256 Gray level 3 channal
Constant current LED drive IC
http://www.world-semi.com
PIN configuration
PIN function
NO. Symbol Function description
1 OUTR Output of Red PWM control
2 OUTG Output of Green PWM control
3 OUTB Output of Blue PWM control
4 GND Ground
5 DOUT Data signal cascade output
6 DIN Data signal input
7 SET
Set work mode of IC as low speed model(connect VDD)
or high speed model(vacant)
8 VDD Power supply voltage
Absolute Maximum Ratings
Prameter Symbol Ratings Unit
Power supply voltage VDD +6.0~+7.0 V
Output voltage VOUT 12 V
Input voltage VI -0.5~VDD+0.5 V
Operation junction
temperature
Topt -25~+85 ℃
Storage temperature range Tstg -55~+150 ℃
Note: If the voltage on the pins exceeds the maximum ratings may cause permanent damage to the
device.
WS2811
Signal line 256 Gray level 3 channal
Constant current LED drive IC
http://www.world-semi.com
Electrical Characteristics(TA=-20~+70℃,VDD=4.5~5.5V,VSS=0V,unless otherwise specified)
Prameter Smybol conditions Min Tpy Max Unit
Low voltage
output current
IOL ROUT —— 18.5 —— mA
Idout Vo=0.4V,DOUT 10 —— —— mA
Input current II VI=VDD/VSS —— —— ±1 μA
Input voltage level
VIH DIN,SET 0.7VDD —— —— V
VIL DIN,SET —— —— 0.3 VDD V
Hysteresis voltage VH DIN,SET —— 0.35 —— V
Switching characteristics(TA=-20~+70℃,VDD=4.5~5.5V,VSS=0V,unless otherwise specified)
Prameter Symbol Condition Min Tpy Max Unit
Operation
frequency
Fosc1 —— —— 400 —— KHz
Fosc2 —— —— 800 —— KHz
Transmission
delay time tPLZ
CL=15pF,DIN→
DOUT,RL=10KΩ —— —— 300 ns
Fall time tTHZ
CL=300pF,OUTR/
OUTG/OUTB —— —— 120 μs
Data transmission
rate
FMAX Duty ratio50% 400 —— —— Kbps
Input capcity CI —— —— —— 15 pF
Low Speed mode time
T0H 0 code,high voltage time 0.5 μs ±150ns
T1H 1 code,high voltage time 1.2 μs ±150ns
T0L 0 code,low voltage time 2.0 μs ±150ns
T1L 1 code,low voltage time 1.3 μs ±150ns
RES low voltage time Above 50μs
Note: It is one half of the time when high speed mode(reset time unchanged)
WS2811
Signal line 256 Gray level 3 channal
Constant current LED drive IC
http://www.world-semi.com
Sequence chart:
0 code
1 code
RET code
T0H
T0L
T1H
T1L
Treset
Cascade method:
DIN DO DIN DO DIN DO
IC 1 IC 2 IC 3
D1 D2 D3 D4
Data transmission method:
Note: The data of D1 is send by MCU,and D2, D3, D4 through IC internal reshaping amplification to
transmit.
Composition of 24bit data:
R7 R6 R5 R4 R3 R2 R1 R0 G7 G6 G5 G4 G3 G2 G1 G0 B7 B6 B5 B4 B3 B2 B1 B0
Note: Follow the order of RGB to sent data and the high bit sent at first.
Data refresh cycle 1 Data refresh cycle 2
first 24bit
second
24bit third 24bit first 24bit second
24bit third 24bit
second
24bit third 24bit second
24bit third 24bit
third 24bit third 24bit
D1
D2
D3
D4
reset code
>=50us reset
code
WS2811
Signal line 256 Gray level 3 channal
Constant current LED drive IC
http://www.world-semi.com
Typical application circuit:
1.power supply is 5V with 1 LED and constant current (18.5mA) driving
B G R
100R
104
33R
5V
33R
B G R
100R
104
33R
5V
VCC
LED
controller
DAT
GND
VDD OUTB OUTG OUTR
DIN
GND
DO
GND
WS2811
VDD OUTB OUTG OUTR
DI N
GND
DO
GND
WS2811
depend on controller
33R
Fig 1
This driving mode use constant current output, the advantage of is the LED can retain luminance and
colour temperature when the power supply lessen. We require, in order to prevent power spikes phenomenon
and power reverse polarity, series a not more than 100ohm resistor at the po-wer supply pin(VDD). The capacitance
104 as bypass capacitor. To prevent the reflection and hot-swap protection, we suggest to connect a 33
ohm resistor at the data input or output port for impedance.
2.power supply is 12V with 3 LED and constant current(18.5mA) driving
B
B
B G
G
G R
R
R
104
33R 33R
B
B
B G
G
G R
R
R
104
33R
12V 12V
VDD OUTB OUTG OUTR
DIN
GND
DO
GND
WS2811
VDD OUTB OUTG OUTR
DIN
GND
DO
GND
WS2811
VCC
LED
controller
DAT
GND
R1 R1
RR RR
33R
depend on controller
Fig 2
The same as the front mode, it is also use constant current output. In this circuit, R1 is used as the IC
internal LDO divider resistance and the value is 3.8K. The capacitance 104 as bypass capacitor. To prevent the
reflection and hot-swap protection, we suggest to connect a 33ohm resistor at the data input or output port for
impedance. At the OUTR port we should add a divider resistance RR. The value of RR can be derived by
the following equation:
18.5
RR = 12 - 3VLEDR KΩ
VLEDR is the red LED forward conduction voltage drop.
WS2811
Signal line 256 Gray level 3 channal
Constant current LED drive IC
http://www.world-semi.com
3.power supply 12V with 3 LED and constant voltage driving
B G R
104
12V
33R
B G R
B G R
33R
B G R
104
12V
33R
B G R
B G R
VDD OUTB OUTG OUTR
DIN
GND
DO
GND
WS2811
VDD OUTB OUTG OUTR
DIN
GND
DO
GND
WS2811
VCC
LED
controller
DAT
GND
R1
RL RL RL
RB RG RR
R1
RL RL RL
RB RG RR
33R
depend on controller
Fig 3
Applying the outside-enlarged transistor mode, the highest voltage value of VCC depends on the NPN transistor's
VCEO, generally 25V above. The current of each channel is set by resistance RR/RG/RB, computation
formula is as follows:
RR
V V V
R
I CC-3 LEDR- CE
=
In above formula, IR is the current of output end OUTR, RR is the value of red voltage-dividing resistor,
VCC as the power supply voltage of LED(here is 12V), VLEDR is the red LED forward conduction voltage
drop, VCE as the saturated pipe pressure drop of transistor. Likewise, the current of OUTG and OUTB can
be set.
Select 5KΩ as value of base resistance RL, magnification of NPN transistor β>150, connect circuit according
to the method of Fig 3, the luminance data of MCU sends is opposite to actual luminance.
R1 is LDO voltage-dividing resistor inside IC (R1=3.3KΩ), the capacitance 104 as bypass capacitors, input
end and output end of IC are connected a resistance 33ohm in series respectively to provide hot-swap protection
and resistance matching.
WS2811
Signal line 256 Gray level 3 channal
Constant current LED drive IC
http://www.world-semi.com
4.power supply 12V with 6 LED and constant voltage driving
B G R
104
24V
33R
RL RL RL
B G R
33R
VDD OUTB OUTG OUTR
DI N
GND
DO
GND
WS2811
VCC
LED
control ler
DAT
GND
R1
RB RG RR
104
33R 33R
VDD OUTB OUTG OUTR
DIN
GND
DO
GND
WS2811
B G R
24V
RL RL RL
B G R
R1
RB RG RR
depend on controller
Applying the outside-enlarged transistor mode, the highest voltage value of VCC depends on the NPN transistor's
VCEO, generally 25V above. The current of each channel is set by resistance RR/RG/RB, computation
formula is as follows:
RR
V V V
R
I CC-6 LEDR- CE
=
In above formula, IR is the current of output end OUTR, RR is the value of red voltage-dividing resistor,
VCC as the power supply voltage of LED(here is 24V), VLEDR is the red LED forward conduction voltage
drop, VCE as the saturated pipe pressure drop of transistor. Likewise, the current of OUTG and OUTB can
be set.
Select 5KΩ as value of base resistance RL, magnification of NPN transistor β>150, connect circuit according
to the method of Fig 3, the luminance data of MCU sends is opposite to actual luminance.
R1 is LDO voltage-dividing resistor inside IC (R1=8.1KΩ), the capacitance 104 as bypass capacitors, input
end and output end of IC are connected a resistance 33ohm in series respectively to provide hot-swap protection
and resistance matching.
WS2811
Signal line 256 Gray level 3 channal
Constant current LED drive IC
http://www.world-semi.com
Package imformation:
DIP-8 Package:
Symbo
l
Dimensions In Millmeters Dimensions In Inches
Min Nom Max Min Nom Max
A — — 4.31 — — 0.170
A1 0.38 — — 0.015 — —
A2 3.15 3.40 3.65 0.124 0.134 0.144
B 0.38 0.46 0.51 0.015 0.018 0.020
B1 1.27 1.52 1.77 0.050 0.060 0.070
C 0.20 0.25 0.30 0.008 0.010 0.012
D 8.95 9.20 9.45 0.352 0.362 0.372
E 6.15 6.45 6.65 0.242 0.252 0.262
E1 — 7.62 — — 0.300 —
e — 2.54 — — 0.1 —
L 3.00 3.30 3.60 0.118 0.130 0.142
θ 0º — 15º 0º — 15º
WS2811
Signal line 256 Gray level 3 channal
Constant current LED drive IC
http://www.world-semi.com
SOP-8 Package:
Symbol
Dimensions In Millmeters Dimensions In Inches
Min Max Min Max
A 1.350 1.750 0.053 0.069
A1 0.100 0.250 0.004 0.010
A2 1.350 1.550 0.053 0.061
b 0.330 0.510 0.013 0.020
c 0.170 0.250 0.006 0.010
D 4.700 5.100 0.185 0.200
E 3.800 4.000 0.150 0.157
E1 5.800 6.200 0.228 0.244
e 1.270 0.050
L 0.400 1.270 0.016 0.050
θ 0º 8º 0º 8º
ozeri
 
Posts: 1
Joined: Mon Nov 28, 2011 2:50 am

Re: help with WS2811

by adafruit_support_bill on Mon Nov 28, 2011 6:26 am

Hi,

We don't sell or support any WS2811 based strips. You should contact the seller for assistance.
User avatar
adafruit_support_bill
 
Posts: 29119
Joined: Sat Feb 07, 2009 9:11 am

Re: help with WS2811

by ivar on Mon Jan 28, 2013 7:47 pm

For using the WS2811 led strip with the arduino check out https://code.google.com/p/fastspi/
ivar
 
Posts: 1
Joined: Mon Jan 28, 2013 7:45 pm