TLC5944 Datasheet, PDF (16/34 Pages) Texas Instruments – 16-Channel, 12-Bit PWM LED Driver with 6-Bit Dot Correction and Pre-Charge FET

TLC5944
SBVS112 – JUNE 2008 ...................................................................................................................................................................................................... www.ti.com
Dot Correction (DC) Function
The TLC5944 is able to individually adjust the output current of each channel (OUT0 to OUT15). This function is
called dot correction (DC). The DC function allows users to individually adjust the brightness and color deviations
of LEDs connected to the outputs OUT0 to OUT15. Each respective channel output current can be adjusted in
64 steps from 0% to 100% of the maximum output current, I_OLCMax. Dot correction data are entered into the
TLC5944 via the serial interface.
Equation 2 determines the sink current for each output (OUTn):
DCn
I_OUTn (mA) = I_OLCMax (mA) ´ _63d
(2)
Where:
• I_OLCMax = the maximum channel current for each channel determined by R_IREF
• DCn = the programmed dot correction value for OUTn (DCn = 0 to 63d)
When the IC is powered on, the data in the dot correction shift register and data latch are not set to any default
values. Therefore, DC data must be written to the DC latch before turning on the constant current output.
Table 2 summarizes the DC data versus current ratio and set current value.
DC DATA
(Binary)
00 0000
00 0001
00 0010
... ...
11 1101
11 1110
11 1111
Table 2. DC Data versus Current Ratio and Set Current Value
DC DATA
(Decimal)
0
1
2
... ...
61
62
63
DC DATA
(Hex)
00
01
02
... ...
3D
3E
3F
SET CURRENT
RATIO TO
MAX CURRENT (%)
0.0
1.6
3.2
... ...
96.8
98.4
100.0
OUTPUT CURRENT
(mA, Typical)
AT I_OLCMax = 60 mA
0.0
0.4
0.8
... ...
58.1
59.0
60.0
OUTPUT CURRENT
(mA, Typical)
AT I_OLCMax = 2 mA
0.000
0.032
0.064
... ...
1.937
1.968
2.000
16
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