TLC5951 Datasheet, PDF (30/46 Pages) Texas Instruments – 24-Channel, 12-Bit PWM LED Driver with 7-Bit Dot Correction and 3-Group, 8-Bit Global Brightness Control

TLC5951
SBVS127B – MARCH 2009 – REVISED DECEMBER 2009
www.ti.com
Table 3 and Table 4 show how the DC data affect the percentage of the maximum current each output. See
Figure 46 for the DC data latch configuration. Figure 11 illustrates the timing diagram for writing data from the GS
data path into the shift registers and latches. Figure 12 illustrates the timing diagram for writing data from the DC
data path into the shift registers and DC latches. DC data are automatically latched from the DC/BC/FC/UD shift
register into the DC data latch with an internal latch signal. The internal latch signal is generated in 3 ms to 7 ms
after the last DCSCK rising edge.
When the IC powers on, the DC data latch contains random data. Therefore, DC data must be written into the
TLC5951 and latched into the DC data latch before turning on the constant-current outputs. XBLNK should be
low when powering on the TLC5951 to force all outputs off until the internal registers can be programmed. All
constant-current outputs are forced off when XBLNK is low. The data bit assignment is shown in Table 9.
BITS
6-0
13-7
20-14
27-21
34-28
41-35
48-42
55-49
62-56
69-63
76-70
83-77
Table 9. Dot Correction Data Bit Assignment
DATA
OUTR0
OUTG0
OUTB0
OUTR1
OUTG1
OUTB1
OUTR2
OUTG2
OUTB2
OUTR3
OUTG3
OUTB3
BITS
90-84
97-91
104-98
111-105
118-112
125-119
132-126
139-133
146-140
153-147
160-154
167-161
DATA
OUTR4
OUTG4
OUTB4
OUTR5
OUTG5
OUTB5
OUTR6
OUTG6
OUTB6
OUTR7
OUTG7
OUTB7
Global Brightness Control Data Latch
The global brightness control (BC) data latch is 24 bits long. The BC data latch consists of bits 168-191 in the
DC/BC/FC/UD data latch.
The data of the BC data latch are used to adjust the constant-current values for eight channel constant-current
drivers of each color group. The current can be adjusted from 0% to 100% of each output current adjusted by
brightness control with 8-bit resolution. Table 5 describes the percentage of the maximum current for each
brightness control data.
When the IC is powered on, the data in the BC data latch are not set to a specific default value. Therefore,
brightness control data must be written to the BC latch before turning on the constant-current output. The data bit
assignment is shown in Table 10.
BITS
175-168
183-176
191-184
Table 10. Data Bit Assignment
GLOBAL BRIGHTNESS CONTROL DATA BITS 7-0
OUTR0-OUTR7 group
OUTG0-OUTG7 group
OUTB0-OUTB7 group
30
Submit Documentation Feedback
Product Folder Link(s): TLC5951
Copyright © 2009, Texas Instruments Incorporated