TLC5955 Datasheet, PDF (36/53 Pages) Texas Instruments – TLC5955 48-Channel, 16-Bit, PWM LED Driver with DC, BC, LED Open-Short Detection, and Internal Current Setting

TLC5955
SBVS237 – MARCH 2014
www.ti.com
8.4.4.5 Auto Data Refresh Function
This function delays updating the grayscale (GS) and dot correction (DC) data until the end of one entire display
period. If both DC data and GS data are written by the end of an entire display period, the input DC data are held
in the control data latch and the GS data are held in the common shift register. Both DC and GS data are copied
to the 336-bit DC data latch and 768-bit GS data latch at the end of an entire display period. The data latches
are used for the next display period. GS data are directly copied from the common shift register to the GS data
latch. Therefore, GS data must be written after the DC data are written. Furthermore, the GS data in the common
shift resistor must not be changed until all data are copied to the GS data latch. Figure 31 and Figure 32 show
timing diagrams for this function.
Control Data Write (MSB of the Common Shift Register = 1)
SIN
DCR0 DCR0 DCR0 DCR0
4A
3A
2A
1A
764 765 766 767 768
SCLK
DCR0
0A
769
LAT
GSCLK
DSPRPT Bit
in Control Data
(Internal)
TMGRST Bit
in Control Data
(Internal)
RFRESH Bit
in Control Data
(Internal)
Common Shift
Register
(Internal)
GS Counter
Data (Internal)
Internal LAT
Enable
(Internal)
Internal
LAT Signal
(Internal)
GS Data
Latch
(Internal)
Control Data
Latch
(Internal)
DC Data
Latch
(Internal)
OFF
OUTn
ON
DSPRPT bit=1
TMGRST bit=0
RFRESH bit=1
GS counter data is incremented
at each GSCLK rising edge.
Old Control Data
Grayscale Data Wriet (MSB of the Common Shift Register = 0)
L
GSB15 GSB15
15A 14A
12
3
GSR0 GSR0 GSR0
3A
2A
1A
766 767 768
GSR0
0A
769
Grayscale Data Write
L GSB15
15B
1
2
65535th GSCLK
65536th GSCLK
1
3
5
7
2
4
6
8
New Control Data
The internal LAT enable is set
to high level when LAT is input
for GS data writing.
The internal LAT signal is generated
at 65536^th GSCLK when Internal LAT
enable is high level only.
Old Grayscale Data
SID are loaded at 1st
GSCLK input.
0
GS counter data is incremented
at each GSCLK rising edge.
The internal LAT enable
is set to low level when
1st GSCLK is input.
New Grayscale Data
Old DC Data
OUTn are controlled by old GS/DC data.
New DC Data
OUTn are controlled
by new GS/DC data.
SOUT
H
DCR0 DCR0 DCR0
2A
1A
0A
L
LOD LOD
B15A G15A
Figure 31. Auto Data Refresh Function 1 (DSPRPT = 1, TMGRST = 0, and RFRESH = 1)
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