TLC5929 Datasheet, PDF (16/36 Pages) Texas Instruments – 16-Channel, Constant-Current LED Driver with 7-Bit Global Brightness Control, Power-Save Mode

TLC5929
SBVS159 – APRIL 2011
www.ti.com
GLOBAL BRIGHTNESS CONTROL (BC) FUNCTION
The TLC5929 has the ability to adjust the output current of all constant current outputs simultaneously. This
function is called global brightness control (BC). The global BC for all outputs (OUT0 to OUT15) can be set with
a 7-bit word. The global BC adjusts all output currents in 128 steps from 0% to 100%. where 100% corresponds
to the maximum output current set by R_IREF. Equation 2 calculates the actual output current. BC data can be set
via the serial interface.
I_OLCn (mA) =
I_OLCMax (mA) ´ BC
127
Where:
I_OLCMax = the maximum constant-current value for each output determined by R_IREF.
BC = the global brightness control value in the control data latch (0h to 7Fh)
(2)
Table 2 shows the BC data versus the constant-current ratio against I_OLCMAx.
BINARY
000 0000
000 0001
000 0010
∙∙∙
111 1101
111 1110
111 1111
Table 2. BC Data versus Constant-Current Ratio Against I_OLCMAx
BC DATA
DECIMAL
0
HEX
00
RATIO OF OUTPUT
CURRENT TO I_OLCMax
(%)
0
I_OLC
(mA, I_OLCMax= 40mA, typ)
0
I_OLC
(mA, I_OLCMax= 1mA, typ)
0
1
01
0.8
0.31
0.01
2
02
1.6
0.63
0.02
∙∙∙
∙∙∙
∙∙∙
∙∙∙
∙∙∙
125
7D
98.4
39.4
0.98
126
7E
99.2
39.7
0.99
127
7F
100.0
40.0
1.00
16
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