TLC5970 Datasheet, PDF (21/48 Pages) Texas Instruments – 3-Channel, 12-Bit, PWM LED Driver with Buck DC/DC Converter and Differential Signal Interface

TLC5970
www.ti.com
SBVS140 – MARCH 2010
Equation 2 determines each output (OUTn) sink current:
I_OUTn (mA) = I_OLCMax (mA) ´
DCn
127d
´
BC
127d
Where:
I_OLCMax = the maximum channel current for each channel determined by R_IREFn
DCn = the decimal dot correction value for each OUTn in the DC latch (DCn = 0d to 127d)
BC = the decimal brightness control value in the brightness control latch (BC = 0d to 127d)
(2)
DC, BC, and function current control data are shown in Table 2, Table 3, and Table 4, respectively.
DC DATA
(Binary)
000 0000
000 0001
000 0010
—
111 1101
111 1110
111 1111
Table 2. DC Data versus Current Ratio and Set Current Value
DC DATA
(Decimal)
0
1
2
—
125
126
127
DC DATA
(Hex)
00
01
02
—
7D
7E
7F
BC DATA
(Hex)
7F
7F
7F
—
7F
7F
7F
SET CURRENT
RATIO TO
MAXIMUM
CURRENT (%)
0
0.8
1.6
—
98.4
99.2
100.0
150 mA I_OLCMax
(mA, Typical)
0
1.18
2.36
—
147.64
148.82
150.00
10 mA I_OLCMax
(mA, Typical)
0
0.08
0.16
—
9.84
9.92
10.00
BC DATA
(Binary)
000 0000
000 0001
000 0010
—
111 1101
111 1110
111 1111
Table 3. BC Data versus Current Ratio and Set Current Value
BC DATA
(Decimal)
0
1
2
—
125
126
127
BC DATA
(Hex)
00
01
02
—
7D
7E
7F
DC DATA
(Hex)
7F
7F
7F
—
7F
7F
7F
SET CURRENT
RATIO TO
MAXIMUM
CURRENT (%)
0
0.8
1.6
—
98.4
99.2
100.0
150 mA I_OLCMax
(mA, Typical)
0
1.18
2.36
—
147.64
148.82
150.00
10 mA I_OLCMax
(mA, Typical)
0
0.08
0.16
—
9.84
9.92
10.00
BC DATA
(Hex)
00
01
02
—
7D
7E
7F
Table 4. DC and BC Data versus Current Ratio and Set Current Value
DC DATA
(Hex)
00
01
02
—
7D
7E
7F
SET CURRENT RATIO
TO MAXIMUM CURRENT
(%)
0
0
0.01
—
96.88
98.43
100.0
150 mA I_OLCMax
(mA, Typical)
0
0.01
0.04
—
145.31
147.65
150.00
10 mA I_OLCMax
(mA, Typical)
0
0
0
—
9.69
9.84
10.00
Copyright © 2010, Texas Instruments Incorporated
Product Folder Link(s): TLC5970
Submit Documentation Feedback
21