TLC5930 Datasheet, PDF (32/39 Pages) Texas Instruments – 12-CHANNEL LED DRIVER

TLC5930
SLLS528 – MARCH 2002
PRINCIPLES OF OPERATION
calculating constant-current output
The current value of constant-current output can be calculated using the following expression.
ǒ Ǔ _{IOLC (n) + 42 IDC (n) ) ICC (n)}
(2)
Where I_DC is main current (except color tone correction), I_CC is color tone correction current. Both currents are
referenced with reference current, I_(IREF), and I_(DC) is established by dot correction data and gray scale data.
I_CC from color tone correction data and color tone correction control data. n is output terminal number, 0 to 11.
reference current
The reference current I_IREF can be calculated with external resistor, R_IREF, voltage reference, V_IREF, and plane
brightness data, r_BC, using the following expression.
ǒ Ǔ I_IREF + 4
VȀ_IREF
R_IREF
(3)
ǒ Ǔ _ȧȱȲ ^ȳȴȧ VȀ_IREF + 0.4 )
0.6 ^ǒr_BC ) 1^Ǔ
64
V_IREF
(4)
main current
The main current, I_DC, can be calculated with dot correction data, r_DC, logic signal, S_MAIN, established by gray
scale data, and reference current, I_IREF, using the following expression.
ǒ Ǔ _{IDC (n) +}
r_{DC (n)}
256
S_{MAIN (n)}
I_IREF
(5)
Where S_MAIN, is set to following value depending on gray scale data, r_GC.
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{ ^{SMAIN (n) =}
1: r_{GC (n )} > 0
0: r_{GC (n )} = 0
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