TLC5940-EP Datasheet, PDF (18/33 Pages) Texas Instruments – 16-CHANNEL LED DRIVER WITH DOT CORRECTION AND GRAYSCALE PWM CONTROL

TLC5940-EP
SLVSA51D – MARCH 2010 – REVISED MAY 2010
www.ti.com
Figure 15 shows the dot correction data packet format which consists of 6 bits x 16 channel, total 96 bits. The
format is Big-Endian format. This means that the MSB is transmitted first, followed by the MSB-1, etc. The DC
15.5 in Figure 15 stands for the 5^th most significant bit for output 15.
MSB
95
90
89
DC 15.5
DC 15.0 DC 14.5
DC OUT15
DC OUT14 − DC OUT2
6
5
LSB
0
DC 1.0 DC 0.5
DC 0.0
DC OUT0
Figure 15. Dot Correction Data Packet Format
When VPRG is set to VCC, the TLC5940 enters the dot correction data input mode. The length of input shift
register becomes 96 bits. After all serial data are shifted in, the TLC5940 writes the data in the input shift register
to DC register when XLAT is high, and holds the data in the DC register when XLAT is low. The DC register is a
level triggered latch of XLAT signal. Since XLAT is a level-triggered signal, SCLK and SIN must not be changed
while XLAT is high. After XLAT goes low, data in the DC register is latched and does not change. BLANK signal
does not need to be high to latch in new data. XLAT has setup time (tsu1) and hold time (th1) to SCLK as shown
in Figure 16.
V_CC
VPRG
DC Mode Data
Input Cycle n
DC Mode Data
Input Cycle n+1
SIN
DC n−1
LSB
DC n
MSB
DC n
MSB−1
DC n
MSB−2
DC n
LSB+1
DC n
LSB
DC n+1
MSB
DC n+1
MSB−1
SCLK
SOUT
t_wh0
1
2
3
DC n−1
MSB
DC n−1
MSB−1
t_wl0
DC n−1
MSB−2
XLAT
95
96
DC n−1 DC n−1
LSB+1
LSB
t_su1
DC n
MSB
t_wh2
t_h1
1
2
DC n
DC n
MSB−1 MSB−2
Figure 16. Dot Correction Data Input Timing Chart
The TLC5940 also has an EEPROM to store dot correction data. To store data from the dot correction register to
EEPROM, DCPRG is set to high after applying V_PRG to the VPRG pin. Figure 17 shows the EEPROM
programming timings. The EEPROM has a default value of all 1s.
18
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