TLC5923_16 Datasheet, PDF (11/28 Pages) Texas Instruments – 16-CHANNEL LED DRIVER WITH DOT CORRECTION

TLC5923
www.ti.com
SLVS550B – DECEMBER 2004 – REVISED JANUARY 2013
Error Information Output
The open-drain output XERR is used to report both of the TLC5923 error flags, TEF and LOD. During normal
operating conditions, the internal transistor connected to the XERR pin is turned off. The voltage on XERR is
pulled up to V_CC through a external pullup resistor. If TEF or LOD is detected, the internal transistor is turned on,
and XERR is pulled to GND. Since XERR is an open-drain output, multiple ICs can be OR'ed together and pulled
up to V_CC with a single pullup resistor. This reduces the number of signals needed to report a system error.
To differentiate LOD and TEF signal from XERR pin, LOD can be masked out with BLANK = HIGH.
Table 3. XERR Truth Table
TEMPERATURE
T_J < T_(TEF)
T_J > T_(TEF)
T_J < T_(TEF)
T_J > T_(TEF)
CONDITION
BLANK
H
L
OUTn VOLTAGE
Don't Care
OUTn > V_(LOD)
OUTn < V_(LOD)
OUTn > V_(LOD)
OUTn < V_(LOD)
(1) Note: High-Z indicates high impedance
ERROR INFORMATION
TEF
LODn
L
L
H
L
L
H
H
L
H
XERR
High-Z ⁽¹⁾
L
High-Z
L
L
L
TEF: Thermal Error Flag
The TLC5923 provides a temperature error flag (TEF) circuit to indicate an overtemperature condition of the IC. If
the junction temperature exceeds the threshold temperature T_(TEF) (160°C typical), TEF becomes H and XERR
pin goes to low level. When the junction temperature becomes lower than the threshold temperature, TEF
becomes L and XERR pin becomes high impedance.
LOD: LED-Open Detection
The TLC5923 has an LED-open detector to detect broken or disconnected LEDs, which should be connected to
the output. The LED-open detector pulls the XERR pin down to GND when the LED open is detected. An open
LED is detected when the following three conditions are met:
1. BLANK is low
2. On/Off data is high
3. The voltage of OUTn is less than 0.3 V (typical)
The LOD status of each output can also be read out from the SOUT pin. Figure 10 shows the LOD data format.
Table 4 shows the LOD truth table.
MSB
15
LOD
OUT15
LOD
OUT14
LOD
OUT13
LOD
OUT2
LOD
OUT1
LSB
0
LOD
OUT0
LOD Data
Figure 10. LOD Data Format
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