TLC5943_17 Datasheet, PDF (26/40 Pages) Texas Instruments – 16-Channel, 16-Bit PWM LED Driver with 7-Bit Global Brightness Control

TLC5943
SBVS101 – DECEMBER 2007
www.ti.com
Status Information Data (SID)
Status information data (SID) are 17-bit, read-only data. Both the LED open detection (LOD) error and the
thermal error flag (TEF) are shifted out onto the SOUT pin with each rising edge of the shift clock, SCLK. The 16
LOD bits for each channel and the TEF bit are written into the 17 most significant bits of the Grayscale Shift
Register at the rising edge of the first SCLK after XLAT goes low. As a result, the previous data in the 17 most
significant bits are lost at the same time. No data are loaded into the other 175 bits. Figure 30 shows the bit
assignments. Figure 13 illustrates the read timing for the status information data.
Status Information Data (SID) Configuration
MSB
16
OUT15
LOD Data
LOD Data of OUT15 to OUT0
15
¼
2
OUT14
OUT1
¼
LOD Data
LOD Data
1
OUT0
LOD Data
TEF (1 Bit)
LSB
0
TEF Data
SOUT
¼
The 16 LOD bits for each channel and the TEF bit overwrite
the most significant 17 bits of the Grayscale Shift Register at the
rising edge of the first SCLK after XLAT goes low.
GS Data for OUT15
GS Data for OUT14-OUT1
GS Data for OUT0
MSB
LSB
255
254
241
240
239
16
15
0
OUT15-Bit15 OUT15-Bit1
OUT15-Bit1 OUT15-Bit0 OUT14-Bit15
¼ _{(LOD-OUT15) (LOD-OUT14)}
(LOD-OUT1) (LOD-OUT0) (TEF)
¼ _{OUT1-Bit0 OUT0-Bit15}
¼
OUT0-Bit0
SIN
SCLK
(BCSEL = low)
Grayscale Shift Register (16 Bits 16 Channels)
´
Figure 30. Status Information Data Configuration
The LOD data update at the rising edge of the 33rd GSCLK pulse after BLANK goes low; the LOD data are
retained until the next 33rd GSCLK. LOD data are only checked for outputs that are turned on during the rising
edge of the 33rd GSCLK pulse. A '1' in an LOD bit indicates an open LED or short LED to GND condition for the
corresponding channel. A '0' indicates normal operation. LOD shows a '0' even if the LED is open or shorted to
GND when the grayscale data are less than 1000h (4096d). Therefore, grayscale data must be greater than
1001h (4097d) to correctly receive LOD data.
The TEF bit indicates that the IC temperature is too high. The flag also indicates that the IC has turned off all
drivers to avoid damage by overheating the device. A '1' in the TEF bit means that the IC temperature has
exceeded the detect temperature threshold (T_(TEF)) and the driver is turned off. A '0' in the TEF bit indicates
normal operating temperature conditions. The IC automatically turns the drivers back on when the IC
temperature decreases to less than T_(TEF) –T_(HYS). When the IC powers on, LOD data do not show correct values.
Therefore, LOD data must be read from the 33rd GSCLK pulse input after BLANK goes low. Table 6 shows a
truth table for both LOD and TEF.
SID DATA
0
1
Table 6. LOD and TEF Truth Table
CONDITION
LED OPEN DETECTION (LODn)
THERMAL ERROR FLAG (TEF)
LED is connected (V_OUTn > V_LOD)
LED is open or shorted to GND (V_OUTn ≤ V_LOD)
Device temperature is low (temp ≤ T_(TEF) –T_(HYS))
Device temperature is high (temp > T_(TEF))
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