TLC5929 Datasheet, PDF (29/36 Pages) Texas Instruments – 16-Channel, Constant-Current LED Driver with 7-Bit Global Brightness Control, Power-Save Mode

TLC5929
www.ti.com
SBVS159 – APRIL 2011
THERMAL SHUTDOWN (TSD) AND THERMAL ERROR FLAG (TEF)
The thermal shutdown (TSD) function turns off all constant-current outputs when the junction temperature (T_J)
exceeds the threshold (T_TEF = +165°C, typ) and sets all LOD data bits to '1'. When the junction temperature
drops below (T_TEF – T_HYST), the output control starts normally. The TEF remains '1' until the next rising edge on
LAT even if the temperature drops below the low level. Figure 31 shows the timing diagram and Table 13 shows
the truth table for TEF.
SCLK
LAT
Common Shift
Register Bits[15:0]
(Internal)
Common Shift
Register Bit 16
(Internal)
Output On/Off
Data (Internal)
These data are copied to the on/off data latch at LAT rising edge.
Previous On/Off Data
LOD/TEF Data
‘0’
New Latched GS Data
SIDLD Data _{‘01’ (LOD is selected)}
(Internal)
BLANK ^Low
OUTn
OFF
All outputs are forced off
by TSD function.
ON
OFF
Resumed with T_J
going down.
ON
High
OFF
ON
OFF
Device Junction
Temperature (T_J)
PTW in SID
(Internal Data)
TEF in SID
(Internal Data)
T_J < T_PTW
T_J ³ T_PTW
‘1’
T_J ³ T_TEF
T_J < T_TEF - T_HYST
PTW is not reset at LAT rising edge because SIDLD
does not select LOD. PTW is reset to ‘0’ when the
device junction temperature is less than T_PTW and
SIDLD selects LOD.
T_J < T_PTW
‘1’
‘0’
PTW is set to ‘1’ when device
junction temperature is greater
than T_PTW.
‘0’
TEF is reset to ‘0’at LAT riging edge for
on/off data writing when the device junction
temperature is less than T_TEF and SIDLD
‘1’
selects LOD.
‘0’
TEF is set to ‘1’ when device junction
temperture is grerater than T_TEF.
Figure 31. TEF/PTW/ISF Timing (LOD selected)
T_J ³ T_PTW
T_J ³ T_TEF
‘1’
‘1’
Table 13. TEF/PTW/ISF Truth Table
TEF
Device temperature is lower than
high-side detect temperature
(temperature ≤ T_TEF)
Device temperature is higher
than high-side detect
temperature and all outputs are
forced off (temperature >T_TEF)
PTW
Device temperature is lower than
pre-thermal warning temperature
(temperature ≤ T_PTW)
Device temperature is higher
than pre-thermal warning
temperature
(temperature > T_PTW)
ISF
IREF terminal is not shorted
IREF terminal is shorted to GND
with low impedance and all
outputs (OUT0 to OUT15) are
forced off
CORRESPONDING DATA BITS
IN SID
Depends on LOD/LSD/OLD
SID is all 1s for TEF when SIDLD
bit = '01'. SID is all 1s for PTW
when SIDLD = '10'. SID is all 1s
for ISF when SIDLD = '11'.
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