TLC59291_15 Datasheet, PDF (26/45 Pages) Texas Instruments – TLC59291 8/16-Channel, Constant Current LED Driver with 7-bit Brightness Control Low Quiescent Current and Full Self Diagnosis for LED Lamp

TLC59291
SLVSA96 – SEPTEMBER 2015
www.ti.com
8.3.5 Current Reference Terminal – IREF Terminal - Short Flag (ISF)
The ISF function indicates that IREF terminal is short to GND with low impedance. When IREF is set, all OLD
data bit is set to “1”. Then all outputs (OUTn) are forced off and remain off until the short is removed. Table 3
shows the truth table for ISF.
Table 3. 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'.
8.3.6 Noise Reduction
Large surge currents may flow through the IC and the board on which the device is mounted if all 16 outputs turn
on simultaneously when BLANK goes low or on-off data changes at LAT rising edge with BLANK low. These
large current surges could induce detrimental noise and electromagnetic interference (EMI) into other circuits.
The TLC59291 turns the outputs on in 2ns series delay for each output to provide a circuit soft-start feature.
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