TLC5948A Datasheet, PDF (42/50 Pages) Texas Instruments – 16-Channel, 16-Bit, ES-PWM, Full Self-Diagnosis LED Driver

TLC5948A
SBVS192 – MARCH 2012
www.ti.com
THERMAL SHUTDOWN (TSD) AND THERMAL ERROR FLAG (TEF)
The TSD function turns off all constant-current outputs on the device when the junction temperature (T_J) exceeds
the threshold (T_TEF = +165°C, typ) and sets TEF to '1'. All outputs are latched off when TEF is set to '1' and
remain off at least until the next GS cycle starts and the junction temperature drops below (T_TEF – T_HYST). TEF
remains '1' until a LAT rising edge occurs and the temperature is reduced. TEF is set to '0' once the junction
temperature drops below (T_TEF – T_HYST), but the output does not turn on until the first GSCLK in the next display
period occurs even if TEF is set to '0'. See Figure 37 for a timing diagram; refer to Table 18 for the TEF truth
table.
NOISE REDUCTION
Large surge currents may flow through the device and the board on which the device is mounted if all 16 outputs
turn on simultaneously at the start of each GS cycle. These large current surges could introduce detrimental
noise and electromagnetic interference (EMI) into other circuits. The TLC5948A independently turns the outputs
on with a delay for each group to provide a soft-start feature. The output current sinks are grouped into four
groups in each color group. The first output group that is turned on/off are OUT0, 7, 8, and 15; the second output
group is OUT1, 6, 9, and 14; the third output group is OUT2, 5, 10, and 13; and the fourth output group is OUT3,
4, 11, and 12. Each output group is turned on and off sequentially with a small delay between the groups.
However, each output on/off is controlled by the GS clock.
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