TLC5949PWPR datasheet(41/51 Pages) TI

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TLC5949

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SBVS219A – DECEMBER 2012 – REVISED DECEMBER 2012

THERMAL SHUTDOWN (TSD) AND THERMAL ERROR FLAG (TEF)

The TSD function turns off all constant-current outputs on the device when the junction temperature (TJ) exceeds

the threshold (TTEF = +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 (TTEF – THYST). TEF

remains '1' until a LAT rising edge occurs and the temperature is reduced. TEF is set to '0' when the junction

temperature drops below (TTEF – THYST), 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 34 for a timing diagram; refer to Table 15 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 TLC5949 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, OUT7, OUT8, and OUT15; the second

output group is OUT1, OUT6, OUT9, and OUT14; the third output group is OUT2, OUT5, OUT10, and OUT13;

and the fourth output group is OUT3, OUT4, OUT11, and OUT12. 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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TLC5949PWPR Datasheet(PDF) 41 Page - Texas Instruments