TLC5947 Datasheet, PDF (17/25 Pages) Texas Instruments – 24-Channel, 12-Bit PWM LED Driver with

TLC5947
www.ti.com....................................................................................................................................................................................................... SBVS114 – JULY 2008
AUTO DISPLAY REPEAT FUNCTION
This function can repeat the total display period without any timing control signal, as shown in Figure 21.
BLANK
GS Counter Value
Internal Oscillator Clock
2048
4095
2048
4095
¼
¼
¼
¼
0 0 0 0 1 2 3 2047 2049 4094 0 1 2 3 2047 2049 4094 0
4095
¼
1 2 3 0 0 0 0 0 0 1 2 4094 4096 1 2
Grayscale counter starts to count from the fifth clock _{Display period is turned on again by}
of the internal oscillator clock after BLANK goes low. _{the auto display repeat function.}
OUTn ^OFF
(GS Data = 001h) _ON
OUTn ^OFF
(GS Data = 800h) _ON
OUTn ^OFF
(GS Data = FFFh) _ON
First Display Period
(4096 Internal Clock)
Four Internal Clock Intervals After BLANK Goes Low
Second Display Period
(4096 Internal Clock)
Nth Display Period
First
Display Period
Second
Display Period
Four Internal Clock Intervals After BLANK Goes Low
Figure 21. Auto Display Repeat Operation
THERMAL SHUTDOWN (TSD)
The thermal shutdown (TSD) function turns off all constant current outputs immediately when the IC junction
temperature exceeds the high temperature threshold (T_(TEF) = +162° C, typ). The outputs will remain disabled as
long as the over-temperature condition exists. The outputs are turned on again at the first clock after the IC
junction temperature falls below the temperature of T_(TEF) – T_(HYS). Figure 22 shows the TSD operation.
IC Junction Temperature (T_J)
T_J < T_(TEF) - T_(HYS)
T_J ³ T_(TEF)
T_J < T_(TEF) - T_(HYS)
T_J ³ T_(TEF)
BLANK
High
Low
Internal Oscillator Clock
1 23
4096
4095 1 2
4096
4095 1 2
4096
4095 1 2
4096
4095 1 2
4096
4095 1 2
4096
4095 1 2
OFF
OUTn
(GS Data = FFFh)
ON
OFF
OFF
ON
Figure 22. TSD Operation
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