TLC59711 Datasheet, PDF (25/36 Pages) Texas Instruments – 12-Channel, 16-Bit, Enhanced Spectrum PWM, RGB, LED Driver

TLC59711
www.ti.com
SBVS181 – OCTOBER 2011
WATCHDOG TIMER FUNCTION
This function is enabled when SCKI clock is selected as GS reference clock by EXTGCK (bit 216) in the data
latch. When EXTGCK bit is '1', if SCKI rising edge does not change for 8x the period between the last SCKI
rising edge and the second to last SCKI rising edge with any accident, all OUTXn is forced off and GS clock
counter is reset to “0” to avoid displaying unexpected image.
Figure 31 shows the watchdog operation timing when SCKI rising edge is not changed with EXTGCK bit is ‘1’.
BLANK Bit
in Data Latch
(Internal)
EXTCLK Bit
in Data Latch
(Internal)
1
0
1 = SCKI is used for OUTXn on-off timing control.
OUTTMG Bit
in Data Latch
(Internal)
1 = OUTXn on-off state is changed at the rising edge of the clock selected by the EXTCLK bit.
The watchdog forces all OUTXn off when SCKI stops at a high
level or low level, regardless of the shift register data.
SCKI
OFF
1
2
¼
Period A
8x Period A
ON
OFF
OUTG0-G3
ON
OFF
OUTB0-B3
ON
Figure 30. Watchdog Operation Timing with no SCKI Clock Input (OUTTMG = 1)
THERMAL SHUTDOWN
The thermal shutdown (TSD) function turns off all IC constant-current outputs when the junction temperature (T_J)
exceeds the threshold (T_TSD = +165°C, typ). When the junction temperature drops below (T_TSD – T_HYS), the
output control starts at the first GS clock in the next display period.
NOISE REDUCTION
Large surge currents may flow through the IC and the board if all 12 outputs turn on simultaneously at the start of
each GS cycle. These large current surges could induce detrimental noise and EMI into other circuits. The
TLC59711 turns on the outputs for each color group independently with a 25 ns (typ) rise time. The output
current sinks are grouped into three groups. The first group that is turned on/off are OUTR0-3; the second group
that is turned on/off are OUTG0-3; and the third group is OUTB0-3. However, the state of each output is
controlled by the selected GS clock; see the Output Timing Select Function section.
Copyright © 2011, Texas Instruments Incorporated
Product Folder Link(s): TLC59711
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