TLC5916-Q1_16 Datasheet, PDF (20/34 Pages) Texas Instruments – 8-Bit Constant-Current LED Sink Drivers

TLC5916-Q1, TLC5917-Q1
SLVS814A – JANUARY 2008 – REVISED MAY 2015
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CLK
Switching to Special Mode
1
2
3
4
5
CLK
Switching to Normal Mode
1
2
3
4
5
OE(ED2) ¹
0
1
1
1
LE(ED1) ⁰
0
0
1
0
OE(ED2) ¹
0
1
1
1
LE(ED1) ⁰
0
0
0
0
Actual Mode
Mode
Special
Phase _{(Normal or Special) Switching Mode}
Actual Mode
Mode
Normal
Phase _{(Normal or Special) Switching Mode}
Figure 15. Mode Switching
As shown in Figure 15, once a one-clock-wide short pulse (101) of OE(ED2) appears, TTLC591x-Q1 enters the
Mode Switching phase. At the fourth rising edge of CLK, if LE(ED1) is sampled as voltage high, TLC591x-Q1
switches to Special mode; otherwise, it switches to Normal mode. The signal LE(ED1) between the third and the
fifth rising edges of CLK cannot latch any data. Its level is used only to determine into which mode to switch.
However, the short pulse of OE(ED2) can still enable the output ports. During mode switching, the serial data
can still be transferred through SDI and shifted out from SDO.
NOTE
1. The signal sequence for the mode switching may be used frequently to ensure that TLC591x-
Q1 is in the proper mode.
2. The 1 and 0 on the LE(ED1) signal are sampled at the rising edge of CLK. The X means its
level does not affect the result of mode switching mechanism.
3. After power on, the default operation mode is Normal mode.
9.4.1.1 Normal Mode Phase
Serial data is transferred into TLC591x-Q1 via SDI, shifted in the Shift register, and output via SDO. LE(ED1) can
latch the serial data in the Shift register to the Output Latch. OE(ED2) enables the output drivers to sink current.
These functions differ only as described in Operation Mode Switching, in which case, a short pulse triggers
TLC591x-Q1 to switch the operation mode. However, as long as LE(ED1) is high in the Mode Switching phase,
TLC591x-Q1 remains in the Normal mode, as if no mode switching occurred.
9.4.1.2 Special Mode Phase
In the Special mode, as long as OE(ED2) is not low, the serial data is shifted to the Shift register via SDI and
shifted out via SDO, as in the Normal mode. However, there are two differences between Special mode and
Normal mode, as shown in the following sections.
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