TLC5926-Q1_16 Datasheet, PDF (15/36 Pages) Texas Instruments – TLC592x-Q1 16-Channel Constant-Current LED Sink Drivers

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TLC5926-Q1, TLC5927-Q1
SLVS973A – SEPTEMBER 2009 – REVISED JULY 2015
9.3.3 Overtemperature Detection and Shutdown
The TLC592x-Q1 is equipped with a global overtemperature sensor and 16 individual, channel-specific
overtemperature sensors.
• When the global sensor reaches the trip temperature, all output channels are shutdown, and the error status
is stored in the internal Error Status register of every channel. After shutdown, the channels automatically
restart after cooling down, if the control signal (output latch) remains on. The stored error status is not reset
after cooling down and can be read out as the error status code in the Special mode.
• When one of the channel-specific sensors reaches trip temperature, only the affected output channel is shut
down, and the error status is stored only in the internal Error Status register of the affected channel. After
shutdown, the channel automatically restarts after cooling down, if the control signal (output latch) remains
on. The stored error status is not reset after cooling down and can be read out as error status code in the
Special mode.
For channel-specific overtemperature error detection, a channel must be on.
The error status code is reset when the TLC592x-Q1 returns to Normal mode.
Table 3. Overtemperature Detection⁽¹⁾
STATE OF OUTPUT PORT
Off
On
On → all channels
Off
On
On → Off
CONDITION
I_OUT = 0 mA
T_j < T_j,trip global
T_j > T_j,trip global
T_j < T_j,trip channel n
T_j > T_j,trip channel n
ERROR STATUS CODE
0
1
All error status bits = 0
1
Channel n error status bit = 0
(1) The global shutdown threshold temperature is approximately 170°C.
MEANING
Normal
Global overtemperature
Normal
Channel n overtemperature
9.4 Device Functional Modes
The TLC5926/TLC5927-Q1 provides a Special Mode in which two functions are included: Error Detection and
Current Gain Control. In the TLC5926/TLC5927-Q1 there are two operation modes and three phases: Normal
Mode phase, Mode Switching transition phase, and Special mode phase. The signal on the multiple- function pin
OE(ED2) is monitored, and when a one- clock-wide short pulse appears on OE(ED2), TLC5926/TLC5927-Q1
enters the Mode Switching phase. At this time, the voltage level on LE (ED1) determines the next mode into
which the TLC5926/TLC5927-Q1 switches.
In the Normal Mode phase, the serial data is transferred into TLC5926/TLC5927-Q1 via SDI, shifted in the shift
register, and transferred out 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.
In the Special Mode phase, the low-voltage-level signal OE(ED2) can enable output channels and detect the
status of the output current, to tell if the driving current level is enough or not. The detected error status is loaded
into the 16-bit shift register and shifted out via SDO, along with the CLK signal. The system controller can read
the error status to determine whether or not the LEDs are properly lit. In the Special Mode phase,
TLC5926/TLC5927-Q1 also allows users to adjust the output current level by setting a runtime-programmable
Configuration Code. The code is sent into TLC5926/TLC5927-Q1 via SDI. The positive pulse of LE (ED1) latches
the code in the shift register into a built-in 8-bit configuration latch, instead of the output latch. The code affects
the voltage at R-EXT and controls the output-current regulator. The output current can be adjusted finely by a
gain ranging from 1/12 to 127/128 in 256 steps. Therefore, the current skew between ICs can be compensated
within less than 1%, and this feature is suitable for white balancing in LED color-display panels.
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Product Folder Links: TLC5926-Q1 TLC5927-Q1