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The power-save mode (PSM) is enabled by setting PSM_EN to 1 in function-control register 2 (see FC2 in
Table
2-3). After power on, the default value of this bit is 0. When this function is enabled (PSM_EN = 1),
if all the grayscale (GS) data received for the next frame are 0, then the device enters power-save mode
at the moment the VSYNC command is input.
When operating in the power-save mode, the device continuously detects whether non-zero GS data is
input for the next frame. Among all the GS data for the next frame, if any non-zero data is detected, the
device resumes normal mode once finishing the whole GS input for the next frame.
Figure 2-19
shows the timing diagram of the power-save mode of operation.
Power-Save Mode:
Data Input
Write GS to BANK A
GCLK Signal
Display BANK B
Operating Mode
Normal Mode
Frame N ± 1
2.3.5 Thermal Shutdown (TSD)
The thermal shutdown (TSD) function turns off all device constant-current outputs when the junction
temperature (T
) exceeds 170°C (typical). It resumes normal operation when T
J
2.3.6 IREF Resistor Short Protection (ISP)
The IREF-resistor short-protection (ISP) function prevents unwanted large currents from flowing though
the constant-current output when the IREF resistor is shorted accidentally. The TLC694x device turns off
all output channels when the IREF pin voltage is lower than 0.19 V (typical). When the IREF pin voltage
goes higher than 0.325 V (typical), the TLC694x device resumes normal operation.
SLVUBF4A – February 2018 – Revised June 2019
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If all the GS data written during this period are 0, the
device enters the power-save mode at the falling edge
of the VSYNC command pulse on the LAT signal.
Write GS to BANK B
VSYNC
Display BANK A
Normal Mode
Frame N
Figure 2-19. Power-Save Mode
Copyright © 2018–2019, Texas Instruments Incorporated
Any non-zero data written during this
period causes the device to begin
returning to the normal mode after
receiving the last WRTGS command
at the falling edge of LAT.
Write GS to BANK A
VSYNC
Display BANK B
Start to Resume
Normal Mode
Power-Save Mode
Enter Power-Save
Mode Immediately
Frame N + 1
Function-Control Description
Write GS to BANK B
VSYNC
Display BANK A
Fully
50 µs
Recovered
t
> 50 µs
SU
Frame N + 2
falls below 155°C (typical).
J
Function Control
25
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