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TLC5905 Datasheet, PDF (17/27 Pages) Texas Instruments – LED DRIVER
PRINCIPLES OF OPERATION
TLC5905
LED DRIVER
SLLS401 – NOVEMBER 1999
OVM (output voltage monitor) function (continued)
output signal check for XDOWN1, XDOWN2
XDOWN1 or XDOWN2 can be forced to a low level by setting the appropriate latch value for OVM. This allows
investigation of the correct connection of XDOWN1 or XDOWN2 to the external system. Since both XDOWN1
and XDOWN2 terminal are open-collector outputs, outputs of multiple ICs are brought together.
OVM comparator setting
Setting the OVM latch is shown in Table 5. Note that the comparison voltage is set to the default value of 0.3 V
when MCENA tied to a low level.
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ MONITOR CONTROL DATA
MSB
LSB
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 0000
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 0001†
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 0010
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 0011
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 0100
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 0101
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 0110
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 0111
1000
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 1001
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 1010
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 1011
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 1100
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 1101
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 1110
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 1111
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ † MCENA is low.
Table 5. OVM Setting
COMPARISON
VOLTAGE
XDOWN1
XDOWN2
NO COMPARISON
0.3 V
0.4 V
0.5 V
0.6 V
0.7 V
0.8 V
0.9 V
1.0 V
1.1 V
1.2 V
1/3 × VCC(ANA)
1/2 × VCC(ANA)
2/3 × VCC(ANA)
0.3 V
0.3 V
DEPEND ON TSD/WDT
DEPEND ON TSD/WDT
DEPEND ON TSD/WDT
DEPEND ON TSD/WDT
DEPEND ON TSD/WDT
DEPEND ON TSD/WDT
DEPEND ON TSD/WDT
DEPEND ON TSD/WDT
DEPEND ON TSD/WDT
DEPEND ON TSD/WDT
DEPEND ON TSD/WDT
DEPEND ON TSD/WDT
DEPEND ON TSD/WDT
DEPEND ON TSD/WDT
L
DEPEND ON TSD/WDT
HI–Z
DEPEND ON OVM COMPARATOR
DEPEND ON OVM COMPARATOR
DEPEND ON OVM COMPARATOR
DEPEND ON OVM COMPARATOR
DEPEND ON OVM COMPARATOR
DEPEND ON OVM COMPARATOR
DEPEND ON OVM COMPARATOR
DEPEND ON OVM COMPARATOR
DEPEND ON OVM COMPARATOR
DEPEND ON OVM COMPARATOR
DEPEND ON OVM COMPARATOR
DEPEND ON OVM COMPARATOR
DEPEND ON OVM COMPARATOR
DEPEND ON OVM COMPARATOR
L
SOUT output timing selection
The timing for the SOUT output can be switched by selecting the SOMODE level. When SOMODE is low, SOUT
is clocked out synchronizing to the rising edge of SCLK. When SOMODE is high, SOUT is clocked out
synchronizing to the falling edge of SCLK. When the shift operation with SOMODE high, data can be protected
from shift error even if the SCLK signal is buffered in serial externally. In this case, when ICs are connected in
cascade, the maximum data transfer speed will be slower than the case of SOMODE low.
protection
This device incorporates WDT and TSD functions. If the WDT or TSD is turned on, then the constant current
output is stopped and XDOWN1 goes low. Therefore, by monitoring XDOWN1 terminal, these failures can be
detected immediately. Since the XDOWN1 output is configured as an open collector, outputs of multiple ICs are
brought together.
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