TLC5904

LED DRIVER

SLLS391 – NOVEMBER 1999

17

POST OFFICE BOX 655303

PRINCIPLES OF OPERATION

output signal check for XDOWN1, XDOWN2

XDOWN1 or XDOWN2 can be forced to low level by setting the appropriate latch value for OVM. This allows

the investigation of the correct connection of XDOWN1 or XDOWN2 to the external system.

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 is tied to the low level.

Table 5. OVM Setting

MONITOR CONTROL

DATA

COMPARISON

VOLTAGE

XDOWN1

XDOWN2

MSB

LSB

VOLTAGE

0000

NO COMPARISON

DEPEND ON TSD/WDT

HI–Z

0001†

0.3 V

DEPEND ON TSD/WDT

DEPEND ON OVM COMPARATOR

0010

0.4 V

DEPEND ON TSD/WDT

DEPEND ON OVM COMPARATOR

0011

0.5 V

DEPEND ON TSD/WDT

DEPEND ON OVM COMPARATOR

0100

0.6 V

DEPEND ON TSD/WDT

DEPEND ON OVM COMPARATOR

0101

0.7 V

DEPEND ON TSD/WDT

DEPEND ON OVM COMPARATOR

0110

0.8 V

DEPEND ON TSD/WDT

DEPEND ON OVM COMPARATOR

0111

0.9 V

DEPEND ON TSD/WDT

DEPEND ON OVM COMPARATOR

1000

1.0 V

DEPEND ON TSD/WDT

DEPEND ON OVM COMPARATOR

1001

1.1 V

DEPEND ON TSD/WDT

DEPEND ON OVM COMPARATOR

1010

1.2 V

DEPEND ON TSD/WDT

DEPEND ON OVM COMPARATOR

1011

1/3

× VCCANA

DEPEND ON TSD/WDT

DEPEND ON OVM COMPARATOR

1100

1/2

× VCCANA

DEPEND ON TSD/WDT

DEPEND ON OVM COMPARATOR

1101

2/3

× VCCANA

DEPEND ON TSD/WDT

DEPEND ON OVM COMPARATOR

1110

0.3 V

L

DEPEND ON OVM COMPARATOR

1111

0.3 V

DEPEND ON TSD/WDT

L

† MCENA is low.

DOUT output timing selection

The timing for the DOUT output change can be switched by selecting the DOMODE level. When DOMODE is

low, the DOUT is changed synchronizing to the rising edge of DCLK. When DOMODE is high, the DOUT is

changed synchronizing to the falling edge of DCLK. When the shift operation with DOMODE is high, data can

be protected from a shift error even if the DCLK signal is buffered externally in serial. In this case, when ICs are

connected in cascade, the maximum data transfer speed at will be slower than the case of DOMODE low.