Ver2.1

21

LD1024

16-Channel, Constant-Current LED Driver with LED Open Detection

STATUS INFORMATION DATA (SID)

The latched LED open detection (LOD) error and pre-thermal warning (PTW) in the SID data latch are shifted out

onto the DOUT pin with each rising edge of CLK. If a PTW is reported, all LOD error bits are set to '1'. The SID

data are written over the data in the on/off control shift register at the rising edge of LAT. Therefore, the previous

data in the on/off control shift register are lost when SID information is latched in. Figure 20 shows the SID bit

assignments. See Figure 7 for the read timing of SID.

When the IC is powered on, the initial LOD data are invalid. Therefore, LOD data must be read after the rising

edge of OEB. Table 3 shows a truth table for LOD and PTW

CONDITION

SID DATA

LED open detection

(LODn)

'0' (low level at DOUT)

'1' (high level at DOUT); set to the

bit that has an LED error condition

Pre-thermal

Warning(PTW)

Depend LED open error

All bits = '1' (high level at DOUT)

Table 2. LOD and PTW Truth Table

Figure 15. Status Information Data Configuration

OUT15

LOD Data

(LOD 15)

15

OUT15

LOD Data

(LOD 14)

14

OUT15

LOD Data

(LOD 13)

13

OUT15

LOD Data

(LOD 12)

12

OUT15

LOD Data

(LOD 3)

OUT15

LOD Data

(LOD 2)

OUT15

LOD Data

(LOD 1)

OUT15

LOD Data

(LOD 0)

3

2

1

0

LSB

MSB

11

4

On/Off Data

for

OUT15

15

On/Off Data

for

OUT14

14

On/Off Data

for

OUT13

13

On/Off Data

for

OUT12

12

On/Off Data

for

OUT3

On/Off Data

for

OUT2

On/Off Data

for

OUT1

On/Off Data

for

OUT0

3

2

1

0

LSB

MSB

11

4

DIN

CLK

SID Data Latch (1 Bit x 16

Channels)

SID Control Shift Register (1 Bit x 16 Channels)

All Bits Become ‘1’ When the IC is in a PTW (Pre-Thermal Warning)

Condition

DOUT

The 16 bits in the SID latch are loaded into the on/off shift register at the rising edge of LAT.