STATUS INFORMATION DATA (SID)

LOD/LSDHolder(24Bits)andTEFHolder(1Bit)

LODor

LSDfor

OUTG7

LODor

LSDfor

OUTB7

LODor

LSDfor

OUTG6

Thermal

Error

Flag

¼

LODor

LSDfor

OUTR7

LODor

LSDfor

OUTB6

LODor

LSDfor

OUTR1

LODor

LSDfor

OUTG0

LODor

LSDfor

OUTG1

LODor

LSDfor

OUTB0

LODor

LSDfor

OUTR0

LODor

LSDfor

OUTB1

CommonShiftRegister(25Bits)

LSB

Bit22

Bit23

Bit19

MSB

Bit24

¼

Bit21

Bit20

Bit3

Bit1

Bit4

Bit2

Bit0

SOUT

SCK

SIN

Bit5

SIDareloadedtothe

commonshiftregister

attherisingedgeofLAT

whenthecommonshift

registerMSBis ‘0’.

LED OPEN DETECTION (LOD), LED SHORT DETECTION (LSD), AND THERMAL ERROR FLAG

TLC5952

The 25-bit word status information data (SID) contains the status of the LED open detection (LOD) or LED short

detection (LSD), and thermal error flag (TEF). When the MSB of the common shift register is set to '0', the SID

overwrites the common shift register data at the rising edge of LAT after the data in the common shift register are

copied to the output on/off data latch. If the common shift register MSB is '1', the SID data are not copied to the

common shift register.

After being copied into the common shift register, new SID data are not available until new data are written into

the common shift register. If new data are not written, the LAT signal is ignored. To recheck SID data without

changing the constant-current output on/off data, reprogram the common shift register with the same data that

are currently programmed into the output on/off data latch. When LAT goes high, the output on/off data do not

change, but new SID data are loaded into the common shift register. LOD, LSD, and TEF are shifted out of

SOUT with each rising edge of SCLK.

Figure 35. SID Load Assignment

(TEF)

LOD detects a fault caused by an LED open circuit or a short from OUTRn/Gn/Bn to ground by comparing the

OUTRn/Gn/Bn voltage to the LOD detection threshold voltage level set in the control data latch (Table 4). If the

OUTRn/Gn/Bn voltage is lower than the programmed voltage, that output LOD bit is set to '1' to indicate an open

LED. Otherwise, the LOD bit is set to '0'. LOD data are only valid for outputs programmed to be on. LOD data for

outputs programmed to be off are always '0'.

LSD data detects a fault caused by a shorted LED by comparing the OUTRn/Gn/Bn voltage to the LSD detection

threshold voltage level set in the control data latch (Table 4). If the OUTRn/Gn/Bn voltage is higher than the

programmed voltage, that output LOD bit is set to '1' to indicate a shorted LED. Otherwise, the LSD bit is set to

'0'. LSD data are only valid for outputs programmed to be on. LSD data for outputs programmed to be off are

always '0'.

LOD/LSD data are not valid until 1

µs after the falling edge of BLANK. Therefore, BLANK must be low for at least

1

µs before going high. At the rising edge of BLANK, the LOD/LSD detection data are latched in the LOD/LSD

holder. Changes in the LOD/LSD data while BLANK is low are directly connected to the output of the LOD/LSD

holder, but are only valid 1

µs after the change. The rising edge of LAT transfers the output data of the LOD/LSD

holder to the common shift register.

22

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