16-bit Constant Current LED Driver with Error Detection

Version:A.002

Page 20

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DM13G

MODE

CLK

LAT

Error Detection

Time

ENB

Error Report Time

. . .

ALARM

Reset to “H＂

Thermal Error Report

Open/short or Output short Error Report

For actual application, the controller could connect all the ALARM pins with one

pull-high resistor to simplify circuit designs and feedback loops.

Thermal Alarm and Shutdown

During operation, when the junction temperature of the IC reaches about 130℃, the

ALARM pin will shift to low level and produce a warning signal (ENB=”H”). Suggested

cooling measures is to start the fan, lower the output currents and etc. If no cooling

measures were activated, the junction temperature might continue to rise. Once it reaches

approximately above 170℃, it will cause the driver to shutdown all the outputs. Basically,

the IC will cool down and return to the safe operating temperature which is approximately

below 130℃. The ALARM pin will reset to high level, disable the warning, and restart all the

outputs at the same time. Operation in the thermal situation for a long time may cause chip

damage permanently.

Normal

Alarm

Normal

Normal

Normal

Alarm

Alarm + Shutdowm

130 C

170 C

Ghost Image Elimination

DM13G provide a function of ghost image elimination. When users turn off the output

channel, the ghost image elimination circuit will pull up the output voltage to “VLED-0.7V”. It

can make sure the output channels are fully turned off.