16-bit Constant Current LED Driver with Error Detection

Version:A.006

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DM13C

Thermal Shutdown

During operation, when the junction temperature of the IC will reach approximately above

180℃, 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 110℃. DM13C will restart

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

damage permanently.

normal (high temperature)

110°C

180°C

T(°C)

Relations between Thermal Shutdown and Junction Temperature

normal

shutdown

normal

LED Open/Short Detection

The result of open/short detection of DM13C could be retrieved from serial-out (DAO) data. It

will be identified as a LED open failure when the output is turned on but the output voltage is below

0.3V. And then it will be identified as a LED short failure when the output is turned on but the

output voltage is above 1/2 VCC.

To set up with the following conditions: (1) the image data written in shift register

corresponding to particular output channel is ‘1’; (2) the output enable terminal is activated

(EN=‘L’); (3) the rising edge of the latch signal (LAT), DM13C will execute LED open/short

detection then renews the results within the corresponding shift register.

By using the error message retrieved from serial-out data, system can recognize the status of

every LED driven by each channel. For either LED open or short detection, the original image data

is written to ‘1’ but ‘0’ is retrieved then a LED failure has occurred. If the image data is written to

‘0’ or the output enable terminal is inactive (EN=‘H’), it will not execute any detection process for

the corresponding channel. Therefore, system still retrieves the original image data.