The LED short detection (LSD) function detects faults caused by a short circuit in any LED. This function was realized by comparing the OUTn voltage to the LSD threshold voltage. If the OUTn voltage is lower than the threshold voltage, the corresponding output LSD bit is set to 1 to indicate an short LED, otherwise, the output of that LSD bit is 0. LSD data output by the detection circuit are valid only during the OUTn turning on period.

LSD weak short can be detected by adjusting threshold voltage, which level is set by LSDVTH_R/LSDVTH_G/LSDVTH_B (See FC3 for more details).

Figure 7-12 shows the equivalent circuit of LED short detection.

The LED short detection function records the position of the short LED, which contains the scan line order and relevant channel number. The scan line order is stored LSD_LINE_WARN register (see FC18, FC19 for more details), and the channel number is latched into the internal 48-bit LSD data register (see FC21 for more details) at the end of each segment. Figure 7-13 shows the bit arrangement of the LSD data register.

Figure 7-13 Bit Arrangement in the LSD Data Register