LP5890 datasheet(21/72 Pages) TI

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Figure 8-8. LED Open Caterpillar

The LP5890 implements circuits that can eliminate the caterpillar issue caused by open LEDs. The LED open

caterpillar removal function is configured by LODRM_EN (fore more details, see FC0). When LODRM_EN is set

to 1b, the caterpillar removal function is enabled. The corresponding channel OUTn is turned off when scanning

to line with open LED. The caterpillar issue is eliminated until device resets or LODRM_EN is set to 0b.

The internal caterpillar elimination circuit can handle a maximum of three lines that have open LEDs fault

condition. If there are open LEDs located in three or fewer lines, the LP5890 is able to handle the open LEDs all

in these lines. If there are open LEDs in more than three lines, the caterpillar issue is solved for the lines where

the first three open LEDs were detected, but the open LEDs in the fourth and subsequent lines still cause the

caterpillar issue.

8.3.5.4 LED Short and Weak Short Circuitry Detection and Removal

8.3.5.4.1 LED Short and Weak Short Detection

The LED Short Detection (LSD) function detects faults caused by a short circuit in any LED. LSD was realized

by comparing the OUTn voltage to the LSD threshold voltage. If the OUTn voltage is lower than the threshold

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LP5890

SLVSGD5 – JULY 2021

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LP5890 Datasheet(PDF) 21 Page - Texas Instruments