LP5891 datasheet(21/74 Pages) TI

21 / 74 page

Figure 7-11. LED Open Caterpillar

The LP5891 implements circuits that can eliminate the caterpillar issue caused by open LEDs. The LED open

caterpillar removal function is configured by LOD_RM_EN (see FC0 for more details). When LOD_RM_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 LOD_RM_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 LP5891 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.

7.3.5.4 LED Short and Weak Short Circuitry Detection and Removal

7.3.5.4.1 LED Short/Weak Short Detection

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

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LP5891

SLDS269A – MARCH 2022 – REVISED MAY 2022

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LP5891 Datasheet(PDF) 21 Page - Texas Instruments