AN3981 datasheet(13/54 Pages) STMICROELECTRONICS

tên linh kiện	AN3981

Giải thích chi tiết về linh kiện	LED array drivers

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13 / 54 page

AN3981

8-bit LED array drivers

Doc ID 022217 Rev 1

13/54

Figure 10.

Fault conditions detected by error detection mode: a) shorted LED; b)

open LED; c) short-circuit from current generator to VLED; d) open

channel; e) short-circuit from current generator to GND

The diagnostic circuitry embedded in the STP08DP05 can detect these faulty conditions (in

accordance with the detection thresholds of Table 1) and provide the results of the detection

as an “Error status code” coming out of the SDO pin (see Figure 11), with “0” logic level

indicating a faulty channel, whereas a “1” logic level indicates a “good” channel.

Table 1.

Detection conditions

Detection result

IODEC

(1) = 0.5·I

(2)

IODEC is the detected output current in detection mode.

IO is the programmed output current.

Open channel or output short to GND detected

IODEC = 0.5·IO

No error detected

VO = 2.5 V

LED short-circuit or LED shorted to supply voltage

VO = 2.2 V

No error detected

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