AN3981 datasheet(21/54 Pages) STMICROELECTRONICS

tên linh kiện	AN3981

Giải thích chi tiết về linh kiện	LED array drivers

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21 / 54 page

AN3981

16-bit LED array drivers

Doc ID 022217 Rev 1

21/54

Figure 21.

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 STP16DPxy05 can detect these faulty conditions

(in accordance with the detection thresholds of Table 3) and provide the results of the

detection as an “Error status code” coming out of the SDO pin (see Figure 22), with “0” logic

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

Figure 22.

Error status code

Table 3.

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 = 2.4 V

Short on LED or short to LED supply voltage

VO = 2.2 V

No error detected

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