AS1109 데이터 시트보기 (PDF) - austriamicrosystems AG

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AS1109

Constant-Current, 8-Bit LED Driver with Diagnostics

austriamicrosystems AG 

AS1109

Datasheet - Detailed Description

8.6 Detailed Error Reports

The detailed error report can be read out after global error mode has been run. On the falling edge of LD, the detailed error report of the selected

test is latched into the shift register and can be clocked out with n*8 clock cycles (n is the number of AS1109s in a chain) via pin SDO. At the

same time new data can be written into the shift register, which will load on the next rising edge of pin LD. This data will show at the output

drivers, at the falling edge of OEN.

8.6.1 Detailed Temperature Warning Report

The detailed temperature warning report can be read out immediately after global error mode has been run. Bit0 of the 8bit data word represents

the temperature flag of the chip.

Figure 15. Detailed Temperature Warning Report Timing Diagram

Global Flag Readout

Detailed Error Report Readout

OEN

LD

CLK

tGSW(ERROR)

t(SU)ERROR

tH(L)

tP4

SDI

SDO

TFLAG

tP4

For detailed timing information see Timing Diagrams on page 8.

DBit7

DBit6 DBit5 DBit4 DBit3 DBit2 DBit1 DBit0

New Data Input

Undefined

TBit0

Temperature Error Report Output

tP1

Don’t

Care

Don’t

Care

Detailed Temperature Warning Report Example

Consider a case where five AS1109s are cascaded in one chain. The detailed error report lists the temperatures for each device in the chain:

IC1:[70°] IC2:[85°] IC3:[66°] IC4:[160°] IC5:[76°]

In this case, IC4 is overheated and will generate a global error, and therefore 5*8 clock cycles are needed to write out the detailed temperature

warning report, and optionally read in new data. The detailed temperature warning report would look like this:

XXXXXXX1 XXXXXXX1 XXXXXXX1 XXXXXXX0 XXXXXXX1

The 0 in the detailed temperature warning report indicates that IC4 is the device with the over-temperature condition.

Note: In an actual report there are no spaces in the output.

www.ams.com/LED-Driver-ICs/AS1109

Revision 1.21

12 - 24

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