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

Revision 1.21

15 - 24

AS1109

Datasheet - Detailed Descr i p ti on

Figure 18. Switching into Low-Current Diagnostic Mode Timing Diagram

8.7 Shutdown Mode

The AS1109 features a shutdown mode which can be entered via 4 clock pulses during error-detection mode. To enable the shutdown mode a 0

must be placed at SDI after the rising edge of the 3rd clock pulse.

To disable shutdown mode a 1 must be placed at SDI after the 3rd clock pulse. The shutdown/wakeup information will be latched through if

multiple AS1109 devices are in a chain. At the rising edge of the 4th clock pulse the shutdown bit will be read out and the AS1109 will shutdown

or wakeup.

Note:

In shutdown mode the supply current drops down to typically 3µA.

Figure 19. Shutdown Mode Timing Diagram

OFLAG

TFLAG

SFLAG

Don’t

Care

Re-entering Error Detection

Mode

tTESTING

Global Flag Readout

SDI

OEN

LD

CLK

SDO

Load Internal all 1s Test

Pattern

(optional)

tH(L)

tP4

tSW(ERROR)

tP1

tSU(ERROR)

Normal Operation Current

For detailed timing information see Timing Diagrams on page 8.

tGSW(ERROR)

tGSW(ERROR)

tGSW(ERROR)

2µs Low-Current Diagnosis Mode

tH(L)

SDI

OEN

LD

CLK

SDO

1 = Wakeup

0 = Shutdown

1 = Wakeup

0 = Shutdown

OFLAG

TFLAG

SFLAG

tP4

tSU(ERROR)

tSU(D)