AS1109-BSOU austriamicrosystems, AS1109-BSOU Datasheet - Page 15

• Manufacturer Part Number: AS1109-BSOU
• Description: IC DRIVER LED 4-BIT CC 16-SOIC
• Manufacturer: austriamicrosystems
• Type: General Purposer

Specifications of AS1109-BSOU

• Constant Current: Yes
• Topology: 8-Bit Shift Register, PWM
• Number Of Outputs: 8
• Internal Driver: Yes
• Type - Primary: General Purpose
• Frequency: 50MHz
• Voltage - Supply: 3 V ~ 5.5 V
• Voltage - Output: 15V
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• Operating Temperature: -40°C ~ 85°C
• Current - Output / Channel: 100mA
• Internal Switch(s): Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Efficiency: -

AS1109
Datasheet - D e t a i l e d D e s c r i p t i o n
Detailed Shorted-LED Error Report
The detailed shorted-LED error report can be read out immediately after global error mode has been run
Figure 17. Detailed Shorted-LED Error Report Timing Diagram
Detailed Shorted-LED Error Report Example
Consider a case where five AS1109s are cascaded in one chain. A 1 indicates a LED is on, a 0 indicates a LED is off, and an X indicates a
shorted LED. This test is used with a test pattern where all LEDs are on at test time. Additionally, this test should be run after starting low-current
diagnostic mode
IC2 has two shorted LEDs and IC4 has one shorted LED switched on due to input. 5*8 clock cycles are needed to write the entire error code out.
The detailed error report would look like this:
Showing IC1 as the device with two shorted LEDs at position 6 and 7, and IC4 with one shorted LED at position 4.
Note: In an actual report there are no spaces in the output. LEDs turned off during test time cannot be tested.
Low-Current Diagnostic Mode
To run the open- or shorted-LED test, a test pattern must be used that will turn on each LED to be tested. This test pattern will cause a short
flicker on the screen while the test is being performed. The low-current diagnostic mode can be initiated prior to running a detailed error report to
reduce this on-screen flickering.
Note: Normally, displays using such a diagnosis mode require additional cables, resistors, and other components to reduce the current. The
Low-current diagnostic mode can be initiated via 3 clock pulses during error-detection mode. After the falling edge of LD, a test pattern displaying
all 1s can be written to the shift register which will be used for the next error-detection test.
On the next falling edge of OEN, current is reduced to I
els and the detailed error report can be read out entering error-detection mode.
www.austriamicrosystems.com/LED-Driver-ICs/AS1109
For detailed timing information see
SDO
OEN
CLK
SDI
LD
AS1109 has this current-reduction capability built-in, thereby minimizing the number of external components required.
Failure Code: 1 1 1 1 1 0 0 1
LED Status: 1 1 1 1 1 X X 1
(see Low-Current Diagnostic Mode on page
Input Data: 1 1 1 1 1 1 1 1
t
GSW(ERROR)
t
TESTING
T
T
FLAG
FLAG
t
t
Global Flag Readout
Global Flag Readout
SU(ERROR)
GSW(ERROR)
t
Timing Diagrams on page
P4
O
FLAG
IC1:[11111XX1] IC2:[11111111] IC3:[11111111] IC4:[111X1111] IC5:[11111111]
t
SW(ERROR)
t
GSW(ERROR)
S
9.
FLAG
1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1
LC
. With the next rising edge of OEN the current will immediately increase to normal lev-
t
t
P4
H(L)
15).
DBit7
SBit7
Revision 1.20
DBit6
Shorted-LED Error Report Output
1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1
Detailed Error Report Readout
SBit6
DBit5
SBit5
New Data Input
DBit4
SBit4
DBit3
SBit3
1 1 1 1 1 1 1 1
1 1 1 X 1 1 1 1
1 1 1 0 1 1 1 1
DBit2
SBit2
DBit1
(see Global Error Mode on page
SBit1
DBit0
SBit0
1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1
t
P1
Don’t
Don’t
Care
Care
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11).