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AS1109-BSSU-Z

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P25
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 9 - 24
AS1109
Datasheet - Detailed Description
Figure 12. Data Input Timing Diagram
Figure 13. Data Input Example Timing Diagram
SDI
CLK
OEN
LD
SDO
8 CLK Pulses
tSU(OE)
tW(L)
tSU(L
tW(OE)
tH(D)
tP1
Data Bit
7
Data Bit
6
Data Bit
5
Data Bit
4
Data Bit
3
Data Bit
2
Data Bit
1
Data Bit
0
Old Data
Bit 7
Old Data
Bit 6
Old Data
Bit 5
Old Data
Bit 4
Old Data
Bit 3
Old Data
Bit 2
Old Data
Bit 1
Old Data
Bit 0
Don’t Care
Don’t Care
tSU(D)
SDI
OEN
LD
OUTN0
OUTN1
OUTN7
OUTN2
OUTN3
OUTN4
OUTN5
OUTN6
Off
On
Off
On
Off
On
Off
On
Off
On
Off
On
Off
On
Off
On
D6D7 D5 D4 D3 D2 D1 D0
1
2
3
4
5
6
7
Time = 0
CLK
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 10 - 24
AS1109
Datasheet - Detailed Description
Figure 14. Switching Global Error Mode Timing Diagram
8.3 Error-Detection Mode
Acquisition of the error status occurs at the rising edge of OEN. Error-detection mode is started on the rising edge of LD when OEN is high. The
CLK signal must be low when entering error detection mode. Error detection for open- and shorted-LEDs can only be performed for LEDs that
are switched on during test time. To switch between error-detection modes clock pulses are needed (see Table 5).
Note: To test all LEDs, a test pattern that turns on all LEDs must be input to the AS1109.
8.4 Global Error Mode
Global error mode is entered when error-detection mode is started. Clock pulses during this period are used to select between temperature,
open-LED, and shorted-LED tests, as well as low-current diagnostic mode and shutdown mode (see Table 5). In global error mode, an error flag
(TFLAG, OFLAG, SFLAG) is delivered to pin SDO if any errors are encountered.
Note: For a valid result SDI must be 1 for the first device.
If there are multiple AS1109s in a chain, the error flag will be gated through all devices. To get a valid result at the end of the chain, a logic 1 must
be applied to the SDI input of the first device of the chain. If one device produces an error this error will show up after n*t
P(I/O) + tSW(ERROR) at
pin SDO of the last device in the chain. This means it is not possible to identify which device in the chain produced the error. Therefore, if a global
error occurs, the detailed error report can be run to identify which AS1109, or LED produced the error.
Note: When no error has occurred, the detailed error report can be skipped, setting LD and subsequently OEN low.
Table 5. Global Error Mode Selections
Clock
Pulses
Output Port Error-Detection Mode Global Error Flag/Shutdown Condition
0 Don't Care Over-Temperature Detection
TFLAG = SDO = 1: No over-temperature warning.
T
FLAG = SDO = 0: Over-temperature warning.
1 Enabled Open-LED Detection
O
FLAG = SDO = 1: No open-LED error.
O
FLAG = SDO = 0: Open-LED error.
2 Enabled Shorted-LED Detection
S
FLAG = SDO = 1: No shorted-LED error.
S
FLAG = SDO = 0: Shorted-LED error.
3 Don't Care Low-Current Diagnostic Mode
4 Don't Care Shutdown Mode
SDI = 1: Wakeup
SDI = 0: Shutdown
tTESTING
tSU(ERROR)
OFLAG(IN) SFLAG(IN)TFLAG(IN)
TFLAG OFLAG SFLAG
tSW(ERROR)
SDI
OEN
LD
CLK
SDO
Acquisition of Error
Status
Don’t
Care
Don’t
Care
tGSW(ERROR)
tP(I/O)
tP4
tP(I/O) tP(I/O)
tSW(ERROR)
tGSW(ERROR)
tGSW(ERROR)
Don’t
Care
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 11 - 24
AS1109
Datasheet - Detailed Description
8.5 Error Detection Functions
8.5.1 Open-LED Detection
The AS1109 open-LED detection is based on the comparison between VDS and VTHL. The open LED status is aquired at the rising edge of
OEN and stored internally. While detecting open-LEDs the output port must be turned on. Open LED detection can be started with 1 clock pulse
during error detection mode while the output port is turned on.
Note: LEDs which are turned off at test time cannot be tested.
8.5.2 Shorted-LED
The AS1109 shorted-LED detection is based on the comparison between VDS and VTHH. The shortened LED status is acquired at the rising
edge of OEN and stored internally. While detecting shorted-LEDs the output port must be turned on. Shorted-LED detection can be started with
2 clock pulses during error detection mode while the output port is turned on.
For valid results, the voltage at OUTN0:OUTN7 must be lower then V
THH under low-current diagnostic mode operating conditions. This can be
achieved by reducing the VLED voltage or by adding additional diodes, resistors or LED’s.
Note: LEDs which are turned off at test time cannot be tested.
8.5.3 Overtemperature
Thermal protection for the AS1109 is provided by continuously monitoring the device’s core temperature. The overtemperature status is aquired
at the rising edge of OEN and stored internally.
Table 6. Open LED Detection Modes
Output Port State
Effective Output
Point Conditions
Detected Open-LED
Error Status Code
Meaning
On V
DS < VTHL 0 Open Circuit
On VDS > VTHL 1 Normal
Table 7. Shorted LED Detection Modes
Output Port State
Effective Output
Point Conditions
Detected Shorted-LED
Error Status Code
Meaning
On V
DS > VTHH 0 Short Circuit
On V
DS < VTHH 1 Normal
Table 8. Overtemperature Modes
Output Port State
Effective Output
Point Conditions
Detected Overtemperature
Status Code
Meaning
Don’t Care Temperature > T
OV1 0 Overtemperature Condition
Don’t Care Temperature < T
OV1 1Normal
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P25

AS1109-BSSU-Z

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ams
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LED Display Drivers AS1109-BSSU-Z QSOP16 LF TUB
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