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参数资料
| 型号： | AS1109 EB |
| 厂商： | ams |
| 文件页数： | 19/25页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL AS1109 |
| 标准包装： | 1 |
| 电流 - 输出 / 通道： | 0.5 ~ 100 mA |
| 输出及类型： | 8，非隔离 |
| 输出电压： | 0 ~ 15 V |
| 特点： | 过热保护，开路 LED，短路 LED，诊断 |
| 输入电压： | 3 ~ 5.5 V |
| 已供物品： | 板 |
| 已用 IC / 零件： | AS1109 |
AS1109
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
9.2 Cascading Devices
To cascade multiple AS1109 devices, pin SDO must be connected to pin SDI of the next AS1109 (see Figure 23) . At each rising edge of CLK the
LSB of the shift register will be written into the shift register SDI of the next AS1109 in the chain. Data at the SDI pin is clocked in at the rising
edge of the CLK pulse and is clocked out at the SDO pin 8.5 clock cycles later at the falling edge of the CLK pulse.
Note: When n *AS1109 devices are in one chain, n *8 clock pulses are needed to latch-in the input data.
Figure 23. Cascading AS1109 Devices
SDI
SDI
AS1109 #1
CLK
LD
SDO
OEN
SDI
AS1109 #2
CLK
LD
SDO
OEN
SDI
AS1109 # n -1
CLK
LD
SDO
OEN
CLK
LD
OEN
9.3 Constant Current
In LED display applications, the AS1109 provides virtually no current variations from channel-to-channel and from AS1109-to-AS1109. This is
mostly due to 2 factors:
?? While I OUT ≥ 50mA, the maximum current skew is less than ±2% between channels and less than ±2% between AS1109 devices.
?? In the saturation region, the characteristics curve of the output stage is flat
constant regardless of the variations of LED forward voltages (V F ).
9.4 Adjusting Output Current
The AS1109 scales up the reference current (I REF ) set by external resistor (R EXT ) to sink a current (I OUT ) at each output port. As shown in
Figure 3 on page 6 the output current in the saturation region is extremely flat so that it is possible to define it as target current (I OUT TARGET ).
I OUT TARGET can be calculated by:
V REXT = 1.253V
I REF = V REXT /R EXT (if the other end of R EXT is connected to ground)
I OUT TARGET = I REF *15 = (1.253V/R EXT )*15
(EQ 1)
(EQ 2)
(EQ 3)
Where:
R EXT is the resistance of the external resistor connected to pin REXT.
V REXT is the voltage on pin REXT.
The magnitude of current (as a function of R EXT ) is around 100mA at 186 Ω , 50.52mA at 372 Ω and 25.26mA at 744 Ω . Figure 3 on page 6
shows the relationship curve between the I OUT TARGET of each channel and the corresponding external resistor (R EXT ).
Revision 1.21
18 - 24
相关PDF资料 |
PDF描述 |
|---|---|
| AS1110 EB | BOARD EVAL AS1110 |
| AS1112 EB | BOARD EVAL AS1112 |
| AS1115 DB-YELLOW | BOARD DEMO AS1115 YELLOW |
| AS1116 DB-YELLOW | BOARD DEMO AS1116 YELLOW |
| AS3691A EB | BOARD EVAL AS3691A |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AS1109-QF_EK_ST | 功能描述:AS1109 8, Non-Isolated Output LED Driver Evaluation Board 制造商:ams 系列:- 零件状态:有效 电流 - 输出/通道:100mA 输出和类型:8，非隔离 电压 - 输出:15V 特性:过热保护，开路 LED，短路 LED，诊断 电压 - 输入:3 V ~ 5.5 V 所含物品:板 使用的 IC/零件:AS1109 标准包装:1 |
| AS110R0JLF | 制造商:TT Electronics / IRC 功能描述:AS110R0JLF |
| AS110R2FLF | 制造商:TT Electronics / IRC 功能描述:AS110R2FLF |
| AS110R2HLF | 制造商:TT Electronics / IRC 功能描述:AS110R2HLF |
| AS110R2JLF | 制造商:TT Electronics / IRC 功能描述:AS110R2JLF |
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