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参数资料
| 型号： | A8508GLPTR-T |
| 厂商： | Allegro Microsystems Inc |
| 文件页数： | 12/28页 |
| 文件大小： | 0K |
| 描述： | IC LED DVR WHITE 8X120MA 24TSSOP |
| 标准包装： | 8,000 |
| 拓扑： | PWM，SEPIC，升压（升压） |
| 输出数： | 8 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 背光 |
| 类型 - 次要： | 白色 LED |
| 频率： | 300kHz ~ 800kHz |
| 电源电压： | 9 V ~ 40 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 24-TSSOP（0.173"，4.40mm）裸露焊盘 |
| 供应商设备封装： | 24-TSSOP 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 工作温度： | -40°C ~ 105°C |
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A8508
Wide Input Voltage Range, High Efficiency
8-Channel Fault Tolerant LED Driver
The cited values are for 1% tolerance resistors. If the calculated
value was not present, the next lowest value of 1% resistor was
chosen.
PWM dimming
Applying an external PWM signal on the PWM pin performs
C1
V OUT
I OUT
PWM dimming. When the PWM pin is pulled high, the A8508
enables the LEDx pins to sink 100% current. When PWM is
pulled low, the boost converter and LEDx sinks are turned off.
The compensation (COMP) pin is floated, and critical internal
circuits are kept active.
C2
C3
C4
V COMP
V PWM
The typical PWM dimming frequencies fall between 100 and
1000 Hz. Figures 15 and 16 show examples of dimming at 50%
and 0.5% duty cycles.
Analog dimming
The A8508 can also be dimmed by using an external DAC or
other voltage source applied either directly to the ground side
of the RISET resistor or through an external resistor to the ISET
pin (see figure 17). The ISET current can be varied in the range
between 34 μ A and 130 μ A.
t
Figure 15. PWM dimming: f SW = 200 Hz, 50% duty cycle, V OUT = 30 V,
V IN = 12 V, and I LED = 120 mA per LED string; shows V OUT (ch1,
10 V/div.), I OUT (ch2, 500 mA/div.), V COMP (ch3, 2 V/div.), and PWM (ch4,
5 V/div.), t = 2 ms/div.
V OUT
C1
? For a single-resistor configuration (panel A of figure 17), the
ISET current is controlled by the following formula:
C2
I OUT
R ISET
V ISET – V DAC
I SET = (3)
where V ISET is the ISET pin voltage and V DAC is the DAC output
voltage.
? For a dual-resistor configuration (panel B of figure 17), the
ISET current is controlled by the following formula:
C3 V COMP
C4
V PWM
t
Figure 16. PWM dimming: f SW = 200 Hz, 0.5% duty cycle, V OUT = 30 V,
V IN = 15 V, I LED = 120 mA per LED string; shows V OUT (ch1, 10 V/div.),
I OUT (ch2, 500 mA/div.), V COMP (ch3, 2 V/div.), and V PWM (ch4, 5 V/div.),
t = 10 μ s/div.
I SET =
V ISET
R ISET
–
V DAC – V ISET
R 1
(4)
DAC
VDAC
R ISET
A8508
ISET
The advantage of this circuit is that the DAC voltage can be
higher or lower, thus adjusting the LED current to a higher or
lower value of the preset LED current set by the R ISET resistor:
GND
DAC
R1
A
GND
A8508
? V DAC = 1.00 V: output is strictly controlled by R ISET
? V DAC > 1.00 V: LED current is reduced
? V DAC < 1.00 V: LED current is increased
VDAC
GND
R ISET
B
ISET
GND
Figure 17. Typical application simplified diagram of voltage LED current
control using a DAC to control LED current.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
12
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相关代理商/技术参数 |
参数描述 |
|---|---|
| A8509 | 制造商:ROCKWE 功能描述: |
| A8509GLPTR-T | 功能描述:IC LED DVR WHITE 4X120MA 24TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 拓扑:升压（升压），切换式电容器（充电泵） 输出数:1 内部驱动器:是 类型 - 主要:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽） 供应商设备封装:10-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C |
| A8510 | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:Wide Input Voltage Range, High Efficiency |
| A8510GECTR-T | 功能描述:IC LED DRVR BCKLGHT/WHT 26QFN-EC RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 特色产品:LM3445 TRIAC Dimmable LED Driver 标准包装:55 系列:PowerWise® 恒定电流:是 恒定电压:- 拓扑:PWM，降压（降压） 输出数:1 内部驱动器:无 类型 - 主要:- 类型 - 次要:高亮度 LED（HBLED） 频率:30kHz ~ 1MHz 电源电压:8 V ~ 12 V 输出电压:- 安装类型:表面贴装 封装/外壳:14-SOIC（0.154"，3.90mm 宽） 供应商设备封装:14-SOICN 包装:管件 工作温度:-40°C ~ 125°C 产品目录页面:1285 (CN2011-ZH PDF) 其它名称:LM3445M |
| A8511 | 制造商:ROCKWE 功能描述: |
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