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| 型号： | A8509GLPTR-T |
| 厂商： | Allegro Microsystems Inc |
| 文件页数： | 19/28页 |
| 文件大小： | 0K |
| 描述： | IC LED DVR WHITE 4X120MA 24TSSOP |
| 标准包装： | 8,000 |
| 拓扑： | PWM，SEPIC，升压（升压） |
| 输出数： | 4 |
| 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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A8509
Wide Input Voltage Range, High Efficiency
4-Channel Fault Tolerant LED Driver
Application Information
V OUT(OVP) – 1.25 V
Paralleling more than oneA8509
The A8509 can be paralleled together by using a single boost
converter (master) to provide output power for up to a total of
four A8509s (slaves). The MODE pin of each device must be tied
to the VDD pin of the same device for proper mode selection.
In this mode, the ˉF ˉAˉ ˉUˉ ˉLˉ ˉTˉ pins and the COMP pins become a bi-
direction signal bus for the system to communicate.
At initial power-up, each IC will release a pull-down resistor
on the COMP pin and start in soft start mode. When 200 mV is
detected on the COMP pin, the master will then switch to normal
mode. Also, for proper operation all of the ˉF ˉAˉ ˉUˉ ˉLˉ ˉTˉ pins must be
tied together to prevent the parallel ICs from powering-up into
a shorted LEDx pin situation. While the ˉF ˉAˉ ˉUˉ ˉLˉ ˉTˉ pins are pulled
limit and never decrease the output voltage to the lower regula-
tion level.
The required slave OVP resistor value can be calculated using the
following formula:
R OVP(slave) = (7)
I OVPH (min)
where V OUT(OVP) is the required OVP voltage level, and
I OVPH (min) is the current into the OVP pin found in the Electrical
Characteristics table. The minimum value should be used in this
calculation.
The required master OVP voltage level can be calculated using
the following formula:
low, the system will not proceed with start-up.
Below is a simple list of necessary connections for the master,
V OVP(master) = R OVP(slave) × I OVPH (max) + 1.25 V
(8)
V OVP(master) – 1.25 V
to ensure proper parallel operation (refer toApplication C in the
Typical Applications section):
? COMP pin
? VOUT node
? ˉF ˉAˉ ˉUˉ ˉLˉ ˉTˉ pin
? EN pin
? PWM pin
Each one of these must be connected to the corresponding signal
on the slave devices.
OVP setting for parallel operation
A notable exception to the list is the OVP pin. In this system
each OVP pin must be set with a dedicated resistor. To make sure
that the system will operate properly, the overvoltage protection
on the master IC should be set higher than on the slave IC. The
A8509 checks open LED condition upon hitting the OVP voltage.
If the master OVP voltage is set lower than the slave OVP, the
slave OVP pin will not trip to permit the open LED check. This in
turn will not remove the corresponding LEDx pins from regula-
tion. Therfore, the output voltage will stay at the master OVP
where V OVP(master) is the minimum minimum OVP voltage level
of the master IC, I OVPH (max) is current into the OVP pin found in
the Electrical Characteristics table. The maximum value should
be used in this calculation.
The required master OVP resistor value can be calculated using
the following formula:
R OVP(master) = (9)
I OVPH (min)
where V OVP(master) is the minimum required master OVP voltage
level, and I OVPH (min) is the current into the OVP pin found in the
Electrical Characteristics table. The minimum value should be
used in this calculation.
Following the above formulas will guarantee that there is no
overlap in OVP voltage levels in the system. All slave A8509s
in the system can have the same OVP voltage setting. Figure 32
shows a proper master-slave OVP setting, and figure 33 shows
the result of setting the master OVP too low.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
19
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相关代理商/技术参数 |
参数描述 |
|---|---|
| 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: |
| A8511KLPTR-T | 功能描述:IC LED DVR 150MA AUTO 28-TSSOP 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 |
| A8512 | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:LED Backlight Driver for Medium/Large Displays |
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