- 您现在的位置：买卖IC网 > Datasheet目录307 > A8509GLPTR-T (Allegro Microsystems Inc)IC LED DVR WHITE 4X120MA 24TSSOP Datasheet资料下载
参数资料
| 型号： | A8509GLPTR-T |
| 厂商： | Allegro Microsystems Inc |
| 文件页数： | 21/28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 |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页当前第21页第22页第23页第24页第25页第26页第27页第28页
A8509
Wide Input Voltage Range, High Efficiency
4-Channel Fault Tolerant LED Driver
Design Example
This section provides a method for selecting component values
when designing an application using the A8509.
Assumptions: For the purposes of this example, the following are
given as the application requirements:
? V IN : 10 to 16 V
? Quantity of LED channels, #CHANNELS: 4
? Quantity of series LEDs per channel, #SERIESLEDS : 10
? LED current per channel, I LED : 240 mA
? V f(240) at 240 mA: 3.2 V (max)
? f SW : 600 kHz
? T A (max): 65°C
? PWM dimming frequency: 200 Hz, 1% duty cycle
Step 1: Connect LEDs to pins LED1 through LED4.
Electrical Characteristics table. Choose a value of resistor that is
the closest value higher than the calculated R OVP . In this design
example, a value of 750 k Ω is selected.
Below is the actual value of the minimum OVP trip level with the
selected resistor, applying equation 8:
V OVP(master) = R OVP × I OVPH + 1.25 V
= 750 k Ω × 49 μ A + 1.25 V
= 38.75 V
STEP 4: Determine the inductor. The inductor must be chosen
such that it can handle the necessary input current. In most appli-
cations, due to stringent EMI requirements, the inductor must
operate in continuous conduction mode throughout the whole
input voltage range.
STEP4a: Determine the maximum duty cycle of the system:
Step 2: Determine the LED current by setting resistor R ISET . To
do so, apply equation 2:
D (max) = 1–
V IN (min) × η
V OUT(OVP) + V f(boost)
(12)
= 1–
R ISET = (1.000 / I LED ) × 2320
= (1.000 V / 0.240 A ) × 2320
= 9.67 k Ω
Choose an 9.53 k Ω resistor.
STEP 3: Determine the OVP resistor. The OVP resistor is
connected between the OVP pin and the output voltage of the
converter. The first step is to determine the maximum voltage
based on the LED requirements. Then the regulation voltage of
650 mV should be added, along with 2 V for noise and regulation.
10 V × 0.9
34.65 V+ 0.4 V
= 74.5%
A good approximation of efficiency ( η ) is 90%. The voltage drop
of the boost diode can be approximated to be about 0.4 V.
STEP 4b: Determine the maximum and minimum input current
to the system. The minimum input current dictates the inductor
value. The maximum current rating dictates the current rating of
the inductor.
V OUT(OVP)(min) – V OVP(th) (min)
R OVP =
=
I IN (max) =
=
Given the regulation voltage (V LED ) of theA8509 is 650 mV, the
minimum required voltage can be determined as follows:
V OUT(OVP) = #SERIESLEDS × V f(240) + V LED + 2 V (10)
= 10 × 3.2 V + 0.650 V + 2 V
V OUT(OVP)(min) = 34.65 V
The OVP resistor (ROVP) value can be calculated as:
(11)
I OVPH (min)
34.65 V – 1.11 V
45 μ A
= 745 k Ω
where both I OVP(th) (min) and V OVP(th) (min) are found in the
To calculate the maximum input current, first determine the
required output current:
I OUT = #CHANNELS × I LED
= 4 × 240 mA
= 0.960 A
Then substitute into the formula for maximum input current:
V OUT × I OUT
V IN (min) × η
34.65 V × 0.960 A
10 V × 0.90
= 3.7 A
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
(13)
(14)
21
相关PDF资料 |
PDF描述 |
|---|---|
| A8510GECTR-T | IC LED DRVR BCKLGHT/WHT 26QFN-EC |
| A8511KLPTR-T | IC LED DVR 150MA AUTO 28-TSSOP |
| A8512ELBTR-T | IC LED DVR WHT/RGB BKLGT 24SOIC |
| A8513KLPTR-T | IC LED DRVR AUTO BCKLGHT 16TSSOP |
| A8514KLPTR-T | IC LED DVR WHT 4X80MA 16-ETSSOP |
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 |
发布紧急采购，3分钟左右您将得到回复。