- 您现在的位置：买卖IC网 > Datasheet目录310 > AL8400SE-7 (Diodes Inc)IC CTRLR LED DRIVER SOT353 Datasheet资料下载
参数资料
| 型号： | AL8400SE-7 |
| 厂商： | Diodes Inc |
| 文件页数： | 9/13页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR LED DRIVER SOT353 |
| 标准包装： | 1 |
| 拓扑： | 线性 |
| 输出数： | 1 |
| 内部驱动器： | 无 |
| 类型 - 主要： | 通用 |
| 电源电压： | 2.2 V ~ 18 V |
| 输出电压： | 0.2 V ~ 18 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 6-TSSOP（5 引线），SC-88A，SOT-353 |
| 供应商设备封装： | SOT-353 |
| 包装： | 标准包装 |
| 工作温度： | -40°C ~ 125°C |
| 其它名称： | AL8400SE-7DIDKR |
AL8400 /AL8400Q
Application Information (cont.)
N-Channel MOSFET as the Pass Element (cont.)
The equations (1 and 2) for the bipolar transistor are transformed into:
LED circuit path:
5 .
V CC = (V LED + V DS + V FB )
where VFB is approximately the internal reference voltage of 200mV.
Control drive circuit path
6 .
V CC
= (V RB + V GS + V FB )
The maximum total LED voltage plus the reference voltage determines the minimum supply voltage. Substituting into equation 5 yields:
V CC min = V LED + V DSMIN + V FB
The MOSFET DC gate current is negligible, so the bias resistor R B has only to provide the minimum output current of the AL8400. So
rearranging equation 6 yields the boundaries for allowable R B values:
7 .
R B min =
V CC max ? V GS min ? V FB
I OUT max
8 .
R B max =
V CC min ? V GS max ? V FB
I OUT min
Where I OUTmax is the AL8400 maximum output current
Where I OUTmin is the AL8400 minimum output current
Once the value of R B has been determined, somewhere between R Bmax and R Bmin – trying to get I OUT close to 1mA for all variations, the value for
compensation capacitor, C L , should be calculated.
The MOSFET selection is also influenced by the maximum power dissipation
P TOT = I LED * (V CC – V LED – V FB ) = I LED * V DS
Since this determines the package choice ( θ JA ) in order to keep the junction temperature below the maximum value allowed.
T J = T A + P TOT ? θ JA
where
T J(MAX) is the maximum operating junction temperature,
T A is the ambient temperature,
θ JA is the junction to ambient thermal resistance.
Low Supply Voltages and MOSFET as Pass Element
When driving a single LED at low supply voltages, a low threshold MOSFET or high gain NPN bipolar transistor should be used as the LED driving
pass transistor.
This is because a standard threshold voltage MOSFET might not have enough Gate-Source voltage to ensure that it is sufficiently enhanced to
regulate the LED current.
MOSFET Example Choosing R B and C L
The driver is required to control 3 series connected LEDs at 200mA ±10% from an 12V ±5% supply. Each LED has a forward voltage of 3V
minimum and of 3.6V maximum.
Therefore the minimum supply voltage is 11.4V and the maximum LED chain voltage is 10.8V.
Rearranging equation 5 (page 9); the minimum voltage drop across the MOSFET is required to be:
I LED × R DS = V CC min ? V LED max ? V FB =
= 11 . 4 V ? 10 . 8 V ? 0 . 2 V = 0.4V
R DS(ON) ≤ 2 ?
We will use the DMN6068SE N-channel MOSFET (Q2) with a maximum R DS(ON) of 100m ? at V GS = 4.5V.
AL8400/ AL8400Q
Document number: DS35115 Rev. 4 - 2
9 of 13
www.diodes.com
August 2012
? Diodes Incorporated
相关PDF资料 |
PDF描述 |
|---|---|
| AL8805W5-7 | IC REG SW CONV BUCK ASYNC SOT-23 |
| AL8806MP8-13 | IC LED DVR CONS CURR 8MSOP |
| AL8807W5-7 | IC LED DRVR DCDC BUCK SOT25 |
| AL9910AS-13 | IC LED DRVR HIGH BRIGHT SO8EP |
| ALC60481R05 | PWR SUP AC-DC 6-48V 1.05A 50.4W |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AL841B | 制造商:ELC 功能描述:PSU BENCH MULTI OUTPUT 制造商:ELC 功能描述:PSU, BENCH, MULTI OUTPUT, EURO |
| AL8504 | 制造商:Molex 功能描述: |
| AL-85-120VAC | 制造商:Carlo Gavazzi 功能描述:LATCH UNIT 50-85A |
| AL875 | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Triple High Speed, 8-bit Analog-to-Digital Converter |
| AL8805 | 制造商:DIODES 制造商全称:Diodes Incorporated 功能描述:HIGH EFFICIENCY 30V 1A BUCK LED DRIVER |
发布紧急采购，3分钟左右您将得到回复。