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参数资料
| 型号： | MIC3287-24YML TR |
| 厂商： | Micrel Inc |
| 文件页数： | 7/9页 |
| 文件大小： | 0K |
| 描述： | IC LED DRIVER WHITE BCKLGT 8-MLF |
| 标准包装： | 1 |
| 恒定电流： | 是 |
| 拓扑： | PWM，升压（升压） |
| 输出数： | 1 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 背光，闪灯/白光 |
| 类型 - 次要： | 白色 LED |
| 频率： | 1MHz ~ 1.4MHz |
| 电源电压： | 2.8 V ~ 6.5 V |
| 输出电压： | 36V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-VFDFN 裸露焊盘，8-MLF? |
| 供应商设备封装： | 8-MLF?（2x2） |
| 包装： | 标准包装 |
| 工作温度： | -40°C ~ 125°C |
| 产品目录页面： | 1082 (CN2011-ZH PDF) |
| 其它名称： | 576-1464-6 |
Micrel, Inc
Dimming Control
There are two techniques for dimming control. One is PWM
dimming, and the other is continuous dimming.
1. PWM dimming control is implemented by applying
a PWM signal to the EN pin, as shown in Figure
1. The MIC3287 is turned on and off by the PWM
signal. With this method, the LEDs operate with
either zero or full current. The average LED current
is increased proportionally to the duty-cycle of the
PWM signal. This technique has high-efficiency
because the IC and the LEDs consume no current
during the off time of the PWM signal. Typical PWM
frequency should be between 100Hz and 10kHz.
2. Continuous dimming control is implemented by
applying a DC control voltage to the FB pin of
the MIC3287 through a series resistor, as shown
in Figure 2. The LED intensity (current) can be
dynamically varied with the applied DC control
voltage. The DC voltage can come from a DAC
signal, or a filtered PWM signal. The advantage
of the filtered PWM signal approach is a high
frequency PWM signal (>10kHz) can be used to
control LED intensity (current).
MIC3287
Open-Circuit Protection
If the LEDs are disconnected from the circuit, or in the case
that an LED fails, the sense resistor will then pull the FB pin to
ground. This will cause the MIC3287 to switch with a high duty-
cycle, resulting in output over-voltage. This may cause the SW
pin voltage to exceed its maximum voltage rating, damaging
the IC and the external components. To ensure the highest
level of protection, the MIC3287 has buit-in 24V over-voltage
protection functionality in the TSOT-23-6 pin and 8-pin MLF?
package options. The OVP will clamp the output voltage to
within the specified limits.
Start-Up and Inrush Current
If the inrush current needs to be limited, a soft-start circuit, simi-
lar to Figure 3, could be implemented. The soft-start capacitor,
C SS , provides overdrive to the FB pin at start-up, resulting in
gradual increase of switch duty cycle and limited in rush current.
V IN
C SS
2200pF
VIN SW
EN FB
V IN
GND
R
10k
VIN
SW
Figure 3. Soft-Start Circuit
PWM
EN
FB
GND
Figure 1. PWM Dimming Method
V IN
VIN
SW
EN
GND
FB
5.11k
49.9k
DC?
Equivalent
Figure 2. Continuous Dimming
April 2010
7
M9999-042910
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MIC3287YD5 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:1.2MHz PWM White LED Driver with OVP in Thin SOT-23 and 2mm x 2mm MFL |
| MIC3287YD5 TR | 功能描述:LED照明驱动器 2x2mm White LED Driver w/ 24V OVP (Lead Free) RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N |
| MIC3287YD5-TR | 功能描述:LED 驱动器 IC 1 输出 DC DC 稳压器 升压（升压） 模拟，PWM 调光 350mA（开关） TSOT-23-5 制造商:microchip technology 系列:- 包装:剪切带（CT） 零件状态:停产 类型:DC DC 稳压器 拓扑:升压（升压） 内部开关:是 输出数:1 电压 - 供电（最低）:2.8V 电压 -?供电（最高）:6.5V 电压 - 输出:36V 电流 - 输出/通道:350mA（开关） 频率:1.2MHz 调光:模拟，PWM 应用:背光 工作温度:-40°C ~ 125°C （TJ） 安装类型:表面贴装 封装/外壳:SOT-23-5 细型，TSOT-23-5 供应商器件封装:TSOT-23-5 标准包装:1 |
| MIC3289 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:1.2MHz PWM White LED Driver with Internal Schottky Diode and True 1-Wire Digital Control |
| MIC3289_0706 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:1.2MHz PWM White LED Driver with Internal Schottky Diode and True 1-Wire Digital Control |
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