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| 型号： | MAX16812ATI+ |
| 厂商： | Maxim Integrated |
| 文件页数： | 10/21页 |
| 文件大小： | 0K |
| 描述： | IC LED DRIVR HIGH BRIGHT 28-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 60 |
| 恒定电流： | 是 |
| 拓扑： | PWM，SEPIC，降压（降压），升压（升压） |
| 输出数： | 1 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 车载 |
| 类型 - 次要： | 高亮度 LED（HBLED） |
| 频率： | 125kHz ~ 500kHz |
| 电源电压： | 5.5 V ~ 76 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-WFQFN 裸露焊盘 |
| 供应商设备封装： | 28-TQFN-EP（5x5） |
| 包装： | 托盘 |
| 工作温度： | -40°C ~ 125°C |
| 产品目录页面： | 1425 (CN2011-ZH PDF) |
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
Undervoltage Lockout
The MAX16812 features an adjustable UVLO through
the enable input (EN). Connect EN directly to IN to use
the 5V default UVLO. Connect EN to IN through a resis-
tive divider to ground to set the UVLO threshold. The
minimizing output-voltage overshoot. While the part is in
UVLO, C REF is discharged (Figure 3). Upon coming out
of UVLO, an internal current source starts charging C REF
during the soft-start cycle. Use the following equation to
calculate total soft-start time:
MAX16812 is enabled when V EN exceeds the 1.38V
(typ) threshold.
Calculate the EN UVLO resistor-divider values as fol-
lows (see Figure 2):
t ST = C REF ×
1.238
I REF
R UV1 = R UV2 x ?
? V UVLO - V EN ?
? V EN ?
?
where R UV1 is in the 20k Ω range, V EN is the 1.38V (typ)
EN threshold voltage, and V UVLO is the desired input-
voltage UVLO threshold in volts. Due to the 100mV hys-
teresis of the UVLO threshold, capacitor C EN is
required to prevent chattering at the UVLO threshold
due to line impedance drops at power-up and during
dimming. If the undervoltage setting is very close to the
required minimum operating voltage, there can be
jumps in the voltage at IN while dimming. C EN should
be large enough to limit the ripple on EN to less than
100mV (EN hysteresis) under these conditions so that it
does not turn on and off due to the ripple on IN.
Soft-Start
The soft-start feature of the MAX16812 allows the LED
string current to ramp up in a controlled manner, thus
V IN
IN
R UV2
MAX16812
EN
where I REF is 40μA, C REF is in μF, and t ST is in sec-
onds. Operation begins when REF ramps above 0.6V.
Once the soft-start is complete, REF is regulated to
1.238V, the internal voltage reference.
Low-Side Internal
Switching MOSFET Driver Supply (L_REG)
L_REG is the regulated (5.2V) internal supply voltage
capable of delivering 20mA. L_REG provides power to
the gate drive of the internal switching power MOSFET.
V L_REG is referenced to AGND. Connect a 3.3μF
ceramic capacitor from L_REG to AGND.
High-Side Regulator (H_REG)
H_REG is a low-dropout linear regulator referenced to
LV. H_REG provides the gate drive for the external
n-channel dimming MOSFET and also powers up the
MAX16812 ’s LED current-sense circuitry. Bypass
H_REG to LV with a 1μF ceramic capacitor.
V IN
IN
MAX16812
REF
C EN
R UV1
C REF
Figure 2. UVLO Threshold Setting
AGND
Figure 3. Soft-Start Setting
AGND
10
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX16812ATI/V+ | 功能描述:LED照明驱动器 w/Analog & PWM Dimming Control 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 |
| MAX16812ATI/V+T | 功能描述:LED照明驱动器 w/Analog & PWM Dimming Control 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 |
| MAX16812ATI+ | 功能描述:LED照明驱动器 w/Analog & PWM Dimming Control 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 |
| MAX16812ATI+T | 功能描述:LED照明驱动器 w/Analog & PWM Dimming Control 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 |
| MAX16812EVKIT+ | 功能描述:LED 照明开发工具 Evaluation Kit for the MAX16812 RoHS:否 制造商:Fairchild Semiconductor 产品:Evaluation Kits 用于:FL7732 核心: 电源电压:120V 系列: 封装: |
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