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参数资料
| 型号： | MAX16840EVKIT+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 9/12页 |
| 文件大小： | 0K |
| 描述： | KIT EVAL FOR MAX16840 LED DVR |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 5 |
| 输出及类型： | 1，非隔离 |
| 特点： | 可调光 |
| 已供物品： | 板 |
| 已用 IC / 零件： | MAX16840 |
MAX16840
LED Driver with Integrated MOSFET
for MR16 and Other 12V AC Input Lamps
R3
L2
DRAIN
D1
LED+
L1
BD1
REFI
IN
12V AC
C1
EXT
COMP
MAX16840
SOURCE
C3
LED-
C4
R2
GND
FB
R1
Figure 2. Boost LED Driver
D MIN = 1 ?
= 1 ?
Applications information
Boost Configuration
In MR16 and other 12V AC input applications, the boost
configuration is used when the LED string voltage
exceeds 18V. This means that, in general, if the number
of LEDs in series in the application is greater than or
equal to 6 LEDs, the IC can be used in the boost con-
figuration to provide the best efficiency. Figure 2 shows a
boost MR16 application. The number of LEDs can range
from 6 to 10 LEDs. The maximum voltage across the LED
string should not exceed 40V.
In the boost configuration, the current in the inductor is
the same as the current in the current-sense resistor R1.
Resistor (R1)
The current in resistor R1 is the same as the current in
inductor L2. If the desired maximum output power with
12V AC at 50Hz or 60Hz is P OUT , the input power P IN is
given:
P IN = P OUT / n
peak current in the inductor occurs at the peak of the
highest input voltage. The P-P ripple at this input voltage
is ?I L . The highest input voltage is 13.2V AC, which is
10% higher than the typical value.
The peak current in the inductor is:
I PK = I IN + 0.5?I L
The output voltage of the LED string is given by V LED . As
a first-order approximation, the LED voltage is assumed
constant. The duty cycle at the peak of the input voltage
is therefore:
13.2V × 2 18.66V
V LED V LED
The percentage P-P ripple is typically selected in the 30%
to 60% range of the maximum input current. Assuming
a 60% P-P inductor-current ripple, the maximum inductor
current is given by:
I PK = 1.3I INMAX
The minimum inductor value is given by:
where n is the efficiency. The input current is given by:
I IN = P IN /10.8V
L MIN =
18.66V × D MIN
0.6I INMAX × 300kHz
Resistor R1 is then given by:
R1 = 0.2V/I IN
where R1 is in ohms and I IN is in amps.
Boost Inductor (L2)
For optimum efficiency, the boost inductor must be oper-
ating in continuous-conduction mode. The maximum
Maxim Integrated
where the switching frequency is 300kHz. The saturation
current of the inductor should be higher than P-P and the
minimum value of the inductor at I P-P should exceed L MIN .
The temperature of the inductor can be in the +90 N C to
+100 N C range in the application and the losses should
be estimated at these elevated temperatures.
9
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| MAX16840EVKIT# | 功能描述:LED 照明开发工具 MAX16840 Eval Kit 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: |
| MAX16840EVKIT+ | 功能描述:LED 照明开发工具 MAX16840 Eval Kit 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: |
| MAX16841ASA+ | 功能描述:LED照明驱动器 Wide Input Offline w/Dimming 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 |
| MAX16841ASA+T | 功能描述:LED照明驱动器 Wide Input Offline w/Dimming 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 |
| MAX16841BEVKIT# | 功能描述:LED 照明开发工具 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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