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参数资料
| 型号： | MAX16841ASA+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 10/18页 |
| 文件大小： | 0K |
| 描述： | IC LED DRVR DIM OFFLINE |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 拓扑： | 交直流离线开关，回扫，降压（降压） |
| 输出数： | 1 |
| 内部驱动器： | 无 |
| 类型 - 主要： | 通用 |
| 频率： | 50kHz ~ 300kHz |
| 电源电压： | 11 V ~ 20 V |
| 输出电压： | 20V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 供应商设备封装： | 8-SOIC（窄型） |
| 包装： | 带卷 (TR) |
| 工作温度： | -40°C ~ 125°C |
MAX16841
Controller IC for Dimmable Offline LED Lamps
P IN = OUT
I IN = IN
V = 2 × V INrms
R16 = IN
R CS = CS
0.8 × V DSmax ? V INmax
N PS =
V LED
I Lmax = OUT
( 2 × V INmax ? V LED ) × D
N AS =
Resistors R16 and R20
The average current in resistor R16 is the average input
current of the buck converter.
If P OUT is the output power, then the input power is given by:
P
η
P ×π
2 × V M
M
I × R20 + 0.1V
10μA
V × 80%
IL P
=
I LP I IN + 0.5 × ? I Lmax
I LP is the switch peak current. Maximum peak in the
switch current occurs at the peak level of the highest
input voltage.
V CS is 2.2V. Allow 80% margin for tolerances.
Inductor Selection
For optimum efficiency, inductor L5 must be operated in
continuous-conduction mode.
The current in the inductor would be at its maximum level
at peak of the highest input voltage. LED string voltage
is assumed constant. Calculate the duty cycle at peak of
the highest input voltage.
D =
2 × V INmax
The percentage peak-to-peak ripple is considered
between 30% and 60% of the inductor current. Assuming
60% peak-to-peak inductor current ripple, the maximum
inductor current is given by:
P ×π
2 × V LED
The minimum value of the inductor is given by:
Lmin =
0.6 × I Lmax × f SW
Maxim Integrated
Figure 2 shows a PFC triac, dimmable, isolated (flyback
topology) offline LED driver.
Here the current through the Q4 MOSFET is controlled.
Current through Q4 is the same as the input current
of the flyback converter. The input-side circuitry is the
same as in the nonisolated buck LED driver that was
previously described. During startup, the device is
powered up from Q2, R10, R11, and D8. Bootstrap from
the bias winding on the transformer turns off the Q2
MOSFET, thus saving power from high-voltage line. Here
the switching threshold programmed by R15, R16, and
R18 can be lower than the LED string voltage.
Output-side electrolytic capacitors C8 and C9 are used
for filtering the double-line frequency current ripple in
LED current.
During an open LED condition, the voltage across the
output capacitors increases and is reflected on the bias-
winding side.
Once the bias-winding voltage goes above 22.5V (typ),
NDRV is disabled and the Q4 MOSFET turns off.
Choose the transformer turns ratio based on the voltage
rating of the MOSFET. Use the following expression to
calculate primary-secondary turns ratio:
V LEDmax
where:
N PS is the primary-secondary turns ratio
V DSmax is the voltage rating of the Q4 MOSFET
V INmax is the maximum peak input voltage
V LEDmax is the maximum voltage of the LED string
Factor 0.8 is taken into account for the voltage spikes,
due to transformer-leakage inductance.
Use the following equation to calculate bias-secondary
turns ratio:
18V
V LEDmax
where N AS is the bias-secondary turns ratio and 18V is
the bias voltage for the device.
10
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相关代理商/技术参数 |
参数描述 |
|---|---|
| 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: |
| MAX16841EVKIT# | 功能描述:LED 照明开发工具 MAX16841 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: |
| MAX16841EVKIT+ | 功能描述:LED 照明开发工具 MAX16841 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: |
| MAX16842ASA+ | 功能描述:模数转换器 - ADC New RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| MAX16842ASA+T | 功能描述:模数转换器 - ADC New RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
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