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| 型号： | MAX17061ETI+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 23/26页 |
| 文件大小： | 0K |
| 描述： | IC LED DRVR WHITE BCKLGT 28-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 拓扑： | PWM，升压（升压） |
| 输出数： | 8 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 车载，背光 |
| 类型 - 次要： | 白色 LED |
| 频率： | 1MHz |
| 电源电压： | 4.5 V ~ 26 V |
| 输出电压： | 5V |
| 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（4x4） |
| 包装： | 带卷 (TR) |
| 工作温度： | -40°C ~ 85°C |
8-String White LED Driver with
SMBus for LCD Panel Applications
LED Selection and Bias
The series/parallel configuration of the LED load and the
full-scale bias current have a significant effect or regula-
tor performance. LED characteristics vary significantly
from manufacturer to manufacturer. Consult the respec-
tive LED data sheets to determine the range of output
voltages for a given brightness and LED current. In gen-
eral, brightness increases as a function of bias current.
This suggests that the number of LEDs could be
decreased if higher bias current is chosen; however,
high current increases LED temperature and reduces
operating life. Improvements in LED technology are
resulting in devices with lower forward voltage and
while increasing the bias current and light output.
LED manufacturers specify LED color at a given LED
current. With lower LED current, the color of the emitted
light tends to shift toward the blue range of the spec-
trum. A blue bias is often acceptable for business appli-
cations but not for high-image-quality applications such
as DVD players. Direct DPWM dimming is a viable solu-
tion for reducing power dissipation while maintaining
LED color integrity. Careful attention should be paid to
switching noise to avoid other display quality problems.
Using fewer LEDs in a string improves step-up converter
efficiency, and lowers breakdown voltage requirements
of the external MOSFET and diode. The minimum num-
ber of LEDs in series should always be greater than
maximum input voltage. If the diode voltage drop is
lower than maximum input voltage, the voltage drop
across the current-sense inputs (FB_) increases and
causes excess heating in the IC. Between 8 and 12
LEDs in series are ideal for input voltages up to 20V.
Applications Information
LED V FB_ Variation
The MAX17061 has accurate (±1.5%) matching for
each current source. However, the forward voltage of
each white LED can vary up to 25% from part to part.
The accumulated voltage difference in each string
equates to additional power loss within the IC. For the
best efficiency, the voltage difference between strings
should be minimized. The difference between lowest
voltage string and highest voltage string should be less
than 4.8V (typ). Otherwise, the internal LED short-
protection circuit disables the high FB string.
FB Pin Maximum Voltage
The current through each FB_ pin is controlled only
during the step-up converter’s on-time. During the con-
verter’s off-time, the current sources are turned off. The
output voltage does not discharge and stays high. The
MAX17061 disables the FB current source to which the
string is shorted. In this case, the step-up converter’s
output voltage is always applied to the disabled FB pin.
The FB_ pin can withstand 45V.
PCB Layout Guidelines
Careful PCB layout is important for proper operation.
Use the following guidelines for good PCB layout:
1) Minimize the area of high current switching loop of
rectifier diode, internal MOSFET, and output capac-
itor to avoid excessive switching noise.
2) Connect high-current input and output components
with short and wide connections. The high-current
input loop goes from the positive terminal of the input
capacitor to the inductor, to the internal MOSFET,
then to the input capacitor’s negative terminal. The
high-current output loop is from the positive termi-
nal of the input capacitor to the inductor, to the rec-
tifier diode, to the positive terminal of the output
capacitors, reconnecting between the output
capacitor and input capacitor ground terminals.
Avoid using vias in the high-current paths. If vias
are unavoidable, use multiple vias in parallel to
reduce resistance and inductance.
3) Create a ground island (PGND) consisting of the
input and output capacitor ground and negative ter-
minal of the current-sense resistor. Connect all
these together with short, wide traces or a small
ground plane. Maximizing the width of the power-
ground traces improves efficiency and reduces out-
put-voltage ripple and noise spikes. Create an
analog ground island (AGND) consisting of the
overvoltage detection divider ground connection,
the ISET and FSET resistor connections, CCV
capacitor connections, and the device’s exposed
backside pad. Connect the AGND and PGND
islands by connecting the GND pins directly to the
exposed backside pad. Make no other connections
between these separate ground planes.
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| MAX17061EVCMAXQU+ | 功能描述:LED 照明开发工具 Evaluation Kit/Evaluation System for the MAX17061 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: |
| MAX17061EVKIT+ | 功能描述:LED 照明开发工具 MAX17061 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: |
| MAX17062ETB+ | 制造商:Maxim Integrated Products 功能描述: 制造商:Maxim Integrated Products 功能描述:TFT-LCD STEP-UP DC-DC CONVERTER - Rail/Tube |
| MAX17062ETB+T | 功能描述:直流/直流开关转换器 TFT-LCD Step-Up DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX17062EVKIT | 功能描述:电源管理IC开发工具 MAX17062 Eval Kit RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
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