- 您现在的位置：买卖IC网 > Datasheet目录340 > MAX17061ETI+T (Maxim Integrated)IC LED DRVR WHITE BCKLGT 28-TQFN Datasheet资料下载
参数资料
| 型号： | MAX17061ETI+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 21/26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
The equations used here include a constant LIR, which
is the ratio of the inductor peak-to-peak ripple current
to the average DC inductor current at the full load cur-
,
I IN ( DCMAX ) =
I OUT(MAX ) × V OUT
V IN ( MIN ) × η MIN
rent. The controller operates in DCM mode when LIR is
higher than 2.0, and it works in CCM mode when LIR is
lower than 2.0. The best trade-off between inductor size
2) Calculate the ripple current at that operating point
and the peak current required for the inductor:
and converter efficiency for step-up regulators generally
has an LIR between 0.3 and 0.5. However, depending
on the AC characteristics of the inductor core material
and ratio of inductor resistance to other power-path
I RIPPLE =
V IN ( MIN ) × ( V OUT ( MAX ) ? V IN ( MIN )
L × V OUT ( MAX ) × f OSC
)
resistances, the best LIR can shift up or down. If the
inductor resistance is relatively high, more ripples can
be accepted to reduce the number of required turns and
increase the wire diameter. If the inductor resistance is
relatively low, increasing inductance to lower the peak
current can reduce losses throughout the power path. If
extremely thin high-resistance inductors are used, as is
common for LCD panel applications, LIR higher than 2.0
Inductor Selection in DCM Operation
When DCM operating mode is chosen to minimize the
inductor value, the calculations are different from those
above in CCM mode. The maximum inductor value for
DCM mode is calculated with the following equation:
The peak-inductor current in DCM is calculated with fol-
lowing equation:
L DCM ( MAX ) = ? 1 ?
V OUT ( MAX ) + V DIODE ?
can be chosen for DCM operating mode.
Once a physical inductor is chosen, higher and lower val-
ues of the inductor should be evaluated for efficiency
?
?
V IN ( MIN ) ?
?
improvements in typical operating regions. The detail
design procedure for CCM can be described as follows:
Inductor Selection in CCM Operation
×
V IN ( MIN ) 2 × η
2 × f OSC ( MAX ) × V OUT ( MAX ) × I OUT ( MAX )
I PEAK IN ( DCMAX ) + RIPPLE
= I
2
? V IN _ MIN ? ? V OUT ? V IN _ MIN ? ? η TYP ?
L = ? ? ? ? ? ?
( V OUT ( MAX ) + V DIODE IN ( MIN ) ) × R S
2 × 24 . 7 mV × f OSC ( MIN )
35 . 9 V ? 7 V ? ? 0 . 85 ?
? 7 V ? ?
L = ? ? ? ? ? ? = 9 . 44 μ H
( ) × 12 m Ω = 6 . 0 μ H
L CCM ( MIN ) =
1) Calculate the approximate inductor value using the
typical input voltage (V IN ), the maximum output cur-
rent (I OUT(MAX) ), the expected efficiency ( η TYP )
taken from an appropriate curve in the Typical
Operating Characteristics, and an estimate of LIR
based on the above discussion:
2
? V OUT ? ? I OUT ( MAX ) × f OSC ? ? LIR ?
The MAX17061 has a minimum inductor value limitation
for a stable operation in CCM mode at low input voltage
because of the internal fixed-slope compensation. The
minimum inductor value for stability is calculated with
the following equation:
? 2 × V
L CCM ( MIN ) =
where 24.7mV is a scale factor from slope compensa-
tion, and the R S is the equivalent current-sensing scale
factor (12m Ω typ):
1) Choose an available inductor value from an appropri-
ate inductor family. Calculate the maximum DC input
current at the minimum input voltage V IN(MIN), using
conservation of energy and the expected efficiency
at that operating point ( η MIN ) taken from an appropri-
ate curve in the Typical Operating Characteristics:
I
,
The inductor’s saturation current rating should exceed
I PEAK and the inductor ’s DC current rating should
exceed I IN(DC,MAX) . For good efficiency, choose an
inductor with less than 0.1 Ω series resistance.
Inductor Selection Design
Examples:
Considering the Typical Operating Circuit with four
10-LED strings and 25mA LED full-scale current, the
maximum load current (I OUT(MAX) ) is 100mA with a
35.9V output and a minimal input voltage of 7V.
Choosing a CCM operating mode with LIR = 1 at 1MHz
and estimating efficiency of 85% at this operating point:
2
? 35 . 9 V ? ? 100 mA × 1 MHz ? ? 1 ?
In CCM, the inductor has to be higher than L CCM(MIN):
35 . 9 V + 0 . 4 V ? 2 × 7 V
2 × 24 . 7 mV × 0 . 9 MHz
A10μH inductor is chosen, which is higher than the
minimum L that guarantees stability in CCM.
______________________________________________________________________________________
21
相关PDF资料 |
PDF描述 |
|---|---|
| MAX17105ETG+T | IC LED DRVR WHITE BCKLGT 24-TQFN |
| MAX17127ETP+ | IC WLED DVR SIX STRING 20TQFN |
| MAX17149ETE+ | IC LED DRVR 6CH STEP UP 16QFNEP |
| MAX17410EVKIT+ | KIT EVAL FOR MAX17410 CTLR |
| MAX17605AUA+ | IC MOSFET DRVR 4A DUAL 8UMAX |
相关代理商/技术参数 |
参数描述 |
|---|---|
| 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 |
发布紧急采购，3分钟左右您将得到回复。