- 您现在的位置：买卖IC网 > PDF目录1839 > MAX17112ETB+T (Maxim Integrated Products)IC CONV DC-DC STEP UP 10TDFN PDF资料下载
参数资料
| 型号： | MAX17112ETB+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 8/12页 |
| 文件大小： | 0K |
| 描述： | IC CONV DC-DC STEP UP 10TDFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 1 |
| 应用： | LCD 监视器，笔记本电脑显示器 |
| 电源电压： | 2.6 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 10-WFDFN 裸露焊盘 |
| 供应商设备封装： | 10-TDFN-EP（3x3） |
| 包装： | 标准包装 |
| 产品目录页面： | 1412 (CN2011-ZH PDF) |
| 其它名称： | MAX17112ETB+TDKR |
High-Performance, Step-Up, DC-DC Converter
I OUT ( MAX ) = ? I LIM -
×η
?×
Output Current Capability
The output current capability of the MAX17112 is a
function of current limit, input voltage, operating fre-
quency, and inductor value. Because of the slope com-
pensation used to stabilize the feedback loop, the
inductor current limit depends on the duty cycle. The
current limit is determined by the following equation:
I LIM = (1.26 - 0.35 × D) × I LIM_EC
where I LIM_EC is the current limit specified at 75% duty
cycle (see the Electrical Characteristics table) and D is
the duty cycle.
The output current capability depends on the current-
limit value and is governed by the following equation:
? 0.5 × D × V IN ? V IN
? f OSC × L ? V OU T
where I LIM is the current limit calculated above, η is the
regulator efficiency (85% nominal), D is the duty cycle,
and f OSC is switching frequency. The duty cycle when
operating at the current limit is:
V L Undervoltage Lockout (UVLO)
The undervoltage lockout (UVLO) circuit compares the
voltage at V L with the UVLO (2.45V typ) to ensure that
the input voltage is high enough for reliable operation.
The 50mV (typ) hysteresis prevents supply transients
from causing a restart. Once the V L voltage exceeds the
UVLO-rising threshold, the startup begins. When the
input voltage falls below the UVLO-falling threshold, the
main step-up regulator turns off.
Startup Using SHDN
The MAX17112 can be enabled by applying high volt-
age on the SHDN pin. Figure 2 shows the block dia-
gram of the internal SHDN pin function. There are two
ways to apply this high voltage. When SHDN is con-
nected to an external capacitor, an internal 5μA current
source charges up this capacitor and when the voltage
on SHDN passes 1.24V, the IC starts up. Another way
to enable the IC through the SHDN pin is to directly
apply a logic-high signal to SHDN instead of connect-
ing a capacitor.
The delay time for startup by connecting an external
capacitor at SHDN can be estimated using the follow-
ing equation:
D =
V OUT - V IN + V DIODE
V OUT - I LIM × R ON + V DIODE
t Delay =
1.24 V
5 μA
× C SHDN ≈ 0 . 25 × C SHDN
where V DIODE is the rectifier diode forward voltage and
R ON is the on-resistance of the internal MOSFET.
Soft-Start
The MAX17112 can be programmed for soft-start upon
power-up with an external capacitor. When the shut-
down pin is taken high, the soft-start capacitor (C SS ) is
immediately charged to 0.4V. Then the capacitor is
charged at a constant current of 4μA (typ). During this
time, the SS voltage directly controls the peak inductor
current period. Full current limit is readied at V SS = 1.5V.
The maximum load current is available after the soft-
start is completed. When SHDN is low, SS is discharged
to ground.
Overvoltage Protection (OVP)
To prevent damage due to an input surge voltage, the
MAX17112 integrates an OVP circuit. There is an internal
switch between IN and V L , which is on when the IN volt-
age is less than 6.6V (typ). The switch is off when the IN
exceeds 6.6V (typ). Since V L supplies the IC, the switch
protects the IC from damage when excessively high
voltage is applied to IN.
where C SHDN is in microfarads.
When enabling the IC by applying a logic-high signal to
SHDN , a series resistor should be inserted between the
logic signal and SHDN for protection purposes. This
resistor can help limit the current drawn from the logic
signal supply into the SHDN pin when SHDN is dis-
charged to GND through the internal switch at the
moment of startup when V L < UVLO. A typical value for
this resistor is 10k Ω . Figure 3 shows the application cir-
cuit for this enabling method of applying a logic-high
signal to SHDN through a 10k Ω resistor.
8
_______________________________________________________________________________________
相关PDF资料 |
PDF描述 |
|---|---|
| MAX17117ETJ+ | IC REG INTERNAL SW BOOST 32TQFN |
| MAX17120ETJ+ | IC DRVR SCAN TFT LDC 32-TQFN |
| MAX1714AEEP+T | IC REG CTRLR BUCK PWM CM 20-QSOP |
| MAX1715EEI | IC REG CTRLR BUCK PWM 28-QSOP |
| MAX1716EEG+ | IC REG CTRLR BUCK PWM CM 24-QSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX17112EVKIT+ | 功能描述:电源管理IC开发工具 MAX17112 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 |
| MAX17113ETL+ | 功能描述:其他电源管理 Power-Supply Controller RoHS:否 制造商:Texas Instruments 输出电压范围: 输出电流:4 mA 输入电压范围:3 V to 3.6 V 输入电流: 功率耗散: 工作温度范围:- 40 C to + 110 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-48 封装:Reel |
| MAX17113ETL+T | 功能描述:LCD 驱动器 Power-Supply Controller RoHS:否 制造商:Maxim Integrated 数位数量:4.5 片段数量:30 最大时钟频率:19 KHz 工作电源电压:3 V to 3.6 V 最大工作温度:+ 85 C 最小工作温度:- 20 C 封装 / 箱体:PDIP-40 封装:Tube |
| MAX17113EVKIT+ | 功能描述:电源管理IC开发工具 MAX17113 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 |
| MAX17114ETM | 制造商:MAXIM 功能描述:Pb Free |
发布紧急采购，3分钟左右您将得到回复。