- 您现在的位置：买卖IC网 > PDF目录1839 > MAX17100ETM+T (Maxim Integrated Products)IC REG BOOST INT-SWITCH 48-TQFN PDF资料下载
参数资料
| 型号： | MAX17100ETM+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 28/35页 |
| 文件大小： | 0K |
| 描述： | IC REG BOOST INT-SWITCH 48-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 应用： | LCD 电视机/监控器 |
| 电源电压： | 2.5 V ~ 6 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 48-WFQFN 裸露焊盘 |
| 供应商设备封装： | 48-TQFN-EP（6x6） |
| 包装： | 带卷 (TR) |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页当前第28页第29页第30页第31页第32页第33页第34页第35页
Internal-Switch Boost Regulator with Integrated Scan
Driver, VCOM Calibrator, and Op Amp for TFT LCDs
Pass-Transistor Selection
The pass transistor must meet specifications for current
gain (h FE(MIN) ), input capacitance, collector-emitter
saturation voltage, and power dissipation. The transis-
tor’s current gain limits the guaranteed maximum output
current to:
where V T is 26mV at room temperature and I BIAS is the
current through the base-to-emitter resistor (R BE ). For
the MAX17100, the bias currents for both the gate-on
and gate-off linear-regulator controllers are 0.1mA.
Therefore, the base-to-emitter resistor for both linear
regulators should be chosen to set 0.1mA bias current:
I LOAD(MAX) DRV - BE ) × h FE(MIN)
V BE 0.7V
=(I
V
R BE
R BE =
=
0.1mA 0.1mA
= 6.8k ?
where I DRV is the minimum guaranteed base-drive cur-
rent, V BE is the transistor’s base-to-emitter forward volt-
age drop, and R BE is the pullup resistor connected
between the transistor’s base and emitter. Furthermore,
the transistor’s current gain increases the linear regula-
tor’s DC loop gain (see the Stability Requirements sec-
tion), so excessive gain destabilizes the output.
Therefore, transistors with current gain over 100 at the
maximum output current can be difficult to stabilize and
are not recommended unless the high gain is needed
to meet the load-current requirements.
The output capacitor and the load resistance create the
dominant pole in the system. However, the internal
amplifier delay, pass transistor’s input capacitance,
and the stray capacitance at the feedback node create
additional poles in the system, and the output capaci-
tor’s ESR generates a zero. For proper operation, use
the following equations to verify the linear regulator is
properly compensated:
1) First, determine the dominant pole set by the linear
regulator’s output capacitor and the load resistor:
The transistor’s saturation voltage at the maximum out-
put current determines the minimum input-to-output
voltage differential that the linear regulator can support.
f POLE_LR =
I LOAD(MAX)_LR
2 × C OUT_LR × V OUT_LR
Also, the package’s power dissipation limits the usable
maximum input-to-output voltage differential. The maxi-
mum power-dissipation capability of the transistor’s
package and mounting must exceed the actual power
dissipated in the device. The power dissipated equals
the maximum load current (I LOAD(MAX)_LR ) multiplied
by the maximum input-to-output voltage differential:
P = I LOAD(MAX)_LR × (V IN(MAX)_LR - V OUT_LR )
The unity-gain crossover of the linear regulator is:
f CROSSOVER = A V_LR x f POLE_LR
2) The pole created by the internal amplifier delay is
approximately 1MHz:
f POLE_AMP = 1MHz
3) Next, calculate the pole set by the transistor’s input
capacitance, the transistor’s input resistance, and
the base-to-emitter pullup resistor:
where V IN(MAX)_LR is the maximum input voltage of the
linear regulator and V OUT_LR is the output voltage of
the linear regulator.
f POLE_IN =
1
2 × C I N × (R BE //R IN )
C IN = m , R IN = FE
Stability Requirements
The MAX17100 linear-regulator controllers use an inter-
nal transconductance amplifier to drive an external
pass transistor. The transconductance amplifier, the
pass transistor, the base-emitter resistor, and the out-
put capacitor determine the loop stability. The following
applies to both linear-regulator controllers in the
MAX17100.
where:
g h
2 f T g m
g m is the transconductance of the pass transistor and f T
is the transition frequency. Both parameters can be found
in the transistor’s data sheet. Because R BE is much
greater than R IN , the above equation can be simplified:
The transconductance amplifier regulates the output
voltage by controlling the pass transistor’s base cur-
rent. The total DC loop gain is approximately:
f POLE_IN =
1
2 π × C IN × R IN
) × [1 + ( BIAS
A V_LR ? (
10
V T
I × h EF
I LOAD_LR
)] × V REF
28
______________________________________________________________________________________
相关PDF资料 |
PDF描述 |
|---|---|
| MAX17101ETJ+T | IC REG CTRLR DIV PWM CM 32TQFNEP |
| MAX17108ETI+T | IC LEVEL SHIFTER 10CH 28TQFN |
| MAX17112ETB+T | IC CONV DC-DC STEP UP 10TDFN |
| MAX17117ETJ+ | IC REG INTERNAL SW BOOST 32TQFN |
| MAX17120ETJ+ | IC DRVR SCAN TFT LDC 32-TQFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX17100EVKIT+ | 功能描述:电源管理IC开发工具 MAX17100 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 |
| MAX17101+SMP | 功能描述:DC/DC 开关控制器 RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX17101ETJ+ | 功能描述:DC/DC 开关控制器 Dual PWM Step-Down Controller RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX17101ETJ+T | 功能描述:DC/DC 开关控制器 Dual PWM Step-Down Controller RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX17101ETJ+TS | 功能描述:DC/DC 开关控制器 RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
发布紧急采购，3分钟左右您将得到回复。