- 您现在的位置：买卖IC网 > PDF目录80199 > LM27402SQ (NATIONAL SEMICONDUCTOR CORP) SWITCHING CONTROLLER, 1350 kHz SWITCHING FREQ-MAX, QCC16 PDF资料下载
参数资料
| 型号： | LM27402SQ |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING CONTROLLER, 1350 kHz SWITCHING FREQ-MAX, QCC16 |
| 封装： | 4 X 4 MM, 0.80 MM HEIGHT, 0.65 MM PITCH, LLP-16 |
| 文件页数： | 10/32页 |
| 文件大小： | 653K |
| 代理商： | LM27402SQ |
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页当前第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页第28页第29页第30页第31页第32页
30092623
FIGURE 13. Control Loop Schematic Diagram
The powertrain consists of the filter inductor (L) with DCR
(R
DCR), output capacitor (COUT) with ESR (effective series re-
sistance R
ESR), and effective load resistance (RO). The error
amplifier (EA) regulates the feedback pin (FB) to 0.6V. The
passive compensation components around the error amplifier
help maintain system stability. Type III compensation is
shown in Figure 13. The PWM modulator establishes the duty
cycle command by comparing the error amplifier output
(COMP) with an internally generated ramp set at the switching
frequency.
The modulator gain, powertrain and compensator transfer
functions must be taken into consideration when obtaining the
total open loop transfer function. The PWM modulator adds a
DC gain to the open loop transfer function. In a basic voltage
mode system, the PWM gain will vary with input voltage.
However the LM27402 internal voltage feed-forward circuitry
maintains a constant PWM gain of 7:
The powertrain transfer function includes the output inductor
with DCR, output capacitor with ESR, and load resistance.
The inductor and capacitor create two complex poles at a fre-
quency described by:
A left half plane zero is created by the output capacitor ESR
located at a frequency described by:
The complete powertrain transfer function is:
The bode plot of the above transfer function can be seen in
30092698
FIGURE 14. Powertrain Bode Plot
The complex poles (f
LC) created by the filter inductor and out-
put capacitor cause a 180° phase shift as seen in Figure 14.
The phase is boosted back up to -90° by virtue of the output
capacitor ESR zero. The phase shift caused by the complex
poles must be compensated to stabilize the loop response.
The compensation network shown around the error amplifier
in Figure 13 creates two poles, two zeros and a pole at the
origin. Placing these poles and zeros at the correct frequen-
cies will optimize the loop response. The compensator trans-
fer function is:
The pole located at the origin provides high DC gain to opti-
mize DC load regulation performance. The other two poles
and two zeros can be located accordingly to stabilize the volt-
age mode loop depending on the power stage complex poles
and damping characteristic Q. Figure 15 is an illustration of
what the error amplifier compensation transfer function will
look like.
www.national.com
18
LM27402
相关PDF资料 |
PDF描述 |
|---|---|
| LM4040C25H5TA | 1-OUTPUT TWO TERM VOLTAGE REFERENCE, 2.5 V, PDSO5 |
| LT1460DCS8-51460 | 1-OUTPUT THREE TERM VOLTAGE REFERENCE, 5 V, PDSO8 |
| LM4040CIZ-3.0/NOPB | 1-OUTPUT TWO TERM VOLTAGE REFERENCE, 3 V, PBCY3 |
| LTC2911CTS8-4#TRMPBF | POWER SUPPLY SUPPORT CKT, PDSO8 |
| LED15-24S15W-A | 1-OUTPUT 15 W DC-DC REG PWR SUPPLY MODULE |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LM27402SQ/NOPB | 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 |
| LM27402SQEVAL/NOPB | 功能描述:电源管理IC开发工具 LM27402SQ EVAL BOARD 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 |
| LM27402SQX | 制造商:NSC 制造商全称:National Semiconductor 功能描述:High Performance Synchronous Buck Controller with DCR Current Sensing |
| LM27402SQX/NOPB | 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 |
| LM27403 | 制造商:TI 制造商全称:Texas Instruments 功能描述:Synchronous Buck Controller with Temperature-Compensated, Inductor-DCR-Based Overcurrent Protection and Programmable Thermal Shutdown |
发布紧急采购，3分钟左右您将得到回复。