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参数资料
| 型号： | LM5025CCMTE |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING CONTROLLER, 650 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封装： | TSSOP-16 |
| 文件页数： | 4/16页 |
| 文件大小： | 369K |
| 代理商： | LM5025CCMTE |
Feed-Forward Ramp
An external resistor (R
FF) and capacitor (CFF) connected to
V
IN and GND are required to create the PWM ramp signal.
The slope of the signal at the RAMP pin will vary in proportion
to the input line voltage. This varying slope provides line feed-
forward information necessary to improve line transient re-
sponse with voltage mode control. The RAMP signal is
compared to the error signal at the COMP pin by the pulse
width modulator comparator to control the duty cycle of the
main switch output. The Volt Second Clamp comparator also
monitors the RAMP pin and if the ramp amplitude exceeds
2.5V the present cycle is terminated. The ramp signal is reset
to GND at the end of each cycle by either the internal clock
or the Volt Second comparator, which ever occurs first.
Soft-Start
The softstart feature allows the power converter to gradually
reach the initial steady state operating point, thus reducing
start-up stresses and surges. At power on, a 90 A current is
sourced out of the softstart pin (SS) into an external capacitor.
The capacitor voltage will ramp up slowly and will limit the
COMP pin voltage and therefore the PWM duty cycle. In the
event of a fault as determined by V
CC undervoltage, line un-
dervoltage (UVLO) or second level current limit, the output
gate drivers are disabled and the softstart capacitor is fully
discharged. When the fault condition is no longer present a
softstart sequence will be initiated. Following a second level
current limit detection (CS2), the softstart current source is
reduced to 1 A until the first output pulse is generated by the
PWM comparator. The current source returns to the nominal
90 A level after the first output pulse (~1V at the SS pin).
Thermal Protection
Internal Thermal Shutdown circuitry is provided to protect the
integrated circuit in the event the maximum junction temper-
ature is exceeded. When activated, typically at 165°C, the
controller is forced into a low power standby state with the
output drivers and the bias regulator disabled. The device will
restart after the thermal hysteresis (typically 25°C). During a
restart after thermal shutdown, the softstart capacitor will be
fully discharged and then charged in the low current mode (1
A) similar to a second level current limit event. The thermal
protection feature is provided to prevent catastrophic failures
from accidental device overheating.
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LM5025C
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LM5025CMTC | 制造商:NSC 制造商全称:National Semiconductor 功能描述:Active Clamp Voltage Mode PWM Controller |
| LM5025CMTC/NOPB | 功能描述:电压模式 PWM 控制器 RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| LM5025CMTCE/NOPB | 功能描述:电压模式 PWM 控制器 RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| LM5025CMTCX | 制造商:Texas Instruments 功能描述:Voltage Mode PWM Controller 3A 16-Pin TSSOP T/R |
| LM5025CMTCX/NOPB | 功能描述:电压模式 PWM 控制器 RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
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