參數(shù)資料
型號: LM5025AMTC
廠商: NATIONAL SEMICONDUCTOR CORP
元件分類: 穩(wěn)壓器
英文描述: Active Clamp Voltage Mode PWM Controller
中文描述: 3 A SWITCHING CONTROLLER, 650 kHz SWITCHING FREQ-MAX, PDSO16
封裝: TSSOP-16
文件頁數(shù): 13/16頁
文件大?。?/td> 698K
代理商: LM5025AMTC
Feed-Forward Ramp
(Continued)
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 20μA current is
sourced out of the softstart pin (SS) into an external capaci-
tor. 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
undervoltage, line
undervoltage (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 1μAuntil the first output pulse is generated by the
PWM comparator. The current source returns to the nominal
20μA 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 tem-
perature is exceeded. When activated, typically at 165C,
the controller is forced into a low power standby state with
the output drivers and the bias regulator disabled. The de-
vice will restart after the thermal hysteresis (typically 25C).
During a restart after thermal shutdown, the softstart capaci-
tor will be fully discharged and then charged in the low
current mode (1μA) similar to a second level current limit
event. The thermal protection feature is provided to prevent
catastrophic failures from accidental device overheating.
L
www.national.com
13
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LM5025AMTC/NOPB 功能描述:電壓模式 PWM 控制器 100V Forward Active Clamp RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓撲結(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel
LM5025AMTCX 制造商:Texas Instruments 功能描述:Voltage Mode PWM Controller 3A/1A 16-Pin TSSOP T/R
LM5025AMTCX/MEY8 制造商:Texas Instruments 功能描述:
LM5025AMTCX/NOPB 功能描述:電壓模式 PWM 控制器 RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓撲結(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel
LM5025ASD 功能描述:電壓模式 PWM 控制器 RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓撲結(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel