參數(shù)資料
型號: L6728AHTR
廠商: STMICROELECTRONICS
元件分類: 穩(wěn)壓器
英文描述: SWITCHING CONTROLLER, PDSO10
封裝: 3 X 3 MM, ROHS COMPLIANT, VFDFPN-10
文件頁數(shù): 3/33頁
文件大小: 1033K
代理商: L6728AHTR
L6728AH
Soft-start
Doc ID 15726 Rev 1
11/33
6
Soft-start
L6728AH implements a soft-start to smoothly charge the output filter avoiding high in-rush
currents to be required from the input power supply. The device gradually increases the
internal reference from 0 V to 0.8 V in 4.5 msec (typ.), in closed loop regulation, linearly
charging the output capacitors to the final regulation voltage. A pre-charged output voltage
will affect the soft-start duration, resulting in a reduction of this period of time (< 4 msec).
During the soft-start process all the protections but the UVP are active: the UVP becomes
active as soon as the soft-start ends up.
The device begins soft-start phase only when VCC power supply is above UVLO threshold
and over-current threshold setting phase has been completed.
6.1
Low-side-less start up (LSLess)
In order to avoid any kind of negative undershoot and dangerous return from the load during
start-up, L6728AH performs a special sequence in enabling LS driver to switch: during the
soft-start phase, the LS driver results disabled (LS = OFF) until the HS starts to switch. This
avoid the dangerous negative spike on the output voltage that can happen if starting over a
pre-biased output.
If the output voltage is pre-biased to a voltage higher than the final one, the HS would never
start to switch. In this case, at the end of soft-start time, LS is enabled and discharge the
output to the final regulation value.
This particular feature of the device masks the LS turn-on only from the control loop point of
view: protections by-pass this turning ON the LS MOSFET in case of need.
Figure 4.
LSLess startup (left) vs. non-LSLess startup (right)
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
L6728ATR 功能描述:電壓模式 PWM 控制器 HIGH FREQ SINGLE PHASE PWM CNTRL RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(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
L6728D 功能描述:電流型 PWM 控制器 SNGL PHASE PWM CONTROLLER RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14
L6728DTR 功能描述:電流型 PWM 控制器 Single-Phase PWM 5V to 12V Controller RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14
L6728H 功能描述:電壓模式 PWM 控制器 Sgl Output 300 KHz DFN-10 RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(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
L6728HTR 功能描述:電流型 PWM 控制器 SINGLE PHASE PWM CNTRL PWR GOOD RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14