參數(shù)資料
型號(hào): L6728
廠商: 意法半導(dǎo)體
英文描述: Single phase PWM controller with PowerGOOD
中文描述: 單相PWM控制器與電源良好
文件頁數(shù): 11/32頁
文件大?。?/td> 942K
代理商: L6728
L6728
Soft start
11/32
7
Soft start
L6728 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 0V to 0.8V in 4.5ms (typ.), in closed loop regulation, linearly charging
the output capacitors to the final regulation voltage.
In the event of an over current triggering during soft start, the over current logic will override
the soft start sequence and will shut down the PWM logic and both the high side and low
side gates. This condition is latched, cycle VCC to recover.
The device begins soft start phase only when VCC power supply is above UVLO threshold
and over current threshold setting phase has been completed.
7.1
Low-Side-Less Start up (LSLess)
In order to avoid any kind of negative undershoot and dangerous return from the load during
start-up, L6728 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)
相關(guān)PDF資料
PDF描述
L6728TR Single phase PWM controller with PowerGOOD
L6731B Transistor; Type: Amplifiers/Bipolar; VCEO (V): 25; Ic (A): 1; Pc (W): 0.8; hFE: 85 to 330; VCE (sat) (V) max: 0.5; Package: TO-92Mod
L6731BTR Transistor; Type: Amplifiers/Bipolar; VCEO (V): -25; Ic (A): -1; Pc (W): 0.8; hFE: 85 to 330; VCE (sat) (V) max: -0.5; Package: TO-92Mod
L6732 Adjustable step-down controller with synchronous rectification
L6732TR Adjustable step-down controller with synchronous rectification
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
L6728_0706 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Single phase PWM controller with Power Good
L6728A 功能描述:電壓模式 PWM 控制器 Hi-Freq. singl-phase PWM controller w/Po 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
L6728AH 功能描述:軟開關(guān) PWM 控制器 Sgl Output 600 KHz DFPN-10 RoHS:否 制造商:Fairchild Semiconductor 輸出端數(shù)量: 輸出電流: 開關(guān)頻率: 工作電源電壓:30 V 電源電流: 最大工作溫度:+ 105 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel
L6728AHTR 功能描述:電流型 PWM 控制器 HIGH FREQ PWM CNTRL W/PO RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)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
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