參數(shù)資料
型號(hào)： L6730
廠商： 意法半導(dǎo)體
英文描述： Adjustable step-down controller with synchronous rectification
中文描述： 可調(diào)式降壓同步整流控制器
文件頁(yè)數(shù)： 30/52頁(yè)
文件大?。?/td> 1370K
代理商： L6730
Device description
L6730 - L6730B
30/52
5.14 Bootstrap anti-discharging system
This built-in anti-discharging system keeps the voltage going across the bootstrap capacitor
from going below 3.3V. An internal comparator senses the voltage across the external
bootstrap capacitor and helps to keep it charged, eventually turning on the low-side MOSFET
for approximately 200ns. If the bootstrap capacitor is not charged up enough, the high-side
MOSFET cannot be effectively turned on and it will present a higher R
DS(on)
. In some cases,
the OCP can be also triggered. There are up to two conditions during which the bootstrap
capacitor can be discharged:
fan power supply failure, and
no sink at zero current operation.
●
●
5.14.1 Fan power supply failure
In many applications the fan is driven by a DC motor that uses a DC/DC converter. Often only
the speed of the motor is controlled by varying the voltage applied to the input terminal and
there is no control on the torque because the current is not directly controlled. The current has
to be limited in case of overload or short-circuit, but without stopping the motor.
With the L6730B, the current can be limited without shutting down the system because
constant current protection is provided. In order to vary the motor speed, the output voltage of
the converter must be varied. Both L6730 and L6730B have a dedicated EAREF pin (see
Table
3.
) which provides an external reference to the non-inverting input of the error-amplifier.
In these applications the duty cycle depends on the motor’s speed and sometimes a 100% duty
cycle setting has to be used to attain the maximum speed. In these conditions, the bootstrap
capacitor can not be recharged and the system cannot work properly. Some PWM controllers
limit the maximum duty cycle to 80 or 90% in order to keep the bootstrap capacitor charged, but
this makes performance during the load transient worse. The “bootstrap anti-discharging
system” allows the L6730x to work at 100% without any problem.
Figure 25.: 100% Duty Cycle Operation on page 31
shows The following picture illustrates the
device behavior when the input voltage is 5V and a 100% duty cycle is set by an external
reference.
相關(guān)PDF資料
PDF描述
L6730B Adjustable step-down controller with synchronous rectification
L6730BTR Adjustable step-down controller with synchronous rectification
L6730TR Adjustable step-down controller with synchronous rectification
L6740L Hybrid controller (4+1) for AMD SVID and PVID processors
L6740LTR Hybrid controller (4+1) for AMD SVID and PVID processors
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
L6730_09 制造商:STMICROELECTRONICS 制造商全稱(chēng):STMicroelectronics 功能描述:Adjustable step-down controller with synchronous rectification
L6730B 功能描述:DC/DC 開(kāi)關(guān)控制器 Adjustable Step Down Controller RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開(kāi)關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK
L6730BTR 功能描述:DC/DC 開(kāi)關(guān)控制器 Adjustable Step Down Controller RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開(kāi)關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK
L6730C 功能描述:IC REG CTRLR BUCK PWM VM 20TSSOP RoHS:是 類(lèi)別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:100% 電源電壓:8.2 V ~ 30 V 降壓:無(wú) 升壓:無(wú) 回掃:是 反相:無(wú) 倍增器:無(wú) 除法器:無(wú) Cuk:無(wú) 隔離:是 工作溫度:0°C ~ 70°C 封裝/外殼:8-DIP（0.300"，7.62mm） 包裝:管件 產(chǎn)品目錄頁(yè)面:1316 (CN2011-ZH PDF)
L6730CQ 制造商:STMICROELECTRONICS 制造商全稱(chēng):STMicroelectronics 功能描述:Adjustable step-down controller with synchronous rectification
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