參數(shù)資料
型號: L6730D
廠商: STMICROELECTRONICS
元件分類: 穩(wěn)壓器
英文描述: 20 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO20
封裝: HTSSOP-20
文件頁數(shù): 21/50頁
文件大?。?/td> 1486K
代理商: L6730D
Device description
L6730C - L6730D
28/50
5.14
Bootstrap anti-discharging system
This built-in system avoids that the voltage across the bootstrap capacitor becomes less than
3.3V. An internal comparator senses the voltage across the external bootstrap capacitor
keeping it charged, eventually turning-on the low-side MOSFET for approximately 200ns. If the
bootstrap capacitor is not enough charged the high-side MOSFET cannot be effectively turned-
on and it will present a higher RDS(on). In some cases the OCP can be also triggered. It’s
possible to mention at least two application conditions during which the bootstrap capacitor can
be discharged:
5.14.1 Fan’s power supply
In many applications the FAN is a DC MOTOR driven by a voltage-mode DC/DC converter.
Often only the speed of the MOTOR is controlled by varying the voltage applied to the input
terminal and there’s no control on the torque because the current is not directly controlled.
Obviously the current has to be limited in case of overload or short-circuit but without stopping
the MOTOR. With the L6730D the current can be limited without shutting down the system
because a constant-current-protection is provided. In order to vary the MOTOR speed the
output voltage of the converter must be varied. Both L6730C and L6730D have a dedicated pin
called EAREF (see the related section) that allows providing 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 100% has
to be set in order to go at the maximum speed. Unfortunately in these conditions the bootstrap
capacitor can not be recharged and the system cannot work properly. Some PWM controller
limits the maximum duty-cycle to 80-90% in order to keep the bootstrap cap charged but this
make worse the performance during the load transient. Thanks to the “bootstrap anti-
discharging system” the L6730X can work at 100% without any problem. The following picture
shows the device behaviour when input voltage is 5V and 100% is set by the external
reference.
Figure 23. 100% duty cycle operation
Vout=5V
Vin=5V
LGate
Fsw?6.3KHz
TOFF
≈ 200ns
Vout=5V
Vin=5V
LGate
Fsw?6.3KHz
TOFF
≈ 200ns
VOUT = 5V
VIN = 5V
LGate
FSW
≈ 6.3KHz
相關(guān)PDF資料
PDF描述
L6730CQTR 20 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, QCC24
L6730CTR 20 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO20
L6730 20 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO20
L6730B 20 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO20
L6730TR 20 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO20
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
L6730DTR 功能描述:IC REG CTRLR BUCK PWM VM 20TSSOP RoHS:是 類別: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 升壓:無 回掃:是 反相:無 倍增器:無 除法器:無 Cuk:無 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)品目錄頁面:1316 (CN2011-ZH PDF)
L6730TR 功能描述:DC/DC 開關(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
L6731B 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 Adj. Step-Down w/ Synch Rectification RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
L6731BTR 功能描述:IC CTRLR ADJ STEP DOWN 16-TSSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,000 系列:- 應(yīng)用:電源,ICERA E400,E450 輸入電壓:4.1 V ~ 5.5 V 輸出數(shù):10 輸出電壓:可編程 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:42-WFBGA,WLCSP 供應(yīng)商設(shè)備封裝:42-WLP 包裝:帶卷 (TR)
L6731D 功能描述:DC/DC 開關(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