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参数资料
| 型号： | L6730CQTR |
| 厂商： | STMICROELECTRONICS |
| 元件分类： | 稳压器 |
| 英文描述： | 20 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, QCC24 |
| 封装： | 4 X 4 MM, QFN-24 |
| 文件页数： | 21/50页 |
| 文件大小： | 1486K |
| 代理商： | L6730CQTR |
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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
相关PDF资料 |
PDF描述 |
|---|---|
| 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 |
| L6732CTR | 20 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO16 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| L6730CTR | 功能描述:IC REG CTRLR BUCK PWM VM 20TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:100% 电源电压:8.2 V ~ 30 V 降压:无 升压:无 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:0°C ~ 70°C 封装/外壳:8-DIP（0.300"，7.62mm） 包装:管件 产品目录页面:1316 (CN2011-ZH PDF) |
| L6730D | 功能描述:IC REG CTRLR BUCK PWM VM 20TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:100% 电源电压:8.2 V ~ 30 V 降压:无 升压:无 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:0°C ~ 70°C 封装/外壳:8-DIP（0.300"，7.62mm） 包装:管件 产品目录页面:1316 (CN2011-ZH PDF) |
| L6730DTR | 功能描述:IC REG CTRLR BUCK PWM VM 20TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:100% 电源电压:8.2 V ~ 30 V 降压:无 升压:无 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:0°C ~ 70°C 封装/外壳:8-DIP（0.300"，7.62mm） 包装:管件 产品目录页面:1316 (CN2011-ZH PDF) |
| L6730TR | 功能描述:DC/DC 开关控制器 Adjustable Step Down Controller RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| L6731B | 功能描述:开关变换器、稳压器与控制器 Adj. Step-Down w/ Synch Rectification RoHS:否 制造商:Texas Instruments 输出电压:1.2 V to 10 V 输出电流:300 mA 输出功率: 输入电压:3 V to 17 V 开关频率:1 MHz 工作温度范围: 安装风格:SMD/SMT 封装 / 箱体:WSON-8 封装:Reel |
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