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参数资料
| 型号： | LT3741IUF#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING CONTROLLER, 1070 kHz SWITCHING FREQ-MAX, PQCC20 |
| 封装： | 4 X 4 MM, LEAD FREE, PLASTIC, MO-220WGGD-1, QFN-20 |
| 文件页数： | 4/24页 |
| 文件大小： | 243K |
| 代理商： | LT3741IUF#PBF |
LT3741
12
3741fb
OPERATION
The LT3741 utilizes xed-frequency, average current mode
control to accurately regulate the inductor current, inde-
pendently from the output voltage. This is an ideal solu-
tion for applications requiring a regulated current source.
The control loop will regulate the current in the inductor
at an accuracy of ±6%. Once the output has reached the
regulation voltage determined by the resistor divider from
the output to the FB pin and ground, the inductor current
will be reduced by the voltage regulation loop. In voltage
regulation, the output voltage has an accuracy of ±1.5%.
For additional operation information, refer to the Block
Diagram in Figure 1.
The current control loop has two reference inputs, deter-
mined by the voltage at the analog control pins, CTRL1 and
CTRL2. The lower of the two analog voltages on CTRL1
and CTRL2 determines the regulated output current. The
analog voltage at the CTRL1 pin is buffered and produces
a reference voltage across an internal resistor. The internal
buffer has a 1.5V clamp on the output, limiting the analog
control range of the CTRL1 and CTRL2 pins from 0V to
1.5V – corresponding to a 0mV to 51mV range on the
sense resistor, RS. The average current-mode control
loop uses the internal reference voltage to regulate the
inductor current, as a voltage drop across the external
sense resistor, RS.
A 2V reference voltage is provided on the VREF pin to al-
low the use of a resistor voltage divider to the CTRL1 and
CTRL2 pins. The VREF pin can supply up to 500μA and is
current limited to 1mA.
The error amplier for the average current-mode control
loop has a common mode lockout that regulates the induc-
tor current so that the error amplier is never operated out
of the common mode range. The common mode range is
from 0V to 2V below the VIN supply rail.
The overcurrent set point is equal to the regulated current
level set by the CTRL1 pin with an additional 23mV offset
between the SENSE+ and SENSE– pins. The overcurrent
is limited on a cycle-by-cycle basis; shutting switching
down once the overcurrent level is reached. Overcurrent
is not soft-started.
The regulated output voltage is set with a resistor divider
from the output back to the FB pin. The reference at the
FB pin is 1.21V. If the output voltage level is high enough
to engage the voltage loop, the regulated inductor current
will be reduced to support the load at the output. If the
voltage at the FB pin reaches 1.5V (~25% higher than
the regulation level), an internal overvoltage ag is set,
shutting down switching for 13μs.
The EN/UVLO pin functions as a precision shutdown
pin. When the voltage at the EN/UVLO pin is lower than
1.55V, the internal reset ag is asserted and switching is
terminated. Full shutdown occurs at approximately 0.5V
with a quiescent current of less than 1μA in full shutdown.
The EN/UVLO pin has 130mV of built-in hysteresis. In
addition, a 5.5μA current source is connected to this pin
that allows any amount of hysteresis to be added with a
series resistor or resistor divider from VIN.
During startup, the SS pin is held low until the internal
reset goes low. Once reset goes low, the capacitor at the
soft-start pin is charged with an 11μA current source.
The internal buffers for the CTRL1 and CTRL2 signals are
limited by the voltage at the soft-start pin, slowly ramping
the regulated inductor current to the current determined
by the voltage at the CTRL1 or CTRL2 pins.
The thermal shutdown is set at 163°C with 8°C hysteresis.
During thermal shutdown, all switching is terminated and
the part is in reset (forcing the SS pin low).
The switching frequency is determined by a resistor at
the RT pin. The RT pin is also limited to 60μA, while not
recommended, this limits the switching frequency to 2MHz
when the RT pin is shorted to ground. The LT3741 may
also be synchronized to an external clock through the use
of the SYNC pin.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3741IUF-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:High Power, Constant Current, Constant Voltage, Step-Down Controller |
| LT3742 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual, 2-Phase Step-Down Switching Controller |
| LT3742_1 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual, 2-Phase Step-Down Switching Controller Programmable Soft-Start |
| LT3742EUF#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
| LT3742EUF#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 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:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
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