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参数资料
| 型号： | LTC3786EMSE#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING CONTROLLER, 900 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封装： | LEAD FREE, PLASTIC, MSOP-16 |
| 文件页数： | 6/34页 |
| 文件大小： | 397K |
| 代理商： | LTC3786EMSE#PBF |
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LTC3786
14
3786fa
applicaTions inForMaTion
TheTypicalApplicationonthefirstpageisabasicLTC3786
applicationcircuit.LTC3786canbeconfiguredtouseeither
inductor DCR (DC resistance) sensing or a discrete sense
resistor (RSENSE) for current sensing. The choice between
the two current sensing schemes is largely a design trade-
off between cost, power consumption and accuracy. DCR
sensing is becoming popular because it does not require
current sensing resistors and is more power efficient,
especially in high current applications. However, current
sensing resistors provide the most accurate current limits
for the controller. Other external component selection is
driven by the load requirement, and begins with the se-
lection of RSENSE (if RSENSE is used) and inductor value.
Next, the power MOSFETs are selected. Finally, input and
output capacitors are selected.
SENSE+ and SENSE– Pins
The SENSE+ and SENSE– pins are the inputs to the cur-
rent comparators. The common mode input voltage range
of the current comparators is 2.5V to 38V. The current
sense resistor is normally placed at the input of the boost
controller in series with the inductor.
The SENSE+ pin also provides power to the current com-
parator. It draws ~200A during normal operation. There
is a small base current of less than 1A that flows into
the SENSE– pin. The high impedance SENSE– input to the
current comparators allows accurate DCR sensing.
Filter components mutual to the sense lines should be
placed close to the LTC3786, and the sense lines should
run close together to a Kelvin connection underneath the
current sense element (shown in Figure 1). Sensing cur-
rent elsewhere can effectively add parasitic inductance
and capacitance to the current sense element, degrading
the information at the sense terminals and making the
programmed current limit unpredictable. If DCR sensing
is used (Figure 2b), sense resistor R1 should be placed
closetotheswitchingnode,topreventnoisefromcoupling
into sensitive small-signal nodes.
Sense Resistor Current Sensing
A typical sensing circuit using a discrete resistor is shown
in Figure 2a. RSENSE is chosen based on the required
output current.
The current comparator has a maximum threshold
VSENSE(MAX) of 75mV. The current comparator threshold
sets the peak of the inductor current, yielding a maximum
average inductor current, IMAX, equal to the peak value
VIN
TO SENSE FILTER,
NEXT TO THE CONTROLLER
INDUCTOR OR RSENSE
3786 F01
(OPTIONAL)
VIN
VOUT
3786 F02a
TG
SW
BG
LTC3786
INTVCC
BOOST
SENSE+
SENSE–
VBIAS
SGND
TG
SW
BG
INDUCTOR
DCR
L
LTC3786
INTVCC
BOOST
SENSE+
SENSE–
R2
C1
VBIAS
VIN
VOUT
PLACE C1 NEAR SENSE PINS
SGND
3786 F02b
(R1||R2) C1 =
L
DCR
RSENSE(EQ) = DCR
R2
R1 + R2
R1
(2b) Using the Inductor DCR to Sense Current
(2a) Using a Resistor to Sense Current
Figure 2. Two Different Methods of Sensing Current
Figure 1. Sense Lines Placement with Inductor or Sense Resistor
相关PDF资料 |
PDF描述 |
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| LTC3786EUD#PBF | SWITCHING CONTROLLER, 900 kHz SWITCHING FREQ-MAX, PQCC16 |
| LTC3787IGN#TRPBF | SWITCHING CONTROLLER, 585 kHz SWITCHING FREQ-MAX, PDSO28 |
| LTC3787EGN#TRPBF | SWITCHING CONTROLLER, 585 kHz SWITCHING FREQ-MAX, PDSO28 |
| LTC3787EUFD#PBF | SWITCHING CONTROLLER, 585 kHz SWITCHING FREQ-MAX, PQCC28 |
| LTC3787IGN#PBF | SWITCHING CONTROLLER, 585 kHz SWITCHING FREQ-MAX, PDSO28 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3786EUD#PBF | 功能描述:IC REG CTRLR BST PWM CM 16-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 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 |
| LTC3786EUD#PBF | 制造商:Linear Technology 功能描述:IC, DC-DC CONV, 550kHz, QFN16 |
| LTC3786EUD#TRPBF | 功能描述:IC REG CTRLR BST PWM CM 16-QFN 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: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) |
| LTC3786IMSE#PBF | 功能描述:IC REG CTRLR BST PWM CM 16-MSOP 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: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) |
| LTC3786IMSE#TRPBF | 功能描述:IC REG CTRLR BST PWM CM 16-MSOP 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: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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