参数资料
| 型号： | LTC3786EUD#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 14/34页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BST PWM CM 16-QFN |
| 标准包装： | 121 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 850kHz |
| 占空比： | 100% |
| 电源电压： | 4.5 V ~ 38 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： | 16-WFQFN 裸露焊盘 |
| 包装： | 管件 |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页当前第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页
LTC3786
APPLICATIONS INFORMATION
The Typical Application on the first page is a basic LTC3786
application circuit. LTC3786 can be configured to use either
inductor DCR (DC resistance) sensing or a discrete sense
resistor (R SENSE ) 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 R SENSE (if R SENSE 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 ~200μA during normal operation. There
is a small base current of less than 1μA 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
close to the switching node, to prevent noise from coupling
into sensitive small-signal nodes.
Sense Resistor Current Sensing
A typical sensing circuit using a discrete resistor is shown
in Figure 2a. R SENSE is chosen based on the required
output current.
The current comparator has a maximum threshold
V SENSE(MAX) of 75mV. The current comparator threshold
sets the peak of the inductor current, yielding a maximum
average inductor current, I MAX , equal to the peak value
TO SENSE FILTER,
NEXT TO THE CONTROLLER
V IN
INDUCTOR OR R SENSE 3786 F01
Figure 1. Sense Lines Placement with Inductor or Sense Resistor
VBIAS
SENSE +
V IN
VBIAS
SENSE +
V IN
SENSE –
INTV CC
LTC3786
(OPTIONAL)
SENSE –
INTV CC
LTC3786
C1
R2
R1
DCR
L
INDUCTOR
BOOST
TG
BOOST
TG
SW
V OUT
SW
V OUT
BG
SGND
3786 F02a
BG
SGND
3786 F02b
PLACE C1 NEAR SENSE PINS (R1||R2) ? C1 =
L
DCR
R SENSE(EQ) = DCR ?
R2
R1 + R2
(2a) Using a Resistor to Sense Current
(2b) Using the Inductor DCR to Sense Current
Figure 2. Two Different Methods of Sensing Current
3786fa
14
相关PDF资料 |
PDF描述 |
|---|---|
| LTC3787EUFD#PBF | IC REG CTRLR BST PWM CM 28-QFN |
| LTC3788IUH#TRPBF | IC REG CTRLR BST PWM CM 32-QFN |
| LTC3789EGN#PBF | IC REG CTRLR BST PWM CM 28-SSOP |
| LTC3801BES6#TRM | IC REG CTRLR BUCK PWM TSOT23-6 |
| LTC3802EGN | IC REG CTRLR BUCK PWM VM 28-SSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| 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) |
| LTC3786IUD#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:- 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) |
| LTC3786IUD#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) |
| LTC3787EGN#PBF | 功能描述:IC REG CTRLR BST PWM CM 28-SSOP 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 |
发布紧急采购，3分钟左右您将得到回复。