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参数资料
| 型号： | LT2940CDD#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 电源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO12 |
| 封装： | 3 X 3 MM, LEAD FREE, PLASTIC, DFN-12 |
| 文件页数： | 2/24页 |
| 文件大小： | 337K |
| 代理商： | LT2940CDD#PBF |
LT2940
10
2940f
APPLICATIONS INFORMATION
Introduction
The LT2940 power and current monitor brings together
circuits necessary to measure, monitor and control power.
In circuits where voltage is constant, power is directly
proportional to current. The LT2940 enables power moni-
toring and control in applications where both the current
and the voltage may be variable due to supply voltage
uncertainty, component parametric changes, transient
conditions, time-varying signals, and so forth.
The LT2940’s four-quadrant multiplier calculates in-
stantaneous power from its voltage sense and current
sense inputs. Its output driver sources and sinks cur-
rent proportional to power (magnitude and direction),
which affords exible voltage scaling, simple ltering
and, into a reference, bipolar signals. Its onboard
comparator is the nal piece required for integrated
power monitoring. In addition, the LT2940 provides a
proportional-to-current output that allows for equally
straightforward scaling, ltering and monitoring of the
sensed current.
Please note: although standard convention denes cur-
rents as positive going into a pin (as is generally the case
in the Electrical Characteristics table), the opposite is
true of the PMON and IMON pins. Throughout this data
sheet the power and current monitor output currents
are dened positive coming out of PMON and IMON,
respectively. Adopting this convention lets positive voltage
differences at the current and voltage sense pins yield
positive currents sourced from PMON and IMON that
can be scaled to positive ground referenced voltages
with a resistor.
Multiplier Operation
The LT2940 power and current monitor contains a four-
quadrant multiplier designed to measure the voltage and
current of a generator or load, and output signals propor-
tional to power and current. Figure 1 shows a signal path
block diagram. The operating ranges of the voltage sense
and current sense inputs are included. To simplify the
notation, the differential input voltages are dened as:
VV = VV+ – VV–
(1a)
VI = VI+ – VI–
(1b)
The full scale output of the multiplier core is ±0.4V2, which
the PMON output driver converts to current through a
scale factor of KPMON.
IPMON = KPMON VV VI
(2)
K
A
V
PMON = 500
2
(3)
The voltage across the current sense input pins is converted
to a current by the IMON output driver through the scale
factor of GIMON.
IIMON = GIMON VI
(4)
G
A
V
IMON = 1000
(5)
Both the PMON and IMON outputs reach full-scale at
±200μA.
The headroom and compliance limits for the input and
output pins are summarized in Table 1 for easy reference.
It is important to note that the current sense inputs, I+
and I–, operate over a 4V to 80V range completely inde-
pendent of the LT2940’s supply pin, VCC. Note also that
the inputs accept signals of either polarity, and that the
Figure 1. LT2940 Signal Path Diagram
LT2940
VI = VI+ – VI–
±200mV (MAX)
2940 F01
±200μA
FULL-SCALE
7
8
11 10
PMON
V +
V –
I +
I –
VV VI = ±0.4V
2 FULL-SCALE
4
KPMON = 500
V2
μA
±200μA
FULL-SCALE
IMON
5
GIMON = 1000
V
μA
VV = VV+ – VV–
±8V (MAX)
+
–
+
–
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT2940CMS | 制造商:LINER 制造商全称:Linear Technology 功能描述:Power and Current Monitor |
| LT2940CMS#PBF | 功能描述:IC CURRENT/POWER MONITOR 12MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 电源管理 - 专用 系列:- 标准包装:1 系列:- 应用:手持/移动设备 电流 - 电源:- 电源电压:3 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:14-WFDFN 裸露焊盘 供应商设备封装:14-LLP-EP（4x4） 包装:Digi-Reel® 配用:LP3905SD-30EV-ND - BOARD EVALUATION LP3905SD-30 其它名称:LP3905SD-30DKR |
| LT2940CMS#PBF | 制造商:Linear Technology 功能描述:IC POWER AND CURRENT MONITOR MSOP-12 |
| LT2940CMS#TRPBF | 功能描述:IC POWER/CURRENT MONITOR 12MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 电源管理 - 专用 系列:- 标准包装:1 系列:- 应用:手持/移动设备 电流 - 电源:- 电源电压:3 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:14-WFDFN 裸露焊盘 供应商设备封装:14-LLP-EP（4x4） 包装:Digi-Reel® 配用:LP3905SD-30EV-ND - BOARD EVALUATION LP3905SD-30 其它名称:LP3905SD-30DKR |
| LT2940CMSPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Power and Current Monitor |
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