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参数资料
| 型号： | LTC3109EUF#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 0.026 A SWITCHING REGULATOR, 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： | 329K |
| 代理商： | LTC3109EUF#PBF |
LTC3109
3109f
applicaTions inForMaTion
INTRODUCTION
The LTC3109 is designed to gather energy from very low
input voltage sources and convert it to usable output
voltages to power microprocessors, wireless transmit-
ters and analog sensors. Its architecture is specifically
tailored to applications where the input voltage polarity is
unknown, or can change. This “auto-polarity” capability
makes it ideally suited to energy harvesting applications
using a TEG whose temperature differential may be of
either polarity.
Applications such as wireless sensors typically require
much more peak power, and at higher voltages, than
the input voltage source can produce. The LTC3109 is
designed to accumulate and manage energy over a long
period of time to enable short power pulses for acquiring
and transmitting data. The pulses must occur at a low
enough duty cycle that the total output energy during the
pulsedoesnotexceedtheaveragesourcepowerintegrated
over the accumulation time between pulses. For many
applications, this time between pulses could be seconds,
minutes or hours.
The PGOOD signal can be used to enable a sleeping
microprocessor or other circuitry when VOUT reaches
regulation, indicating that enough energy is available for
a transmit pulse.
INPUT VOLTAGE SOURCES
The LTC3109 can operate from a number of low input
voltage sources, such as Peltier cells (thermoelectric
generators), or low level AC sources. The minimum input
voltage required for a given application will depend on the
transformer turns ratios, the load power required, and the
internal DC resistance (ESR) of the voltage source. Lower
ESRsourceswillallowoperationfromlowerinputvoltages,
and provide higher output power capability.
For a given transformer turns ratio, there is a maximum
recommended input voltage to avoid excessively high
secondary voltages and power dissipation in the shunt
regulator. It is recommended that the maximum input
voltage times the turns ratio be less than 50.
Note that a low ESR decoupling capacitor may be required
acrossaDCinputsourcetopreventlargevoltagedroopand
ripple caused by the source’s ESR and the peak primary
switchingcurrent(whichcanreachhundredsofmilliamps).
Since the input voltage may be of either polarity, a ceramic
capacitor is recommended.
PELTIER CELL (THERMOELECTRIC GENERATOR)
A Peltier cell is made up of a large number of series-con-
nected P-N junctions, sandwiched between two parallel
ceramic plates. Although Peltier cells are often used as
coolers by applying a DC voltage to their inputs, they will
alsogenerateaDCoutputvoltage,usingtheSeebeckeffect,
when the two plates are at different temperatures.
When used in this manner, they are referred to as thermo-
electricgenerators(TEGs).Thepolarityoftheoutputvoltage
will depend on the polarity of the temperature differential
between the TEG plates. The magnitude of the output volt-
age is proportional to the magnitude of the temperature
differential between the plates.
The low voltage capability of the LTC3109 design allows it
tooperatefromatypicalTEGwithtemperaturedifferentials
as low as 1°C of either polarity, making it ideal for harvest-
ing energy in applications where a temperature difference
exists between two surfaces or between a surface and
the ambient temperature. The internal resistance (ESR)
of most TEGs is in the range of 1Ω to 5Ω, allowing for
reasonablepowertransfer.ThecurvesinFigure2showthe
open-circuit output voltage and maximum power transfer
for a typical TEG with an ESR of 2Ω, over a 20°C range of
temperature differential (of either polarity).
dT (°C)
1
TEG
V
OPEN-CIRCUIT
(mV)
TEG
MAXIMUM
P
OUT
–
IDEAL
(mW)
10
100
1000
0.1
1
10
100
10
100
3109 F02
TEG: 30mm SQUARE
127 COUPLES
R = 2
VOC
MAX POUT
(IDEAL)
Figure 2. Typical Performance of a Peltier Cell
Acting as a Power Generator (TEG)
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3109EUF-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Auto-Polarity, Ultralow Voltage Step-Up Converter and Power Manager |
| LTC3109IGN#PBF | 功能描述:IC BOOST CONVERTER PMU 20SSOP 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 |
| LTC3109IGN#TRPBF | 功能描述:IC BOOST CONVERTER PMU 20SSOP 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 |
| LTC3109IGN-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Auto-Polarity, Ultralow Voltage Step-Up Converter and Power Manager |
| LTC3109IGN-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Auto-Polarity, Ultralow Voltage Step-Up Converter and Power Manager |
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