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參數(shù)資料
| 型號： | LTC1734 |
| 廠商： | Linear Technology Corporation |
| 英文描述： | Lithium-Ion Linear Battery Charger in SOT-23(鋰離子線性電池充電器（SOT-23封裝）) |
| 中文描述： | 鋰離子線性電池充電器采用SOT - 23（鋰離子線性電池充電器（采用SOT - 23封裝）） |
| 文件頁數(shù)： | 5/8頁 |
| 文件大?。?/td> | 140K |
| 代理商： | LTC1734 |
5
LTC1734
OPERATIOU
When V
CC
is applied, the charger can be manually shut
down by floating the otherwise grounded end of R
PROG
.
An internal 3
μ
A current source pulls the PROG pin above
the 2.15V threshold of voltage comparator C1 initiating
shutdown.
For charging NiMH or NiCd batteries, the LTC1734 can be
turned into a constant current source by grounding the
BAT pin. This will prevent amplifier A1 from trying to limit
charging current and only A2 will control the current.
APPLICATIO
S I
FOR
ATIO
U
Charging Operation
Charging begins when an input voltage is present that
exceeds the undervoltage lockout threshold (V
UVLOI
), a
Li-Ion battery is connected to the charger output and a
program resistor is connected from the PROG pin to
ground. During the first portion of the charge cycle, when
the battery voltage is below the preset float voltage, the
charger is in the constant current mode. As the battery
voltage rises and approaches the preset float voltage, the
charge current begins to decrease and the constant
voltage portion of the charge cycle begins. The charge
current will continue to decrease exponentially as the
battery approaches a fully charged condition.
Should the battery be removed during charging, a built-in
protection circuit will prevent BAT from rising above 5V.
W
U
U
Fault conditions such as overheating of the die or exces-
sive PNP base current drive are monitored and limited.
When input power is removed or manual shutdown is
entered, the charger will drain only tiny leakage currents
from the battery, thus maximizing battery standby time.
With V
CC
removed the external PNP’s base is connected to
the battery by the charger. In manual shutdown the base
is connected to V
CC
by the charger.
Manual Shutdown
Floating the program resistor shuts down the charger. In
this mode, a small current is drawn from the supply (I
SMS
)
while only a negligible leakage current is delivered to the
battery load (I
BMS
).
Sleep Mode
When the input supply is disconnected, the IC enters the
sleep mode. In this mode, the battery drain current (I
BSL
)
is a negligible leakage current, allowing the battery to
remain connected to the charger for an extended period of
time without discharging the battery. The leakage current
is due to the reverse-biased B-E junction of the external
PNP transistor.
Undervoltage Lockout
Undervoltage lockout (UVLO) keeps the charger off until
the input voltage exceeds a predetermined threshold level
(V
UVLOI
) of 4.56V. Approximately 150mV of hysteresis is
built in to prevent oscillation around the threshold level. In
undervoltage lockout, battery drain current is very low
(<1
μ
A).
Programming Constant Current
When in the constant current mode, the full-scale current
is programmed using a single external resistor between
the PROG pin and ground. The charge current will be 1000
times greater than the current through the program
resistor. The program resistor value is selected by divid-
ing the voltage forced across the resistor (1.5V) by the
desired resistor current. Different charge currents can be
programmed using a DAC, or using a PWM output from
a microcontroller or by switching in different program
resistors.
The LTC1734 is designed for a maximum current of
approximately 700mA. This translates to a maximum
PROG pin current of 700
μ
A and a minimum program
resistor of approximately 2.1k. Because the PROG pin is in
a closed-loop signal path, the pole frequency must be kept
high enough to maintain adequate AC stability. See the
Stability section for more details.
Monitoring Charge Current
The voltage on the PROG pin indicates the charge current
as a proportion of the maximum current set by the
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相關代理商/技術參數(shù) |
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| LTC1734ES6-4.1#TR | 功能描述:IC BATT CHRGR LI-ION LIN SOT23-6 RoHS:否 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 標準包裝:61 系列:- 功能:電源管理 電池化學:鋰離子（Li-Ion）、鋰聚合物（Li-Pol） 電源電壓:4.35 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤 供應商設備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC1734ES6-4.1#TRM | 功能描述:IC BATT CHRGR LI-ION LIN SOT23-6 RoHS:否 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 標準包裝:61 系列:- 功能:電源管理 電池化學:鋰離子（Li-Ion）、鋰聚合物（Li-Pol） 電源電壓:4.35 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤 供應商設備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC1734ES6-4.1#TRMPBF | 功能描述:IC BATT CHRGR LI-ION LIN SOT23-6 RoHS:是 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 標準包裝:61 系列:- 功能:電源管理 電池化學:鋰離子（Li-Ion）、鋰聚合物（Li-Pol） 電源電壓:4.35 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤 供應商設備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC1734ES6-4.1#TRPBF | 功能描述:IC BATT CHRGR LI-ION LIN SOT23-6 RoHS:是 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 標準包裝:61 系列:- 功能:電源管理 電池化學:鋰離子（Li-Ion）、鋰聚合物（Li-Pol） 電源電壓:4.35 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤 供應商設備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC1734ES6-4.2 | 制造商:Linear Technology 功能描述:Battery Charger Li-Ion/NiCD/NiMH 200mA to 700mA 4.2V 6-Pin TSOT-23 制造商:Linear Technology 功能描述:0.9 A BATTERY CHARGE CONTROLLER, PDSO6 |
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