參數(shù)資料
型號(hào)： LTC4008EGN#TRPBF
廠商： LINEAR TECHNOLOGY CORP
元件分類(lèi)： 穩(wěn)壓器
英文描述： 4A, High Efficiency, Multi-Chemistry Battery Charger; Package: SSOP; No of Pins: 20; Temperature Range: -40°C to +125°C
中文描述： BATTERY CHARGE CONTROLLER, 345 kHz SWITCHING FREQ-MAX, PDSO20
封裝： 0.150 INCH, LEAD FREE, PLASTIC, SSOP-20
文件頁(yè)數(shù)： 2/24頁(yè)
文件大?。?/td> 221K
代理商： LTC4008EGN#TRPBF
LTC4008
10
4008fb
OPERATION
Input FET (LTC4008)
The input FET circuit performs two functions. It enables
the charger if the input voltage is higher than the CLP
pin and provides the logic indicator of AC present on the
ACP/SHDN pin. It controls the gate of the input FET to
keep a low forward voltage drop when charging and also
prevents reverse current ow through the input FET.
If the input voltage is less than VCLP, it must go at least
170mV higher than VCLN to activate the charger. When this
occurs the ACP/SHDN pin is released and pulled up with
an external load to indicate that the adapter is present.
The gate of the input FET is driven to a voltage sufcient
to keep a low forward voltage drop from drain to source.
If the voltage between DCIN and CLP drops to less than
25mV, the input FET is turned off slowly. If the voltage
between DCIN and CLP is ever less than –25mV, then
the input FET is turned off in less than 10μs to prevent
signicant reverse current from owing in the input FET.
In this condition, the ACP/SHDN pin is driven low and the
charger is disabled.
Input FET (LTC4008-1)
The input FET circuit is disabled for the LTC4008-1. There
is no low current shutdown mode when DCIN falls below
the CLP pin. The ACP/SHDN pin functions only to shut
down the charger.
Battery Charger Controller
The LTC4008 charger controller uses a constant off-time,
current mode step-down architecture. During normal
operation, the top MOSFET is turned on each cycle when
the oscillator sets the SR latch and turned off when the
main current comparator ICMP resets the SR latch. While
the top MOSFET is off, the bottom MOSFET is turned on
until either the inductor current trips the current compara-
tor IREV or the beginning of the next cycle. The oscillator
uses the equation:
t
VV
Vf
OFF
DCIN
BAT
DCIN
OSC
=
–
to set the bottom MOSFET on time. This activity is dia-
grammed in Figure 1.
The peak inductor current, at which ICMP resets the SR
latch, is controlled by the voltage on ITH. ITH is in turn
controlled by several loops, depending upon the situation
at hand. The average current control loop converts the
voltage between CSP and BAT to a representative cur-
rent. Error amp CA2 compares this current against the
desired current programmed by RPROG at the PROG pin
and adjusts ITH until:
V
R
VV
A
k
REF
PROG
CSP
BAT
=
+μ
Ω
–.
.
.
11 67
3 01
301
therefore,
I
V
R
A
k
R
CHARGE MAX
REF
PROG
SENSE
()
–.
.
=μ
Ω
11 67
301
The voltage at BATMON is divided down by an external
resistor divider and is used by error amp EA to decrease
ITH if the divider voltage is above the 1.19V reference.
When the charging current begins to decrease, the voltage
at PROG will decrease in direct proportion. The voltage at
PROG is then given by:
VI
R
A
k
R
k
PROG
CHARGE
SENSE
PROG
=+
μ
Ω
()
Ω
.
.
.
11 67
3 01
301
The accuracy of VPROG will range from 0% to ITOL.
VPROG is plotted in Figure 2.
The amplier CL1 monitors and limits the input current,
normally from the AC adapter to a preset level (100mV/RCL).
At input current limit, CL1 will decrease the ITH voltage,
thereby reducing charging current. The ICL indicatoroutput
will go low when this condition is detected and the FLAG
indicator will be inhibited if it is not already low.
TGATE
OFF
ON
BGATE
INDUCTOR
CURRENT
tOFF
TRIP POINT SET BY ITH VOLTAGE
ON
OFF
4008 F01
Figure 1
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LTC4009 制造商:LINER 制造商全稱(chēng):Linear Technology 功能描述:High Voltage High Current Controller for Battery Charging and Power Management
LTC4009-1 制造商:LINER 制造商全稱(chēng):Linear Technology 功能描述:High Effi ciency, Multi-Chemistry Battery Charger
LTC4009-2 制造商:LINER 制造商全稱(chēng):Linear Technology 功能描述:High Effi ciency, Multi-Chemistry Battery Charger
LTC4009CUF#PBF 功能描述:IC CHARGER BATTERY MC 20-QFN RoHS:是 類(lèi)別:集成電路 (IC) >> PMIC - 電池管理 系列:- 其它有關(guān)文件:STC3100 View All Specifications 特色產(chǎn)品:STC3100 - Battery Monitor IC 標(biāo)準(zhǔn)包裝:4,000 系列:- 功能:燃料，電量檢測(cè)計(jì)/監(jiān)控器 電池化學(xué):鋰離子（Li-Ion） 電源電壓:2.7 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類(lèi)型:表面貼裝 封裝/外殼:8-TSSOP，8-MSOP（0.118"，3.00mm 寬） 供應(yīng)商設(shè)備封裝:8-MiniSO 包裝:帶卷 (TR) 其它名稱(chēng):497-10526-2
LTC4009CUF#TRPBF 功能描述:IC CHARGER BATTERY MC 20-QFN RoHS:是 類(lèi)別:集成電路 (IC) >> PMIC - 電池管理 系列:- 標(biāo)準(zhǔn)包裝:61 系列:- 功能:電源管理 電池化學(xué):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(lèi)型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤(pán) 供應(yīng)商設(shè)備封裝:22-DFN（6x3）裸露焊盤(pán) 包裝:管件
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