参数资料
| 型号： | LTC4080EMSE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 13/20页 |
| 文件大小： | 0K |
| 描述： | IC CHARGER LI-ION 10-MSOP |
| 标准包装： | 2,500 |
| 功能： | 充电管理 |
| 电池化学： | 锂离子（Li-Ion） |
| 电源电压： | 3.75 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 |
| 供应商设备封装： | 10-MSOP 裸露焊盘 |
| 包装： | 带卷 (TR) |
LTC4080
OPERATIO
from zero to full-scale current over a period of approximately
180μs. This has the effect of minimizing the transient cur-
rent load on the power supply during start-up.
Timer and Recharge
The LTC4080’s battery charger has an internal termina-
tion timer that starts when the input voltage is greater
than the undervoltage lockout threshold and at least
80mV above BAT, and the battery charger is leaving
shutdown.
At power-up or when exiting shutdown, the charge time
is set to 4.5 hours. Once the charge cycle terminates, the
battery charger continuously monitors the BAT pin voltage
using a comparator with a 2ms ?lter time. When the aver-
age battery voltage falls below 4.1V (which corresponds
to 80%-90% battery capacity), a new charge cycle is initi-
ated and a 2.25 hour timer begins. This ensures that the
battery is kept at, or near, a fully charged condition and
eliminates the need for periodic charge cycle initiations.
The ? C ? H ? R ? G output assumes a strong pulldown state dur-
ing recharge cycles until C/10 is reached or the recharge
cycle terminates.
SWITCHING REGULATOR OPERATION:
The switching regulator in the LTC4080 can be turned on
by pulling the EN_BUCK pin above V IH . It has two user-
selectable modes of operation: constant-frequency (PWM)
mode and Burst Mode Operation. The constant-frequency
mode operation offers low noise at the expense of ef?-
ciency whereas the Burst Mode operation offers increased
ef?ciency at light loads at the cost of increased noise and
output voltage ripple. A detailed description of different
operating modes and different aspects of operation fol-
low. Operations can best be understood by referring to
the Block Diagram.
Constant-Frequency (PWM) Mode Operation
The switching regulator operates in constant-frequency
(PWM) mode when the MODE pin is pulled below V IL . In
this mode, it uses a current mode architecture including
an oscillator, an error ampli?er, and a PWM comparator
for excellent line and load regulation. The main switch
MP2 (P-channel MOSFET) turns on to charge the inductor
at the beginning of each clock cycle if the FB pin voltage
is less than the 0.8V reference voltage. The current into
the inductor (and the load) increases until it reaches the
peak current demanded by the error amp. At this point,
the main switch turns off and the synchronous switch
MN1 (N-channel MOSFET) turns on allowing the inductor
current to ?ow from ground to the load until either the
next clock cycle begins or the current reduces to the zero
current (I ZERO ) level.
Oscillator : In constant-frequency mode, the switching
regulator uses a dedicated oscillator which runs at a
?xed frequency of 2.25MHz. This frequency is chosen to
minimize possible interference with the AM band.
Error Ampli?er : The error ampli?er is an internally com-
pensated transconductance (g m ) ampli?er with a g m
of 65 μmhos. The internal 0.8V reference voltage is
compared to the voltage at the FB pin to generate a
current signal at the output of the error ampli?er. This
current signal is then converted into a voltage signal
(I TH ), and represents the peak inductor current required
to achieve regulation.
PWM Comparator : Lossless current sensing converts the
PMOS switch current signal to a voltage which is summed
with the internal slope compensation signal. The PWM
comparator compares this summed signal to I TH and
determines when to turn off the main switch. The switch
current sensing is blanked for ~12ns at the beginning of
each clock cycle to prevent false switch turn-off.
Burst Mode Operation
Burst Mode operation can be selected by pulling the
MODE pin above V IH . In this mode, the internal oscil-
lator is disabled, the error ampli?er is converted into a
comparator monitoring the FB voltage, and the inductor
current swings between a ?xed I PEAK (~80mA) and I ZERO
(35mA) irrespective of the load current as long as the FB
pin voltage is less than or equal to the reference voltage
of 0.8V. Once V FB is greater than 0.8V, the control logic
shuts off both switches along with most of the circuitry
and the regulator is said to enter into SLEEP mode. In
SLEEP mode, the regulator only draws about 20μA from
the BAT pin provided that the battery charger is turned
off. When the output voltage droops about 1% from its
4080fb
13
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC4080X | 制造商:LINER 制造商全称:Linear Technology 功能描述:500mA Standalone Li-Ion Charger with Integrated 300mA Synchronous Buck in 3mm × 3mm DFN |
| LTC4080XEDD#PBF | 功能描述:IC CHARGER LI-ION 10-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:61 系列:- 功能:电源管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:4.35 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:22-WFDFN 裸露焊盘 供应商设备封装:22-DFN（6x3）裸露焊盘 包装:管件 |
| LTC4080XEDD#TRPBF | 功能描述:IC CHARGER LI-ION 10-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:61 系列:- 功能:电源管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:4.35 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:22-WFDFN 裸露焊盘 供应商设备封装:22-DFN（6x3）裸露焊盘 包装:管件 |
| LTC4080XEDD-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:500mA Standalone Li-Ion Charger with Integrated 300mA Synchronous Buck in 3mm × 3mm DFN |
| LTC4080XEDD-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:500mA Standalone Li-Ion Charger with Integrated 300mA Synchronous Buck in 3mm × 3mm DFN |
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