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參數(shù)資料
| 型號： | LTC4064 |
| 廠商： | Linear Technology Corporation |
| 英文描述： | Monolithic Linear Charger for Back-Up Li-Ion Batteries |
| 中文描述： | 單片線性充電器作為備份鋰離子電池 |
| 文件頁數(shù)： | 9/16頁 |
| 文件大?。?/td> | 174K |
| 代理商： | LTC4064 |
LTC4064
9
4064f
For example, if 500mA charge current is required,
calculate:
R
PROG
= 1500V/0.5A = 3k
For best stability over temperature and time, 1% metal-
film resistors are recommended.
If the charger is in constant-temperature or constant-
voltage mode, the battery current can be monitored by
measuring the PROG pin voltage as follows:
I
BAT
= (V
PROG
/ R
PROG
) 1000
USB and Wall Adapter Power
Although the LTC4064 allows charging from a USB port,
a wall adapter can also be used to charge Li-Ion batteries.
Figure 2 shows an example of how to combine wall adapter
and USB power inputs. A P-channel MOSFET, MP1, is
used to prevent back conducting into the USB port when
a wall adapter is present and Schottky diode, D1, is used
to prevent USB power loss through the 1k pull-down
resistor.
Typically a wall adapter can supply significantly more
current than the 500mA-limited USB port. Therefore, an N-
channel MOSFET, MN1 and an extra 3k program resistor
can be used to increase the charge current to 1A when the
wall adapter is present.
APPLICATIU
Undervoltage Lockout (UVLO)
An internal undervoltage lockout circuit monitors the input
voltage and keeps the charger in shutdown mode until V
CC
rises above the undervoltage lockout threshold. The UVLO
circuit has a built-in hysteresis of 200mV. Furthermore, to
protect against reverse current in the power MOSFET, the
UVLO circuit keeps the charger in shutdown mode if V
CC
falls to within 35mV of the battery voltage. If the UVLO
comparator is tripped, the charger will not come out of
shutdown until V
CC
rises 70mV above the battery voltage.
W
U
U
Trickle Charge And Defective Battery Detection
At the beginning of a charge cycle, if the battery voltage is
low (below 2.48V) the charger goes into trickle charge
reducing the charge current to 10% of the full-scale
current. If the low battery voltage persists for one quarter
of the total charge time, the battery is assumed to be
defective, the charge cycle is terminated, the CHRG pin
output assumes a high impedance state, and the FAULT
pin pulls low. The fault can be cleared by toggling V
CC
,
temporarily forcing the SHDN pin to 0V, or temporarily
forcing the BAT pin voltage above 2.48V.
Shutdown
The LTC4064 can be shut down (I
CC
= 25
μ
A) by pulling the
SHDN pin to 0V. For normal operation, pull the SHDN pin
above the manual shutdown threshold voltage level. Do
not leave this pin open. In shutdown the internal linear
regulator is turned off, and the internal timer is reset.
Programming Charge Current
The formula for the battery charge current (see Figure 1)
is:
I
CHG
= (I
PROG
) 1000
= (1.5V / R
PROG
) 1000 or
R
PROG
= 1500V/I
CHG
where R
PROG
is the total resistance from the PROG pin to
ground. Under trickle charge conditions, this current is
reduced to 10% of the full-scale value.
Figure 2. Combining Wall Adapter and USB Power
4064
F02
1k
3k
Li-Ion
BATTERY
5V WALL
ADAPTER
1A I
CHG
3k
LTC4064
BAT
V
CC
2
9
7
I
CHG
PROG
+
SYSTEM
LOAD
USB
POWER
500mA I
CHG
D1
MN1
MP1
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| LTC4064EMSE | 功能描述:IC CHARGER BATT L-ION 4V 10-MSOP RoHS:否 類別: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 安裝類型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC4064EMSE#PBF | 功能描述:IC CHARGER BATT L-ION 4V 10-MSOP RoHS:是 類別: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 安裝類型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC4064EMSE#TR | 功能描述:IC CHARGER BATT L-ION 4V 10-MSOP RoHS:否 類別: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 安裝類型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC4064EMSE#TRPBF | 功能描述:IC CHARGER BATT L-ION 4V 10-MSOP RoHS:是 類別: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 安裝類型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC4065 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Standalone 750mA Li-Ion Battery Charger in 2 】 2 DFN |
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