參數(shù)資料
型號(hào): LTC4007EUFD-1#PBF
廠商: LINEAR TECHNOLOGY CORP
元件分類: 穩(wěn)壓器
英文描述: 4A, High Efficiency, Standalone Li-Ion Battery Charger; Package: QFN; No of Pins: 24; Temperature Range: -40°C to +125°C
中文描述: BATTERY CHARGE CONTROLLER, 345 kHz SWITCHING FREQ-MAX, PQCC24
封裝: 4 X 5 MM, LEAD FREE, PLASTIC, QFN-24
文件頁數(shù): 6/24頁
文件大?。?/td> 269K
代理商: LTC4007EUFD-1#PBF
14
LTC4007-1
40071f
APPLICATIO S I FOR ATIO
WU
UU
Battery Detection
It is generally not good practice to connect a battery while
the charger is running. The timer is in an unknown state
and the charger could provide a large surge current into
the battery for a brief time. The Figure 5 circuit keeps the
charger shut down and the timer reset while a battery is not
connected.
Charging current can be programmed by pulse width
modulating RPROG with a switch Q1 to RPROG at a fre-
quency higher than a few kHz (Figure 6). CPROG must be
increased to reduce the ripple caused by the RPROG
switching. The compensation capacitor at ITH will prob-
ably need to be increased also to improve stability and
prevent large overshoot currents during start-up condi-
tions. Charging current will be proportional to the duty
cycle of the switch with full current at 100% duty cycle and
zero current when Q1 is off.
Maintaining C/10 Accuracy
The C/10 comparator threshold that drives the FLAG pin
has a fixed threshold of approximately VPROG = 400mV.
This threshold works well when RPROG is 26.7k, but will
not yield a 10% charging current indication if RPROG is a
different value. There are situations where a standard
value of RSENSE will not allow the desired value of charging
current when using the preferred RPROG value. In these
cases, where the full-scale voltage across RSENSE is within
±20mV of the 100mV full-scale target, the input resistors
connected to CSP and BAT can be adjusted to provide the
desired maximum programming current as well as the
correct FLAG trip point.
For example, the desired max charging current is 2.5A but
the best RSENSE value is 0.033. In this case, the voltage
across RSENSE at maximum charging current is only
82.5mV, normally RPROG would be 30.1k but the nominal
FLAG trip point is only 5% of maximum charging current.
If the input resistors are reduced by the same amount as
23 DCIN
LTC4007-1
ADAPTER
POWER
SWITCH CLOSED
WHEN BATTERY
CONNECTED
22 SHDN
40071 F05
Figure 5
Charger Current Programming
The basic formula for charging current is:
I
Vk
R
V
R
CHARGE MAX
REF
PROG
SENSE
()
.
/
– .
=
3 01
0 035
VREF = 1.19V
This leaves two degrees of freedom: RSENSE and RPROG.
The 3.01k input resistors must not be altered since internal
currents and voltages are trimmed for this value. Pick
RSENSE by setting the average voltage between CSP and
BAT to be close to 100mV during maximum charger
current. Then RPROG can be determined by solving the
above equation for RPROG.
R
Vk
RI
V
PROG
REF
SENSE
CHARGE MAX
=
+
.
()
301
0 035
Table 2. Recommended RSNS and RPROG Resistor Values
IMAX (A)
RSENSE () 1%
RSENSE (W)
RPROG (k) 1%
1.0
0.100
0.25
26.7
2.0
0.050
0.25
26.7
3.0
0.033
0.5
26.7
4.0
0.025
0.5
26.7
Figure 6. PWM Current Programming
RZ
102k
CPROG
40071 F06
PROG
9
LTC4007-1
Q1
2N7002
RPROG
0V
5V
相關(guān)PDF資料
PDF描述
LTC4007EUFD-1#TRPBF 4A, High Efficiency, Standalone Li-Ion Battery Charger; Package: QFN; No of Pins: 24; Temperature Range: -40°C to +125°C
LTC4008EGN#PBF 4A, High Efficiency, Multi-Chemistry Battery Charger; Package: SSOP; No of Pins: 20; Temperature Range: -40°C to +125°C
LTC4008EGN#TRPBF 4A, High Efficiency, Multi-Chemistry Battery Charger; Package: SSOP; No of Pins: 20; Temperature Range: -40°C to +125°C
LTC4008EGN-1#PBF 4A, High Efficiency, Multi-Chemistry Battery Charger; Package: SSOP; No of Pins: 20; Temperature Range: -40°C to +125°C
LTC4008EGN-1#TRPBF 4A, High Efficiency, Multi-Chemistry Battery Charger; Package: SSOP; No of Pins: 20; Temperature Range: -40°C to +125°C
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參數(shù)描述
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LTC4008EGN#TR 功能描述:IC CTRLR CHARGR PWM CC/CV 20SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- 功能:電池監(jiān)控器 電池化學(xué):堿性,鋰離子,鎳鎘,鎳金屬氫化物 電源電壓:1 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-6 供應(yīng)商設(shè)備封裝:SOT-6 包裝:帶卷 (TR)
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