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參數(shù)資料
| 型號： | SC802 |
| 廠商： | Semtech Corporation |
| 英文描述： | Fully Integrated Lithium-Ion Battery Charger System with Timer |
| 中文描述： | 完全集成的鋰離子電池充電器系統(tǒng)的計時器 |
| 文件頁數(shù)： | 9/16頁 |
| 文件大?。?/td> | 484K |
| 代理商： | SC802 |
9
2005 Semtech Corp.
www.semtech.com
SC802/SC802A
POWER MANAGEMENT
PRELIMINARY
perature returns to the valid range the SC802 automati-
cally resumes the charge cycle. The charge timer will
time-out when the SC802 output on-time exceeds the
timer setting regardles of how long it has been disabled
due to temperature. The internal NTC thresholds of 30%
and 75% VCC were designed to work with curve-2 type
thermistors available from numerous vendors.
Design Example based on the typical application sche-
matic of page 1 using a Curve 2 Vishay-Dale NTC.
Thot = 50
o
C
Tcold = 0
o
C
Find R3 and RT1
Step 1: Pick an RT1 value high enough to prevent self-
heating.
(
V(RT1)
RT1
≥
)
DC
2
In general lower values of RT1 provide more noise for
the NTC voltage at the expense of bias current from the
input adapter. The dissipation constant DC is the power
rating of the NTC resulting in a 1
o
C self heating error.
The DC value for this NTC is 3mW and the voltage across
the NTC is 2.5V for a 5V adapter. Therefore RT1 > 2k.
Set RT1 = 10k
Step 2: Find R3 to set the correct Hot level trip point
9.52k
R
R
R
2.33
R3
T25
T50
T25
=
×
×
=
The closest standard resistor value is 9.53k. RT(temp)/
RT(25
o
C) is often referred to as the ratio at the given
temp. For this NTC at 50
o
C the ratio is 0.4086.
Step 3: Calculate the Tcold value.
2.86
10k
R3
RT
RT
25
COLD
=
×
=
The ratio for the Curve 2 NTC at 0
o
is 2.816. The differ-
ence represents less than 1/2
o
C (ie actual trip would be
-0.5
o
C instead of 0
o
C.) For temperature trip values other
than 0
o
C and 50
o
C alternate curve-type NTC elements
can be used or an additional resistor can be added to
the Rntc divider to alter the temperture coefficient.
LED Flags
There are two LED drivers on the SC802: CHRGB (Charge)
and CPB (Charger Present). These outputs are open drain
NMOS drivers for controlling LEDs directly. The Table be-
low defines each LED output state.
D
G
A
L
E
L
F
N
O
F
F
O
g
n
n
B
B
P
C
O
C
P
L
V
U
<
C
V
V
O
<
r
w
o
G
t
N
P
d
o
o
X
B
G
R
H
C
>
t
u
o
r
m
<
*
t
m
u
o
r
e
g
h
C
e
P
N
r
t
a
F
C
T
* Output remains on when timer is enabled and t < timeout
The CPB output can be used for a VCC indicator. Re-
gardless of the state of EN, the CPB output reflects the
voltage of the VCC (adapter) input. When VCC is between
the UVLO and OVP thresholds the CPB output is low.
The CHRGB output signifies the charging status. When
the output current is > Itermination, CHRGB=low. CHRGB
is high when Iout is < Itermination. The CHRGB output is
latched during the charge cycle when the output current
is less than Itermination. This latch is reset when the
battery enters a re-charge cycle, or if BIPB, EN, or VCC
are toggled. The CHRGB indicator operates the same
way in both charge and ldo mode.
There are five fault modes detected by the SC802; (In-
put under voltage, input over voltage, NTC temperature,
Max die temperature or OT and pre-charge timeout) The
LED states for these fault modes are shown below.
t
a
F
B
P
C
B
G
R
H
C
O
L
V
U
r
C
C
V
o
C
P
V
O
C
V
f
f
t
a
F
C
T
N
n
o
g
n
n
B
e
g
t
r
u
a
h
C
o
m
i
-
r
P
n
o
g
n
n
B
C
0
5
1
>
j
f
f
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SC802A | Fully Integrated Lithium-Ion Battery Charger System with Timer |
| SC802AIMLTRT | Fully Integrated Lithium-Ion Battery Charger System with Timer |
| SC802EVB | Fully Integrated Lithium-Ion Battery Charger System with Timer |
| SC802IMLTR | Fully Integrated Lithium-Ion Battery Charger System with Timer |
| SC802IMLTRT | Fully Integrated Lithium-Ion Battery Charger System with Timer |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SC802_08 | 制造商:SEMTECH 制造商全稱:Semtech Corporation 功能描述:Fully Integrated Lithium-Ion Battery Charger System with Timer |
| SC802-04 | 制造商:Fuji Electric 功能描述:Diode; 1 A; 0.55 V (Max.) @ 1 A; 40; 40 A; -40 degC; 150 degC; 15 degC/W (Max. |
| SC802-04_01 | 制造商:FUJI 制造商全稱:Fuji Electric 功能描述:SCHOTTKY BARRIER DIODE |
| SC802-04-TE12RA | 制造商:Fuji Electric 功能描述:8022-04-TE12RA |
| SC802-06 | 制造商:Fuji Electric 功能描述:Diode; Surface Mount; 1A IF; 0.58 V (Max.) @ 1 A; 60 V (Peak.); 30A IFRM |
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