LT1513_15 Datasheet, PDF (1/16 Pages) Linear Technology – SEPIC Constant- or Programmable-Current/ Constant-Voltage Battery Charger

LT1513/LT1513-2
SEPIC Constant- or
Programmable-Current/
Constant-Voltage Battery Charger
FEATURES
s _{Charger Input Voltage May Be Higher, Equal to or}
Lower Than Battery Voltage
s _{Charges Any Number of Cells Up to 20V}
s _{1% Voltage Accuracy for Rechargeable Lithium}
Batteries
s _{100mV Current Sense Voltage for High Efficiency}
(LT1513)
s _{0mV Current Sense Voltage for Easy Current}
Programming (LT1513-2)
s _{Battery Can Be Directly Grounded}
s _{500kHz Switching Frequency Minimizes}
Inductor Size
s _{Charging Current Easily Programmable or Shut Down}
U
APPLICATIONS
s _{Charging of NiCd, NiMH, Lead-Acid or Lithium}
Rechargeable Cells
s _{Precision Current Limited Power Supply}
s _{Constant-Voltage/Constant-Current Supply}
s _{Transducer Excitation}
s _{Universal Input CCFL Driver}
DESCRIPTION
The LT^®1513 is a 500kHz current mode switching regula-
tor specially configured to create a constant- or program-
mable-current/constant-voltage battery charger. In addition
to the usual voltage feedback node, it has a current sense
feedback circuit for accurately controlling output current
of a flyback or SEPIC (Single-Ended Primary Inductance
Converter) topology charger. These topologies allow the
current sense circuit to be ground referred and completely
separated from the battery itself, simplifying battery switch-
ing and system grounding problems. In addition, these
topologies allow charging even when the input voltage is
lower than the battery voltage. The LT1513 can also drive
a CCFL Royer converter with high efficiency in floating or
grounded mode.
Maximum switch current on the LT1513 is 3A. This allows
battery charging currents up to 2A for a single lithium-ion
cell. Accuracy of 1% in constant-voltage mode is perfect
for lithium battery applications. Charging current can be
easily programmed for all battery types.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
WALL
ADAPTER
INPUT + ^C3
22µF
25V
• ^L1A*
C2**
7
4.7µF
D1^†
V_IN
V_SW ⁵
CHARGE
SYNC
AND/OR
SHUTDOWN SHUTDOWN
LT1513
6
S/S
GND
V_C
4 TAB 1
2
V_FB
I_FB
R4
3 39Ω
R5
270Ω
C5
0.1µF
C4
0.22µF
L1B*
R1
•
R2
R3
0.08Ω
1.25A
+ ^C1
22µF
25V
×2
* L1A, L1B ARE TWO 10µH WINDINGS ON A
LT1513 • TA01
COMMON CORE: COILTRONICS CTX10-4
** CERAMIC MARCON THCR40EIE475Z OR TOKIN 1E475ZY5U-C304
† _{MBRD340 OR MBRS340T3. MBRD340 HAS 5µA TYPICAL}
LEAKAGE, MBRS340T3 50µA TYPICAL
Figure 1. SEPIC Charger with 1.25A Output Current
Maximum Charging Current
2.4
2.2
SINGLE Li-Ion CELL
2.0
(4.1V)
1.8
DOUBLE Li-Ion
1.6
CELL (8.2V)
1.4
12V
1.2
16V
1.0
20V
0.8
0.6
0.4
0
BATTERY
VOLTAGE
5 10 15 20 25 30
INPUT VOLTAGE (V)
INDUCTOR = 10µH
ACTUAL PROGRAMMED CHARGING CURRENT WILL BE
INDEPENDENT OF INPUT VOLTAGE IF IT DOES NOT
EXCEED VALUES SHOWN
LT1513 • TA02
sn1513 1513fas
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