20
LT1776
PART NUMBER DESCRIPTION COMMENTS
LT1076 2A, 100kHz Step-Down Switching Regulator Operation Up to 45V Input (64V for HV Version)
LTC
®
1149 High Efficiency Synchronous Step-Down Switching Regulator Operation Up to 48V Input, 95% Efficiency, 100% Duty Cycle
LT1374 4.5A, 500kHz Step-Down Switching Regulator Converts 12V to 3.3V at 2.5A in SO-8 Package
LT1375/LT1376 1.5A, 500kHz Step-Down Switching Regulators Operation Up to 25V Input, Synchronizable (LT1375)
LT1620 Rail-to-Rail Current Sense Amplifier Transforms Switching Regulators into High Efficiency
Battery Chargers
LT1676 Wide Input Range, High Efficiency, Step-Down Switching Regulator 7.4V to 60V Input, 100kHz Operation, 700mA Internal Switch
LT1777 Low Noise Buck Regulator Operation up to 48V, Controlled Voltage and Current
Slew Rates
LINEAR TECHNOLOGY CORPORATION 1998
sn1776 1776fs LT/TP 0499 4K • PRINTED IN
USA
Wide V
IN
Range, High Efficiency Battery Charger
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear-tech.com
LOAD CURRENT (mA)
20
50
40
30
90
80
70
60
1776 TA03
EFFICIENCY (%)
10
1000
100
V
IN
= 12V
V
IN
= 24V
Battery Charger Efficiency—
Constant V
OUT
Region
OUTPUT CURRENT (mA)
0
1
0
OUTPUT VOLTAGE (V)
2
3
4
5
7
6
50 100 150 250200
1776 TA05
OUTPUT VOLTAGE (V)
0
60
70
80
35
1776 TA04
50
40
12
46
30
20
EFFICIENCY (%)
90
V
IN
= 12V
V
IN
= 24V
Battery Charger Efficiency—
Constant I
OUT
Region
Battery Charger Output Voltage
vs Output Current
V
IN
V
CC
V
SW
U1
LT1776
U3
LT1121-5
FB
V
C
SHDN
SYNC
C1: PANASONIC HFQ
C2: AVX TPSD107M010R0080
L1: COILCRAFT DO3316P-104
7
C1
39µF
63V
5
4
1776 TA02
2
3
8
1
V
IN
10V TO 30V
(SEE TEXT)
6
GND
V
CC
IN
+
PROG
U2
LT1620
I
OUT
IN
–
NC
AVG
SENSE
2
5
4
6
3
8
1
7
GND
+
D1
MBRS1100
R1
46.4k
1%
BATTERY
R2
12.1k
1%
R3
22k
R5
3k
R6
12k
L1
100µH
R4
0.5Ω
C4
2200pF
C3
100pF
C7
0.1µF
C5
100pF
C6
0.33µF
C2
100µF
10V
C8
1µF
+
+
TYPICAL APPLICATION
U
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