LT1072CTPBF LINEAR TECH, LT1072CTPBF Datasheet - Page 10

• Manufacturer Part Number: LT1072CTPBF
• Manufacturer: LINEAR TECH

LT1072
TYPICAL APPLICATIO S
10
OPTIONAL
FILTER
INPUT
–12V
V
L3
25µF*
IN
C4
20 TO 30V
25µF*
+
Negative to Positive Buck-Boost Converter
C4
V
IN
+
GND
GND
LT1072
0.15µF
V
IN
**
C2
LT1072
0.22µF
*
V
REQUIRED IF INPUT LEADS ≥ 2"
OPTIONAL TO REPLACE R4 AND C3
IN
V
C1
C
V
R3
1.5k
SW
**
FB
V
220µH
C
L1**
V
R3
2.2k
SW
FB
R4
1k
U
R2
1.24k
D2
1000µF
C3
0.47µF
**
D1
*
C2
REQUIRED IF INPUT LEADS ≥ 2"
PULSE ENGINEERING 52626
OPTIONAL
OUTPUT
FILTER
+
1
L2
N*
N* =
Q1
R1
11.3k
D1
1
3
C3
Flyback Converter
V
12V, 0.5A
OUT
OPTIONAL
+
LT1072 • TA05
FILTER
10µH
200µF
L2
C1
500µF
C4
R1
3.74k
R2
1.24k
V
5V
1.5A
OUT
V
+
–
0V
0V
IN
0
0
0
0
V
IN
Q1
V
a
SNUB
I
c
∆I
PRI
t =
C1
1000pF
b
d
(I
R1
R
1k
PRI
V
S
SNUB
V
I
I
) (L
PRI
PRI
OUT
CLAMP TURN-ON
GND
L
+ V
)
External Current Limit
N • V
LT1072
SPIKE
f
I
PRI
V
N
IN
IN
PRIMARY FLYBACK VOLTAGE =
LT1072 SWITCH VOLTAGE
AREA “a” = AREA “b” TO MAINTAIN
ZERO DC VOLTS ACROSS PRIMARY
SECONDARY VOLTAGE
AREA “c” = AREA “d” TO MAINTAIN
ZERO DC VOLTS ACROSS SECONDARY
PRIMARY CURRENT
SECONDARY CURRENT
LT1070 SWITCH CURRENT
SNUBBER DIODE CURRENT
V
C
V
R2
SW
FB
C2
NOTE THAT THE LT1072 GND PIN
IS NO LONGER COMMON TO V
V
LT1072 • TA06
OUT
LT1072 • TA04
N
+ V
IN
f
(–)
1072fc