E-L5970D Datasheet, PDF (11/16 Pages) STMicroelectronics – Up to 1A step down switching regulator

L5970D
6
Application ideas
Application ideas
Figure 18. Dual output voltage with auxiliary winding
D2
N1/N2=2 ^1N4148
VOUT1=5V
30mA
VIN=12V
C1
10uF
25V
Ceramic
VCC
8
C2
220pF
COMP
4
U1
L5970D
C3
22nF
2 67
SYNC VREF GND
R3
4.7k
3.3V
OUT
1
FB
5
3
INH
Lp=22uH
D1
STPS25L25U
C4
100uF
10V
VOUT=3.3V
0.5A
C5
47uF
10V
Figure 19. Buck-boost regulator
VIN=12V
VCC
8
U1
C1
10uF
25V
Ceramic
C2
10uF
35V
C3
Ceramic 220pF
COMP
4
L5970
2 67
C4
22nF
SYNC VREF GND
R3
4.7k
3.3V
OUT
1
5 ^FB
3
INH
2.7k
24k
L1
33uH
D1
STPS2L25U
C5
100uF
16V
VOUT=-12V/0.3A
Vin=12V Vout=-12V Iout=0.5A Efficiency=81%
Figure 20. Positive Buck-Boost regulator
VIN=5V
C1
10uF
25V
Ceramic
C2
220pF
VCC
8
U1
COMP
L5970
4
2 67
C3
22nF
R3
4.7k
SYNC VREF GND
3.3V
OUT
1
5 ^FB
3
D1
STPS2L25U
INH
L1
33uH
D2
STPS2L25U
VOUT=12V/0.3A
24k
M1
STN4NE03L
C4
100uF
16V
2.7k
Vin=5V Vout=12V Iout=0.3A Efficiency=76%
Figure 21. Synchronization example
VIN
VCC
8
OUT
1
VCC
8
OUT
1
COMP
4
2
L5970D
67
SYNC VREF GND
FB
5
3
INH
COMP
4
2
L5970D
67
SYNC VREF GND
FB
5
3
INH
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