TL497A
SWITCHING VOLTAGE REGULATORS
SLVS009D – JUNE 1976 – REVISED JULY 1999
APPLICATION INFORMATION
R
L
CL
V
I
V
O
DESIGN EQUATIONS
14
13
10
8
7
R1
I
2 I max
O
(PK)
TL497A
C
O
V
– V
I
I
O
L ( H)
t
( s)
on
(PK)
1
2
3
4
5
6
R2 = 1.2 kΩ
Choose L (50 to 500 µH), calculate
(10 to 150 µs)
C
t
T
on
C (pF)
T
12 t ( s)
on
BASIC CONFIGURATION
(Peak Switching Current = I < 500 mA)
(PK)
R1
(V – 1.2 V) k
O
R
L
CL
0.5 V
V
O
R
V
I
CL
I
(PK)
V
V
I
O
I
I
(PK)
(PK)
O
V
O
C
( F)
t
( s)
on
O
V
ripple
14
13
10
8
7
R1
TL497A
4
C
O
R2 = 1.2 kΩ
1
2
3
5
6
C
T
EXTENDED POWER CONFIGURATION
(using external transistor)
Figure 2. Positive Regulator, Step-Down Configurations
6
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TI [ TEXAS INSTRUMENTS ]
