TL497A
SWITCHING VOLTAGE REGULATORS
SLVS009D – JUNE 1976 – REVISED JULY 1999
APPLICATION INFORMATION
R
L
CL
V
O
V
I
DESIGN EQUATIONS
V
O
14 13
10
8
R1
I
2 I max
(PK)
O
V
I
TL497A
4
C
O
V
I
L ( H)
t
( s)
on
I
(PK)
1
2
3
5
6
7
R2 = 1.2 kΩ
Choose L (50 to 500 µH), calculate
(25 to 150 µs)
C
T
t
on
C (pF)
T
12 t
( s)
on
BASIC CONFIGURATION
(Peak Switching Current = I
< 500 mA)
(PK)
R
L
CL
13
R1
(V – 1.2 V) k
O
V
I
V
O
0.5 V
R
CL
I
(PK)
V
I
R1
14
10
8
I
I
(PK)
O
V
O
V
C
( F)
t
( s)
on
C
O
O
TL497A
(PK)
ripple
1
2
3
4
5
R2 = 1.2 kΩ
C
T
EXTENDED POWER CONFIGURATION
(using external transistor)
Figure 1. Positive Regulator, Step-Up Configurations
5
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TI [ TEXAS INSTRUMENTS ]
