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