TL497A
SWITCHING VOLTAGE REGULATORS
SLVS009D – JUNE 1976 – REVISED JULY 1999
APPLICATION INFORMATION
RCL
VI
L
DESIGN EQUATIONS
14 13
TL497A
1
2
3
4
10
8
†
R1
CO
I
+
2 IO max 1
)
(PK)
m
V
O
V
I
5
R2 = 1.2 kΩ
VO
L ( H)
+
I VI
(PK)
t on( s)
m
CT
Choose L (50 to 500
µH),
calculate
ton (10 to 150
µs)
C (pF)
T
[
12 ton(
m
s)
k
BASIC CONFIGURATION
(Peak Switching Current = I(PK) < 500 mA)
RCL
VI
L
+
VO – 1.2 V
R
+
0.5 V
CL
I
R1
(PK)
C
O
( F)
W
I
V
V
I
(PK)
)
IO
14
13
TL497A
10
8
R1
†
CO
m
[
ton(
m
s)
O
V
ripple
(PK)
1
2
3
4
5
R2 = 1.2 kΩ
VO
CT
EXTENDED POWER CONFIGURATION
(using external transistor)
† Use external catch diode, e.g., 1N4001, when building an inverting supply with the TL497A.
Figure 3. Inverting Applications
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
7
TI [ TEXAS INSTRUMENTS ]
