TL497A Datasheet, PDF (7/9 Pages) Texas Instruments – SWITCHING VOLTAGE REGULATORS

TL497A
SWITCHING VOLTAGE REGULATORS
APPLICATION INFORMATION
SLVS009D – JUNE 1976 – REVISED JULY 1999
RCL
L
VI
14 13
10
8
†
R1
TL497A
CO
1 2 3 45
R2 = 1.2 kΩ
ƪ ^{Ť Ť}ƫ ^{DESIGN EQUATIONS}
+ ) I(PK)
2 IO max 1
VO
VI
+ L (mH)
m ^VI
I(PK)
ton(
s)
VO
CT
BASIC CONFIGURATION
(Peak Switching Current = I(PK) < 500 mA)
RCL
L
VI
14 13
10
8
†
R1
Choose L (50 to 500 µH), calculate
ton (10 to 150 µs)
[ m CT(pF) 12 ton( s)
ǒŤ Ť Ǔ _{+ R1}
W VO – 1.2 V k
+ RCL
0.5 V
I(PK)
ƪ_{Ť Ť} ƫ _{[ CO (mF) ton(ms)}
) ^VI
VO
I(PK)
IO
Vripple (PK)
TL497A
1 2 3 45
CO
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