TL497A Datasheet, PDF (6/9 Pages) Texas Instruments – SWITCHING VOLTAGE REGULATORS

TL497A
SWITCHING VOLTAGE REGULATORS
SLVS009D – JUNE 1976 – REVISED JULY 1999
APPLICATION INFORMATION
RCL
VI
14
13
10
8
TL497A
1
23 4 567
CT
L
R1
R2 = 1.2 kΩ
VO
DESIGN EQUATIONS
+ I(PK) 2 IO max
CO
+ L (mH)
m VI – VO
I(PK)
ton(
s)
Choose L (50 to 500 µH), calculate
ton (10 to 150 µs)
BASIC CONFIGURATION
(Peak Switching Current = I(PK) < 500 mA)
RCL
L
VI
14
13
10
8
R1
[ m CT(pF) 12 ton( s)
+ W R1 (VO – 1.2 V) k
VO
+ RCL
0.5 V
I(PK)
[ ^{ƪ ) ƫ} CO (mF) ton(ms)
VI * VO
VO
I(PK)
Vripple (PK)
IO
TL497A
12
3 4 5 67
CT
CO
R2 = 1.2 kΩ
EXTENDED POWER CONFIGURATION
(using external transistor)
Figure 2. Positive Regulator, Step-Down Configurations
6
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