TL497A
SWITCHING VOLTAGE REGULATORS
SLVS009D – JUNE 1976 – REVISED JULY 1999
APPLICATION INFORMATION
Switching
Circuit
V
I
V
O
3-Term
Reg < 12 V
Control
14
13
TL497A
5
EXTENDED INPUT CONFIGURATION WITHOUT CURRENT LIMIT
R
CL
Switching
Circuit
V
I
V
O
DESIGN EQUATIONS
Q1
V
BE(Q1)
V
reg
10 mA
R
3-Term
Reg < 12 V
CL
I
limit (PK)
1 kΩ
V
I
R1
I
B(Q2)
Control
R2
14
13
R2
V
1 10 k
reg
TL497A
R1
5
Q2
CURRENT LIMIT FOR EXTENDED INPUT CONFIGURATION
Figure 4. Extended Input Voltage Range (V > 12 V)
I
8
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265