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