TL497A Datasheet, PDF (8/9 Pages) Texas Instruments – SWITCHING VOLTAGE REGULATORS

TL497A
SWITCHING VOLTAGE REGULATORS
SLVS009D – JUNE 1976 – REVISED JULY 1999
APPLICATION INFORMATION
VI
Switching
Circuit
VO
3-Term
Reg < 12 V
14
13
Control
TL497A
5
EXTENDED INPUT CONFIGURATION WITHOUT CURRENT LIMIT
RCL
VI
Q1
3-Term
Reg < 12 V
Vreg
1 kΩ
R2
R1
Q2
10 mA
Switching
Circuit
14 13
Control
TL497A
5
VO
DESIGN EQUATIONS
+ RCL
VBE(Q1)
Ilimit _(PK)
) R1
VI
IB(Q2)
ǒ Ǔ _{+ * R2}
W Vreg 1 10 k
CURRENT LIMIT FOR EXTENDED INPUT CONFIGURATION
Figure 4. Extended Input Voltage Range (V_I > 12 V)
8
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