Diodes AZ34063A - Manual (Page 9)

1.5A STEP-DOWN/STEP-UP/INVERTING DC-DC CONVERTER AZ34063A
Data Sheet
9
Jan. 2013 Rev. 1. 6 BCD Semiconductor Manufacturing Limited
Figure 12. Step-Down converter (Note 6)
Typical Applications (Continued)
+
-
Ipk
B
1.25V
Reference
Regulator
A
1
S
R
Q
I
PK
C
T OSC
V
IN
25V
C1
100 μF
Rsc
0.33
L2 1.0 μH
C3
100 μF
Optional
Filter
5V/500mA
V
OUT
D1
1N5819
L1
220 μH
C
T
470 pF
+
+ R1 3.6k
R2
1.2k
C2
470 μF
+
U1 AZ34063A
2
3
4 5
6
7
8
V
OUT
Note 6: This is a typical step-down converter configuration. The working process in the steady state is similar to
step-up converter, V
PIN5
=V
OUT
*R2/(R1+R2)=1.25 (V), the output voltage can be decided by V
OUT
=1.25*
(R1+R2)/R2 (V).