AP34063 Diodes, Inc., AP34063 Datasheet - Page 8

• Manufacturer Part Number: AP34063
• Description: Universal Dc/dc Converter
• Manufacturer: Diodes, Inc.

Design Formula Table
V
V
The following power supply characteristics must be chosen:
V
V
I
f
V
AP34063 Rev. 3
out
min
sat
F
in
out
ripple(pp)
= Forward voltage drop of the output rectifier.
- Nominal input voltage.
- Desired output current.
- Minimum desired output switching frequency at the selected values of V
= Saturation voltage of the output switch.
- Desired output voltage, |V
- Desired peak-to-peak output ripple voltage. In practice, the calculated capacitor value will need to be increased due to its
Calculation
I
( t
pk
equivalent series resistance and board layout. The ripple voltage should be kept to a low value since it will directly affect the
line and load regulation.
t
on
L
on
(switch)
R
C
C
t
t
(min)
+ t
off
on
/ t
sc
O
T
off
off
)
out
| = 1.25 (1+R2/R1)
2I
( V
9
V
out (max)
in (min)
out
( t
0.3 / I
I
4.0×10 -5 t
V
pk (switch)
t
t
V
on
Step-Up
on
off
+ V
in (min)
I
t
ripple (pp)
on
out
+t
– V
1/f
(t
+ t
pk (switch)
F
off
t
on
on
-V
- V
) - t
off
sat
/ t
+1
in (min)
on
off
sat
)
off
+1)
t
on (max)
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I
( V
pk (switch)
v
in(min)
( t
in (min)
0.3 / I
I
Step-Down
pk (switch)
4.0×10 -5 t
8V
t
t
-V
in
on
on
off
2I
v
t
and I
out
on
out
ripple (pp)
+t
out (max)
- v
( t
1/f
– V
+ t
pk (switch)
off
)
UNIVERSAL DC/DC CONVERTER
+ v
off
o
sat
.
) - t
off
sat
+ t
F
+1
- v
on
off
on
out
)
(max)
t
on
9
( V
2I
Voltage-Inverting
out (max)
in (min)
( t
V
0.3 / I
I
pk (switch)
4.0×10 -5 t
I
t
t
ripple (pp)
on
Iv
out
on
off
AP34063
t
V
out
©
on
+ t
t
– V
in
on
1/f
(t
Diodes Incorporated
+ t
pk (switch)
l + v
off
- v
on
sat
off
) - t
JULY 2007
+1
/ t
sat
F
on
off
)
off
t
+1)
on (max)