ncv33063a ON Semiconductor, ncv33063a Datasheet - Page 10

• Manufacturer Part Number: ncv33063a
• Description: 1.5 A, Stepup/down/ Inverting Switching Regulators
• Manufacturer: ON Semiconductor

V
V
The following power supply characteristics must be chosen:
V
V
I
f
V
NOTE: For further information refer to Application Note AN920A/D and AN954/D.
out
min
Calculation
sat
F
in
out
ripple(pp)
(t
I
= Forward voltage drop of the output rectifier.
pk(switch)
− Nominal input voltage.
− Desired output current.
on
− Minimum desired output switching frequency at the selected values of V
t
L
− Desired output voltage,
= Saturation voltage of the output switch.
on
R
C
C
(min)
t
t
off
on
+ t
/t
sc
O
T
off
off
− Desired peak−to−peak output ripple voltage. In practice, the calculated capacitor value will need to be increased due to its
)
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.
(V in(min) * V sat )
V out ) V F * V in(min)
2I
out(max)
I
V in(min) * V sat
pk(switch)
(t
4.0 x 10
9
0.3/I
on
t on ) t
|V
Step−Up
V ripple(pp)
t on
t
off
+ t
out
I out t on
pk(switch)
off
1
f
) 1
| + 1.25 1 ) R2
t on
t
) − t
−5
off
off
t
on
MC34063A, MC33063A, NCV33063A
off
) 1
t
on(max)
Figure 15. Design Formula Table
R1
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(V in(min) * V sat * V out )
V
in(min)
I pk(switch) (t on ) t off )
I
10
pk(switch)
(t
4.0 x 10
0.3/I
Step−Down
on
8V
V out ) V F
t on ) t
2I out(max)
t on
t
off
+ t
* V sat * V out
ripple(pp)
pk(switch)
1
off
f
) 1
) − t
−5
in
off
and I
t
on
off
O
.
t
on(max)
(V in(min) * V sat )
2I
I
out(max)
pk(switch)
Voltage−Inverting
(t
4.0 x 10
9
|V out | ) V F
0.3/I
V
on
t on ) t
in
V ripple(pp)
t on
t
off
+ t
I out t on
pk(switch)
* V sat
1
off
f
) 1
t on
t
) − t
−5
off
off
t
on
off
) 1
t
on(max)