NCV3163 ON Semiconductor, NCV3163 Datasheet - Page 11

• Manufacturer Part Number: NCV3163
• Description: Step-Up/Down/Inverting 50-300 kHz Switching Regulator
• Manufacturer: ON Semiconductor

The following Converter Characteristics must be chosen:
NOTES: 1. V
NOTES:
NOTES:
NOTES: 3.
(See Notes 1,2,3)
Calculation
V
V
I pk (Switch)
ripple(pp)
ripple(pp)
I L(avg)
R SC
V out
t on
t off
t on
L
C T
V
2. V
3. The calculated t
I
V
D
out
out
I
in
L
p −
operating input voltage.
−
−
−
−
−
sat
F
Nominal operating input voltage.
Desired output voltage.
Desired output current.
Desired peak−to−peak inductor ripple current. For maximum output current it is suggested that
than 10% of the average inductor current I
threshold set by R
proportionally reduce converter output current capability.
Maximum output switch frequency.
Desired peak−to−peak output ripple voltage. For best performance the ripple voltage should be kept to a low value
since it will directly affect line and load regulation. Capacitor C
electrolytic designed for switching regulator applications.
− Output rectifier forward voltage drop. Typical value for 1N5822 Schottky barrier rectifier is 0.5 V.
− Saturation voltage of the output switch, refer to Figures 10 and 11.
32.143 · 10 *6
DI L
f
V
V
in
on
in
ƒ
V
/t
8
I L(avg) )
* V sat * V out
off
ref
Step−Down
* V sat * V out
V out ) V F
I pk (Switch)
ƒ
SC
1
t on
t
must not exceed the minimum guaranteed oscillator charge to discharge ratio of 8, at the minimum
* 20 @ 10 *12
C O
off
DI L
. If the design goal is to use a minimum inductance value, let
t on
t off
0.25
R 2
R 1
I out
) 1
2
) 1
) (ESR) 2
DI L
2
Figure 22. Design Equations
t on
NCP3163, NCV3163
http://onsemi.com
L(avg)
32.143 · 10 *6
. This will help prevent I
f
11
V out ) V F – V in
V
I out
V
I L(avg) )
ƒ
ref
in
V
[
I pk (Switch)
Step−Up
in
* 20 @ 10 *12
t on
t
* V sat
DI L
off
t on I out
t on
t
R 2
R 1
– V sat
0.25
off
t on
t off
O
C
) 1
O
should be a low equivalent series resistance (ESR)
) 1
) 1
DI L
2
t on
pk (Switch)
from reaching the current limit
D
32.143 · 10 *6
I
L
= 2(I
f
L(avg)
Voltage−Inverting
I out
V
V
D
I L(avg) )
ƒ
ref
I
). This will
in
|V out | ) V F
L
V
[
I pk (Switch)
be chosen to be less
in
* 20 @ 10 *12
* V sat
DI L
t on
t
off
t on
t
t on I out
R 2
R 1
off
0.25
* V sat
t on
t off
C
) 1
O
) 1
) 1
DI L
2
t on