mp6001dn MPS, mp6001dn Datasheet - Page 11

• Manufacturer Part Number: mp6001dn
• Description: Monolithic Flyback/forward Dc-dc Converter
• Manufacturer: MPS

RCD Type of Snubber Design Procedure:
1. Setting V
Higher V
power switch, but lower power loss. Usually, V
can be set as 20%~40% of (V
2. Estimated RCD snubber loss is given by:
Where:
P
inductance (L
at the power switch turn-off.
3. Calculate values of the R
snubber by:
Input Capacitor
The input capacitors (C1) are chosen based
upon the AC voltage ripple on the input
capacitors, RMS current ratings, and voltage
rating of the input capacitors.
MP6001 Rev. 0.91
9/21/2007
LK
Figure 6—Voltage Waveform of Primary
Power Switch Shown in Figure 5(C)
V
is the energy stored in the leakage
DS
P
P
means higher voltage stress on the
RCD
P
TM
LK
P
_
LK
LOSS
), which carries the peak current
R =
R
D
=
D
V
1
2
=
×
C
P
L
C
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
P
RCD
LK
LK
D
V
V
>>
×
×
P
P
_
1 (
I
2
LOSS
P
N x V
f
+
2
1
S
D
IN
×
N
+ NxV
MP6001 – MONOLITHIC FLYBACK/FORWARD DC-DC CONVERTER
and C
f
O
×
V
C
P
V
MP6001_F06
O
)
O
D
).
© 2007 MPS. All Rights Reserved.
V
0
of RCD
IN
www.MonolithicPower.com
P
For a given AC ripple voltage, ΔV
be derived from:
ΔV
converter stability. C1 RMS current has to be
considered:
C1 has to have enough RMS current rating.
Output Filter
The simplest filter is an output capacitor (C2),
whose capacitance is determined by the output
ripple requirement.
The current waveform in the output capacitor is
mostly in rectangular shape. The full load
current is drawn from the capacitors during the
primary switch on time. The worse case for the
output ripple occurs under low line and full load
conditions. The ripple voltage can be estimated
by:
ESR also needs to be specified for the output
capacitors. This is due to the step change in D2
current results in a ripple voltage that is
proportional to the ESR. Assuming that the D2
current waveform is in rectangular shape, the
ESR requirement is then obtained by given the
output ripple voltage.
The total ripple voltage can be estimated by:
IN_PP
may affect the C1 voltage rating and
Δ
V
O
−
Δ
Δ
PP
I
V
V
RMS
C
O
0
1
=
−
−
PP
PP
=
_
Δ
C
V
I
−
_
IN
1
C
R
O
=
ESR
−
×
=
PP
Δ
I
IN
1 (
V
I
−
O
×
IN
−
=
C
×
D
_
I
+
O
PP
1 (
)
C
1 (
Δ
×
×
2
−
D
V
−
T
D
ESR
×
O
D
D
S
−
)
f
)
PP
S
IN_PP
_
ESR
, C1 can
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