ncp1608d ON Semiconductor, ncp1608d Datasheet - Page 22

• Manufacturer Part Number: ncp1608d
• Description: Critical Conduction Mode Pfc Controller Utilizing Ota
• Manufacturer: ON Semiconductor

BOOST DESIGN EQUATIONS
rms Input Current
Maximum Inductor Peak
Current
Inductor Value
Maximum On Time
Off Time
Switching Frequency
On Time Capacitor
Inductor Turns to ZCD
Turns Ratio
Resistor from ZCD
winding to the ZCD pin
Output Voltage and Output
Divider
Maximum Output Voltage
for OVP Detection and
Recovery
Output Capacitor
Output Capacitor rms
Current
V
V
out(OVPL)
out(OVP)
I
C(RMS)
Components are identified in Figure 1
V
f
C
SW
out
bulk
+
+
+
+
+ V
N
w
R
R
L v
V
V
2 @ L @ P
R
V
B
V
out1
out2
Vac
OVP
OVP
REF
REF
2 @ p @ V
Ct w
ZCD
I
REF
: N
L(peak),MAX
t
off
9 @ p @ Vac
t
Vac
+
+
on(MAX)
ZCD
@ V
@ V
2 @ V
2
@ R
w
+
@ h
h @ Vac
I
R
REF
2 @ P
bias(out)
2
out
Iac +
I
REF
Vac@ sin q @ 2
v
V
FB
2 @ 32 @ P
ZCD(MAX)
@
ripple(peak−peak)
http://onsemi.com
out
out
out1
@ 1 *
−V
@
V
+
@ R
V
out
+
@ P
out
OVP(HYS)
V
out
LL
LL
@
2
V
2 @ L @ P
R
h @ Vac
h @ Vac
out
V
2 @ Vac
@ L @ I
*
REF
R
P
V
P
out
t
2
out1
out
R
@ V
2 @ 2 @ P
* Vac @ h
h @ Vac
on
out1
out2
out
@ V
ZCD(ARM)
@ (N
out
out2
22
out
Vac @ | sin q | @ 2
@ f
* 1 * R
out
@ R
2 @ Vac
Ct(MAX)
@
2
charge
) R
SW(MIN)
@ R
@ R
B
LL
* 1
HL
R
@ h
out
R
FB
: N
@ f
LL
2
out2
V
out2
out
out1
FB
2
FB
line
out
ZCD
* I
HL
) R
) 1
@
@ R
@ V
out1
R
)
R
load(RMS)
out2
out2
FB
FB
out
) R
@ R
) 1
FB
FB
2
) 1
h (the efficiency of only the PFC
stage) is generally in the range of 90
− 95%. Vac is the rms ac line input
voltage.
Where Vac
put voltage. I
minimum line input voltage.
f
switching frequency. The maximum L
is calculated at both the minimum
line input voltage and maximum line
input voltage.
The maximum on time occurs at the
minimum line input voltage and max-
imum output power.
The off time is a maximum at the
peak of the ac line voltage and ap-
proaches zero at the ac line zero
crossings. Theta (q) represents the
angle of the ac line voltage.
I
specification table.
Where Vac
input voltage. V
the specification table. The maximum
value of V
calculation.
Where I
current for the ZCD pin (10 mA)
Where V
voltage and R
istor used for FPP. V
shown in the specification table.
I
put voltage divider.
V
shown in the specification table.
Where f
and V
peak output ripple voltage. Use f
47 Hz for universal input worst case.
The ripple voltage must not exceed
the OVP voltage for V
Where I
rent.
SW(MIN)
charge
bias(out)
OVP
/V
ripple(peak−peak)
and V
REF
ZCD(MAX)
line
load(RMS)
is the bias current of the out-
is the minimum desired
REF
ZCD(ARM)
LL
HL
is the ac line frequency
and V
L(peak),MAX
Ct(MAX)
is the internal reference
is the minimum line in-
FB
is the maximum line
ZCD(ARM)
is the pull down res-
is maximum rated
is the rms load cur-
OVP(HYS)
is used for this
are shown in the
REF
is the peak−to−
out
occurs at
.
and R
is shown in
are
FB
line
are
=