Datasheet
C
R 2.74M 2.74M 3.01M 8.49M= W + W + W = W
REF
V 6 V=
REF C
D
OUT REF
V R
6 V 8.49M
R 132.7k
V V 390 V 6 V
´
´ W
= = = W
- -
D
R 133k= W
C D
OVP
D
R R
8.49M 133k
V 6.48 V 6.48 V 420.1V
R 133k
+
W + W
= = =
W
m
g 50 S= m
REF
OUT
V
6 V
H 0.015
V 390 V
= = »
Z
RIPPLE m
100mV 100mV
R 9.52 k
V H g 14 V 0.015 50 S
= = = W
´ ´ ´ ´ m
Z
LINE
Z
1 1
C 1.78 F
f 47Hz
2 9.52k
2 R
5
5
= = = m
p´ ´ W
p´ ´
p
MIN
Z
1 1
C 770pF
f 45kHz
2 9.52k
2 R
2
2
= = =
p´ ´ W
p´ ´
Z
R 9.53k= W
Z
C 2.2 F= m
P
C 820pF=
UCC28063
SLUSAO7 – SEPTEMBER 2011
www.ti.com
Programming V
OUT
Resistor R
C
is selected to minimize loading on the power line when the PFC is disabled. Construct resistor R
C
from two or more resistors in series to meet high-voltage requirements. Resistor R
D
is then calculated based on
R
C
, the reference voltage, V
REF
, and the required output voltage, V
OUT
. Based on the values shown in
Equation 51 to Equation 54, the primary output over-voltage protection threshold should be as shown in
Equation 55:
(51)
(52)
(53)
Select a standard value for R
D
.
(54)
(55)
Voltage Loop Compensation
Resistor R
Z
is sized to attenuate low-frequency ripple to less than 2% of the voltage amplifier output range. This
value ensures good power factor and low harmonic distortion on the input current.
The transconductance amplifier small-signal gain is shown in Equation 56:
(56)
The voltage-divider feedback gain is shown in Equation 57:
(57)
The value of R
Z
is calculated as shown in Equation 58:
(58)
C
Z
is then set to add 45° phase margin at 1/5th of the line frequency, as shown in Equation 59:
(59)
C
P
is sized to attenuate high-frequency switching noise, as shown in Equation 60:
(60)
Standard values should be chosen for R
Z
, C
Z
and C
P
, as shown in Equation 61 to Equation 63.
(61)
(62)
(63)
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