PFS704 POWERINT [Power Integrations, Inc.], PFS704 Datasheet - Page 10

• Manufacturer Part Number: PFS704
• Description: High Power PFC Controller with Integrated High-Voltage MOSFET
• Manufacturer: POWERINT [Power Integrations, Inc.]

Application Example
A High Efficiency, 347 W, 380 VDC Universal Input PFC
The circuit shown in Figure 11 is designed using a PFS714EG
device from the HiperPFS family of integrated PFC controllers.
This design is rated for a continuous output power of 347 W
and provides a regulated output voltage of 380 VDC nominal
maintaining a high input power factor and overall efficiency from
light load to full load.
Fuse F1 provides protection to the circuit and isolates it from the
AC supply in case of a fault. Diode bridge BR1 rectifies the AC
input. Capacitors C3, C4, C5, C6 and C19 together with
inductors L1, L2, L3 and L4 form the EMI filter reducing the
common mode and differential mode noise. Resistors R1, R3
and CAPZero, IC U2 are required to discharge the EMI filter
capacitors once the circuit is disconnected. CAPZero
eliminates static losses in R1 and R2 by only connecting these
components across the input when AC is removed.
The boost converter stage consists of inductor L5, diode rectifier
D2 and the HiperPFS IC U1. This converter stage works as a
boost converter and controls the input current of the power
supply while simultaneously regulating the output DC voltage.
Diode D1 prevents a resonant build up of output voltage at start-
up by bypassing inductor L5 while simultaneously charging
output capacitor C15. Thermistor RT1 limits the inrush input
current of the circuit at start-up and prevents saturation of L5.
In most high-performance designs, a relay will be used to
bypass the thermistor after start-up to improve power supply
efficiency. Therefore efficiency measurement, that represents
Figure 11. 347 W PFC using PFS714EG.
Rev. D 12/11
CAP006DG
CAPZero
N
L
E
U2
10
6.3 A
F1
220 kΩ
220 kΩ
R1
R2
PFS704-729EG
D1
D2
275 VAC
320 VAC
*Optional Component
10 Ω
680 nF
R18
2 W
RV1
C3
Ferrite Bead
L4
14 mH
L1
Auxiliary
Supply
Power
+
100 Ω
100 Ω
R16
R6
310 V
1 µF
C19
47 µF
50 V
C8
250 VAC
250 VAC
680 pF
680 pF
100 µH
C5
C4
L2
3.01 kΩ
100 µH
DL4001
R17
1%
L3
D5
275 VAC
100 nF
10 Ω
RT1
MMBT4401LT1G
C6
t
GBU806
O
600 V
BR1
Q3
100 nF
50 V
C20
400 V
1 µF
C7
1.5 MΩ
1.5 MΩ
1 MΩ
R19
100 nF
the high performance configuration, the thermistors should be
shorted. Capacitors C14 and C21 are used for reducing the
loop length and area of the output circuit to reduce EMI and
overshoot of voltage across the drain and source of the
MOSFET inside U1 at each switching instant.
The PFS714EG IC requires a regulated supply of 12 V for
operation and must not exceed 13.4 V. Resistors R6, R16, R17,
Zener diode VR1, and transistor Q3 form a shunt regulator that
prevents the supply voltage to IC U1 from exceeding 12 V.
Capacitors C8, C18 and C20 filter the supply voltage and
provide decoupling to ensure reliable operation of IC U1. Diode
D5 prevents destruction of U1 if the auxiliary input is inadvertently
connected reverse polarity.
The rectified AC input voltage of the power supply is sensed by
IC U1 using resistors R4, R5 and R19. The capacitor C12 filters
any noise on this signal.
Divider network comprising of resistors R9, R10, R11, R12, R13,
and R14 are used to scale the output voltage and provide
feedback to IC U1. The circuit comprising of diode D4,
transistor Q1, Q2 and the resistors R12 and R13 form a non-
linear feedback circuit which improves the load transient
response by improving the response time of the PFC circuit.
Resistor R7, R8, R15, and capacitors C13 and C17 are required
for shaping the loop response of the feedback network. The
combination of resistor R8 and capacitor C13 provide a low
frequency zero and the resistor R15 and capacitor C13 form a
low frequency pole.
R5
1%
R4
1%
1%
PFS714EG
HiperPFS
50 V
C12
1.38 mH
L5
U1
1N5408
D
S
D1
CONTROL
V
G
STTH8S06D
VCC
10 nF
C11
50 V
FB
D2
BAV116
130 V
2 kΩ
25 V
R7
D3
C18
1 µF
3.01 kΩ
4.7 µF
1N4148
1%
25 V
R8
C13
MMBT4401
D4
Q1
57.6 kΩ
160 kΩ
2.21 kΩ
1.5 MΩ
732 kΩ
1.6 MΩ
R14
R15
R11
R10
R13
1%
1%
1%
1%
1%
R9
2.21 kΩ
R12
1%
100 nF
470 pF
200 V
100 V
C16
C17
10 nF
C21
1 kV
www.powerint.com
10 nF
C14
1 kV
PI-6197-111110
270 µF
450 V
C15
OUT
DC
380 VDC
+