AN3065
Application note
100 W transition-mode PFC pre-regulator with the L6563S
Introduction
This application note describes a demonstration board based on the transition-mode PFC
controller L6563S and presents the results of its bench demonstration. The board
implements a 100 W, wide-range mains input, PFC pre-conditioner suitable for ballast,
adapters, flatscreen displays, and all SMPS having to meet the IEC61000-3-2 or the JEITAMITI regulation.
The L6563S is a current-mode PFC controller operating in transition mode (TM) and
implementing an internal high-voltage startup circuitry.
Figure 1.
September 2010
EVL6563S-100W: L6563S 100W TM PFC demonstration board
Doc ID 16279 Rev 2
1/33
www.st.com
Contents
AN3065
Contents
1
Main characteristics and circuit description . . . . . . . . . . . . . . . . . . . . . 4
2
Electrical diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3
Bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4
Test results and significant waveforms . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1
Harmonic content measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2
Inductor current in TM and L6563S THD optimizer . . . . . . . . . . . . . . . . . 12
4.3
Voltage feed-forward and brownout function . . . . . . . . . . . . . . . . . . . . . . 15
4.4
Startup operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.5
PFC_OK pin and feedback failure (open loop) protection . . . . . . . . . . . . 20
4.6
TBO (tracking boost option) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.7
Power management and housekeeping functions . . . . . . . . . . . . . . . . . . 23
5
Layout hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
6
EMI filtering and conducted EMI pre-compliance measurements . . . 27
7
PFC coil specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
7.1
General description and characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 29
7.2
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
7.3
Electrical diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
7.4
Winding characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7.5
Mechanical aspect and pin numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7.6
Unit identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
9
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
2/33
Doc ID 16279 Rev 2
AN3065
List of figures
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
Figure 21.
Figure 22.
Figure 23.
Figure 24.
Figure 25.
Figure 26.
Figure 27.
Figure 28.
Figure 29.
Figure 30.
Figure 31.
Figure 32.
Figure 33.
Figure 34.
Figure 35.
Figure 36.
Figure 37.
Figure 38.
Figure 39.
Figure 40.
EVL6563S-100W: L6563S 100W TM PFC demonstration board . . . . . . . . . . . . . . . . . . . . . 1
EVL6563S-100W TM PFC demonstration board: electrical schematic . . . . . . . . . . . . . . . . 6
EVL6563S-100W TM PFC: compliance to EN61000-3-2 standard . . . . . . . . . . . . . . . . . . 10
EVL6563S-100W TM PFC: compliance to JEITA-MITI standard . . . . . . . . . . . . . . . . . . . . 10
EVL6563S-100W TM PFC: input current waveform at 230 V, 50 Hz, 100 W load . . . . . . . 11
EVL6563S-100W TM PFC: input current waveform at 100 V, 50 Hz, 100 W load . . . . . . . 11
EVL6563S-100W TM PFC: power factor vs. output power. . . . . . . . . . . . . . . . . . . . . . . . . 11
EVL6563S-100W TM PFC: THD vs. output power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
EVL6563S-100W TM PFC: efficiency vs. output power . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
EVL6563S-100W TM PFC: average efficiency acc. to ES-2 . . . . . . . . . . . . . . . . . . . . . . . 12
EVL6563S-100W TM PFC: static Vout regulation vs. output power. . . . . . . . . . . . . . . . . . 12
EVL6563H 100W TM PFC: Vds and inductor current at 100 Vac, 50 Hz, full load. . . . . . . 13
EVL6563H 100W TM PFC: Vds and inductor current at 100 Vac, 50 Hz, full load (detail). 13
EVL6563H 100W TM PFC: Vds and inductor current at 230 Vac, 50 Hz, full load. . . . . . . 14
EVL6563H 100W TM PFC: Vds and inductor current at 230 Vac, 50 Hz, full load (detail). 14
EVL6563S-100W TM PFC: Vds and inductor current at 100 Vac, 50 Hz, full load. . . . . . . 15
EVL6563S-100W TM PFC: Vds and inductor current at 230 Vac, 50 Hz, full load. . . . . . . 15
L6562A input mains surge 90 Vac to 140 Vac, no VFF input . . . . . . . . . . . . . . . . . . . . . . . 16
EVL6563S-100W TM PFC: input mains surge 90 Vac to 140 Vac . . . . . . . . . . . . . . . . . . . 16
L6562A input mains dip 140 Vac to 90 Vac, no VFF input . . . . . . . . . . . . . . . . . . . . . . . . . 17
EVL6563S-100W TM PFC: input mains dip 140 Vac to 90 Vac . . . . . . . . . . . . . . . . . . . . . 17
L6563: input current at 100 Vac, 50 Hz, CFF=0.47 µF, RFF=390 kΩ. . . . . . . . . . . . . . . . . 18
EVL6563S-100W TM PFC: input current at 100 Vac, 50 Hz, CFF=1 µF, RFF=1 MΩ . . . . 18
EVL6563S-100W TM PFC startup attempt at 80Vac, 60 Hz, full load . . . . . . . . . . . . . . . . 19
EVL6563S-100W TM PFC: startup with slow input voltage increasing, full load . . . . . . . . 19
EVL6533S-100W TM PFC: turn-off with slow input voltage decreasing, full load . . . . . . . 19
EVL6563S-100W TM PFC startup at 90 Vac, 60 Hz, full load . . . . . . . . . . . . . . . . . . . . . . 20
EVL6563S-100W TM PFC startup at 265 Vac, 50 Hz, full load . . . . . . . . . . . . . . . . . . . . . 20
EVL6563S-100W TM PFC load transient at 115 Vac, 60 Hz, full load to no load . . . . . . . 22
EVL6563S-100W TM PFC open loop at 115 Vac, 60 Hz, full load . . . . . . . . . . . . . . . . . . . 22
L6563S on/off control by a cascaded converter controller via the PFC_OK or RUN pin . . 23
Interface circuits that let the L6563S switch on or off a PWM controller, not latched . . . . . 24
Interface circuits that let the L6563S switch on or off a PWM controller, latched . . . . . . . . 24
EVL6563S-100W TM PFC PCB layout (SMT side view) . . . . . . . . . . . . . . . . . . . . . . . . . . 26
EVL6563S-100W TM PFC CE peak measurement at 100 Vac, 50 Hz, full load, phase . . 27
EVL6563S-100W TM PFC CE peak measurement at 100 Vac, 50 Hz, full load, neutral . . 27
EVL6563S-100W TM PFC CE peak measurement at 230 Vac, 50 Hz, full load, phase . . 28
EVL6563S-100W TM PFC CE peak measurement at 230 Vac, 50 Hz, full load, neutral . . 28
Electrical diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Top view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Doc ID 16279 Rev 2
3/33
Main characteristics and circuit description
1
AN3065
Main characteristics and circuit description
The main characteristics of the SMPS are listed below:
●
Line voltage range: 90 to 265 Vac
●
Minimum line frequency (fL): 47 Hz
●
Regulated output voltage: 400 V
●
Rated output power: 100 W
●
Maximum 2fL output voltage ripple: 20 V pk-pk
●
Hold-up time: 10 ms (VDROP after hold-up time: 300 V)
●
Minimum switching frequency: 40 kHz
●
Minimum estimated efficiency: 92% (at Vin = 90 Vac, Pout = 100 W)
●
Maximum ambient temperature: 50 °C
●
PCB type and size: single side, 35 µm, CEM-1, 90 x 83 mm
This demonstration board implements a power factor correction (PFC) pre-regulator,100 W
continuous power, on a regulated 400 V rail from a wide-range mains voltage and provides
for the reduction of the mains harmonics, allowing to meet the European EN61000-3-2 or
the Japanese JEITA-MITI standard. The regulated output voltage is typically the input for the
cascaded isolated DC-DC converter that provides the output rails required by the load.
The board is designed to allow full-load operation in still air.
The power stage of the PFC is a conventional boost converter, connected to the output of
the rectifier bridge D1. It is completed by the coil L2, the diode D3 and the capacitor C6. The
boost switch is represented by the power MOSFET Q1. The NTC R1 limits the inrush
current at switch-on. It has been connected on the DC rail, in series to the output electrolytic
capacitor, in order to improve the efficiency during low line operation because the RMS
current flowing into the output stage is lower than current flowing into the input one at the
same input voltage, thus increasing efficiency. The board is equipped with an input EMI filter
necessary to filter the commutation noise coming from the boost stage.
At startup the L6563S is powered by the capacitor C11 that is charged via the resistors R7
and R16. Then the L2 secondary winding and the charge pump circuit (C7, R4, D4 and D5)
generate the Vcc voltage powering the L6563S during normal operation. The L2 secondary
winding is also connected to the L6563S pin #11 (ZCD) through the resistor R5. Its purpose
is supply the information that L2 has demagnetized, needed by the internal logic for
triggering a new switching cycle.
The divider R9, R12, R17 and R19 provides the L6563S multiplier with the information of the
instantaneous mains voltage that is used to modulate the peak current of the boost.
The resistors R2, R8, R10 with R13 and R14 are dedicated to sense the output voltage and
feed back to the L6563S the information necessary to regulate the output voltage. The
components C9, R18 and C8 constitute the error amplifier compensation network necessary
to keep the required loop stability.
The peak current is sensed by resistors R25 and R26 in series to the MOSFET and signal is
fed into pin #4 (CS) of the L6563S via the filter composed of R24 and C15.
C13, R27 and R32 connected to pin #5 (VFF) complete an internal peak-holding circuit that
derives the information on the RMS mains voltage. The voltage signal at this pin, a DC level
equal to the peak voltage on pin #3 (MULT), is fed to a second input to the multiplier for the
4/33
Doc ID 16279 Rev 2
AN3065
Main characteristics and circuit description
1/V2 function necessary to compensate the control loop gain dependence on the mains
voltage. Additionally, pin #10 (RUN) is connected to pin# 5 (VFF) through a resistor divider
R27 and R32, providing a voltage threshold for brownout protection (AC mains
undervoltage). A voltage below 0.8 V shuts down (not latched) the IC and brings its
consumption to a considerably lower level. The L6563S restarts as the voltage at the pin
rises above 0.88 V.
The divider R3, R6, R11 and R15 provides the L6563S pin #7 (PFC_OK) with the
information regarding the output voltage level. It is required by the L6563S output voltage
monitoring and disables functions used for PFC protection purposes.
If the voltage on pin #7 exceeds 2.5 V, the IC stops switching and restarts as the voltage on
the pin falls below 2.4 V implementing the so-called dynamic OVP, which prevents an
excessive output voltage in case of transients, because of the slow response of the error
amplifier. However, if contemporaneously the voltage of the INV pin falls below 1.66 V (typ.),
a feedback failure is assumed. In this case the device is latched off. Normal operation can
be resumed only by cycling Vcc, bringing its value lower than 6 V before rising up to the
turn-on threshold.
Additionally If the voltage on pin #7 (PFC_OK) is tied below 0.23 V, the L6563S is shut
down. To restart operation of the L6563S the voltage on pin #7 (PFC_OK) has to increase
above 0.27 V. This function can be used as a remote on/off control input.
To allow interfacing of the board with a D2D converter, the connector J3 allows powering the
L6563S with an external Vcc and also manages failure or abnormal conditions via the pins
PWM_LATCH and PWM_STOP. The L6563S can be also disabled or enabled to manage
properly light load or failure by the D2D via the PFC_OK pin (#7), available at pin #5 of J3
(ON/OFF). For further details please see Section 4.7.
Doc ID 16279 Rev 2
5/33
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EVL6563S-100W TM PFC demonstration board: electrical schematic
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AN3065
!-V
Bill of material
Table 1.
EVL6563S-100W TM PFC demonstration board bill of material
Doc ID 16279 Rev 2
Part type/part value
Case/package
Description
Supplier
C1
470N
DWG
X2 - FLM CAP - R46-I 3470--M1-
ARCOTRONICS
C4
470N
DWG
X2 - FLM CAP - R46-I 3470--M1-
ARCOTRONICS
C2
2N2
DWG
Y1 - SAFETY CAP. DE1E3KX222M
muRata
C3
2N2
DWG
Y1 - SAFETY CAP. DE1E3KX222M
muRata
C5
470N - 400 V
DWG
400V - FLM CAP - B32653A4474
EPCOS
C6
47 µF - 450 V
Dia. 18 x 31.5 mm
450 V - ALUMINIUM ELCAP - ED SERIES - 105°C
NIPPON-CHEMICON
C7
4N7
1206
100 V CERCAP - general purpose
AVX
C8
680N
1206
25 V CERCAP - general purpose
AVX
C9
68N
0805
50 V CERCAP - general purpose
AVX
C10
100N
1206
50 V CERCAP - general purpose
AVX
C11
47 µF-50 V
Dia. 5 x 10 mm
50 V - aluminium ELCAP - YXF series - 105°C
Rubycon
C12
2N2
1206
50 V CERCAP - general purpose
AVX
C16
2N2
1206
50 V CERCAP - general purpose
AVX
C13
1 µF
0805
25 V CERCAP - general purpose
AVX
C14
2N2
0805
50 V CERCAP - general purpose
AVX
C15
220 pF
0805
50 V CERCAP - general purpose
AVX
D1
GBU4J
STYLE GBU
Single phase bridge rectifier
VISHAY
D2
1N4005
DO - 41
Rectifier - general purpose
VISHAY
D3
STTH2L06
DO - 41
Ultrafast high-voltage rectifier
STMicroelectronics
D4
LL4148
MINIMELF
High-speed signal diode
VISHAY
D5
BZX79-C18
DO - 35
Zener diode
VISHAY
D6
N.M.
MINIMELF
Not mounted
AN3065
Des.
Bill of material
7/33
3
EVL6563S-100W TM PFC demonstration board bill of material (continued)
Doc ID 16279 Rev 2
Part type/part value
Case/package
Description
Supplier
F1
FUSE 4 A
DWG
Fuse T4A - time delay
Wichmann
HS1
HEAT-SINK
DWG
Heatsink for D1& Q1
JP1
WIRE JUMPER
Bare copper wire jumper
JP2
N.M.
NOT MOUNTED
J1
MKDS 1,5/ 3-5,08
DWG
PCB term. block, screw conn., pitch 5 mm - 3 W
PHOENIX CONTACT
J2
MKDS 1,5/ 2-5,08
DWG
PCB term. block, screw conn., pitch 5 mm - 2 W
PHOENIX CONTACT
J3
CON5
PCB term. block, pitch 2.5 mm - 5 W
MOLEX
L1
HF2826-203Y1R5-T01
DWG
Input EMI filter - 20 mH-1.5 A
TDK
L2
SRW2620PQ-X22V102
DWG
PFC inductor - 0.52 mH (X08141-01-B)
TDK
Q1
STF7NM50N
TO-220FP
N-Channel power MOSFET
STMicroelectronics
R1
NTC 2R5-S237
DWG
NTC RESISTOR P/N B57237S0259M000
EPCOS
R2
1M0
1206
SMD standard film RES - 1/4 W - 1% - 100 ppm/°C
VISHAY
R8
1M0
1206
SMD standard film RES - 1/4 W - 1% - 100 ppm/°C
VISHAY
R10
1M0
1206
SMD standard film RES - 1/4 W - 1% - 100 ppm/°C
VISHAY
R3
3M3
1206
SMD standard film RES - 1/4 W - 1% - 100 ppm/°C
VISHAY
R6
3M3
1206
SMD standard film RES - 1/4 W - 1% - 100 ppm/°C
VISHAY
R4
100 Ω
1206
SMD standard film RES - 1/4 W - 5% - 250 ppm/°C
VISHAY
R5
68 kΩ
1206
SMD standard film RES - 1/4 W - 1% - 100 ppm/°C
VISHAY
R7
180 kΩ
1206
SMD standard film RES - 1/4 W - 5% - 250 ppm/°C
VISHAY
R16
180 kΩ
1206
SMD standard film RES - 1/4 W - 5% - 250 ppm/°C
VISHAY
R9
2M2
1206
SMD standard film RES - 1/4 W - 1% - 100 ppm/°C
VISHAY
R11
2M2
1206
SMD standard film RES - 1/4 W - 1% - 100 ppm/°C
VISHAY
R12
2M2
1206
SMD standard film RES - 1/4 W - 1% - 100 ppm/°C
VISHAY
R17
2M2
1206
SMD standard film RES - 1/4 W - 1% - 100 ppm/°C
VISHAY
R13
62 kΩ
0805
SMD standard film RES - 1/8 W - 1% - 100 ppm/°C
VISHAY
Bill of material
8/33
Des.
AN3065
Table 1.
EVL6563S-100W TM PFC demonstration board bill of material (continued)
Doc ID 16279 Rev 2
Des.
Part type/part value
Case/package
Description
Supplier
R14
27 kΩ
0805
SMD standard film RES - 1/8 W - 1% - 100 ppm/°C
VISHAY
R15
51 kΩ
1206
SMD standard film RES - 1/4 W - 1% - 100 ppm/°C
VISHAY
R18
82 kΩ
0805
SMD standard film RES - 1/8 W - 5% - 250 ppm/°C
VISHAY
R19
51 kΩ
1206
SMD standard film RES - 1/4 W - 5% - 250 ppm/°C
VISHAY
R20
N.M.
0805
Not mounted
R21
27 Ω
1206
SMD standard film RES - 1/4 W - 5% - 250 ppm/°C
VISHAY
R22
100 kΩ
0805
SMD standard film res - 1/8 W - 5% - 250 ppm/°C
VISHAY
R23
N.M.
0805
R24
220 Ω
PTH
SFR25 axial stand. film RES - 0.4W - 5% - 250 ppm/°C
VISHAY
R25
0.47 Ω
PTH
SFR25 axial stand. film RES - 0.4W - 5% - 250 ppm/°C
VISHAY
R26
0.68 Ω
PTH
SFR25 axial stand. film RES - 0.4 W - 5% - 250 ppm/°C
VISHAY
R27
56 kΩ
1206
SMD standard film RES - 1/4 W - 1% - 100 ppm/°C
VISHAY
R28
1 kΩ
1206
SMD standard film RES - 1/4 W - 5% - 250 ppm/°C
VISHAY
R29
1 kΩ
1206
SMD standard film RES - 1/4 W - 5% - 250 ppm/°C
VISHAY
R30
1 kΩ
1206
SMD standard film RES - 1/4 W - 5% - 250 ppm/°C
VISHAY
R31
10 Ω
1206
SMD standard film RES - 1/4 W - 5% - 250 ppm/°C
VISHAY
R32
1M0
0805
SMD standard film RES - 1/8 W - 1% - 250 ppm/°C
VISHAY
U1
L6563S
SO-14
Enhanced transition-mode PFC controller
STMicroelectronics
Bill of material
9/33
Table 1.
VISHAY
AN3065
Test results and significant waveforms
AN3065
4
Test results and significant waveforms
4.1
Harmonic content measurement
One of the main purposes of a PFC pre-conditioner is the correction of input current
distortion, decreasing the harmonic contents below the limits of the relevant regulations.
Therefore, this demonstration board has been tested according to the European standard
EN61000-3-2 Class-D and Japanese standard JEITA-MITI Class-D, at full load at both the
nominal input voltage mains.
The circuit is able to reduce the harmonics well below the limits of both regulations from full
load down (measurements are shown in Figure 3 and 4) to light load. Please note that all
measures and waveforms have been done using a Pi-filter for filtering the noise coming from
the circuit, using a 20 mH common-mode choke and two 470NF-X2 filter capacitors.
Figure 3.
EVL6563S-100W TM PFC:
compliance to EN61000-3-2
standard
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Figure 4.
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Vin = 230 Vac - 50 Hz
Vin = 100 Vac - 50 Hz
Pout = 100 W
Pout = 100 W
THD = 2.31 %
THD = 2.30 %
PF = 0.982
PF = 0.999
10/33
-(,7$0,7,&ODVV'OLPLWV
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EVL6563S-100W TM PFC:
compliance to JEITA-MITI standard
Doc ID 16279 Rev 2
AN3065
Test results and significant waveforms
For user reference, waveforms of the input current and voltage at the nominal input voltage
mains and nominal load conditions are shown in Figure 5 and 6.
Figure 5.
EVL6563S-100W TM PFC: input
current waveform at 230 V, 50 Hz,
100 W load
Figure 6.
EVL6563S-100W TM PFC: input
current waveform at 100 V, 50 Hz,
100 W load
CH1: Vout
CH1: Vout
CH2: V bridge
CH2: V bridge
CH4: I_AC
CH4: I_AC
The power factor (PF) and the total harmonic distortion (THD) have been measured too and
the results are shown in Figure 7 and 8. As visible, the PF remains close to unity throughout
the input voltage mains and the total harmonic distortion is very low.
Figure 7.
EVL6563S-100W TM PFC: power
factor vs. output power
Figure 8.
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Test results and significant waveforms
AN3065
The measured efficiency shown in Figure 9, measured according to the ES-2 requirements,
is very good at all load and line conditions. At full load it is always higher than 93%, making
this design suitable for high efficiency power supplies. The average efficiency, calculated
according to the ES-2 requirements, at different nominal mains voltages is shown in
Figure 10.
Figure 9.
EVL6563S-100W TM PFC: efficiency Figure 10. EVL6563S-100W TM PFC: average
vs. output power
efficiency acc. to ES-2
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Figure 11. EVL6563S-100W TM PFC: static
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The measured output voltage at different line and static load conditions is shown in
Figure 11. As visible, the voltage is very stable over the entire input voltage and output load
range.
4.2
Inductor current in TM and L6563S THD optimizer
The following figures show the waveforms relevant to the inductor current at different voltage
mains. As visible in Figure 12 and 13 the peak inductor current waveform over a line halfperiod follows the MULT (pin #3) at both input mains voltages and therefore the line current
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Test results and significant waveforms
is in phase with the input AC voltage, giving low distortion of the current waveform and high
power factor. On both the drain voltage traces, close to the zero-crossing points of the sine
wave, it is possible to note the action of the THD optimizer embedded in the L6563S. It is a
circuit that minimizes the conduction dead-angle of the AC input current near the zerocrossings of the line voltage (crossover distortion). In this way, the THD (total harmonic
distortion) of the current is considerably reduced. A major cause of this distortion is the
inability of the system to transfer energy effectively when the instantaneous line voltage is
very low. This effect is magnified by the high-frequency filter capacitor placed after the
bridge rectifier, which retains some residual voltage that causes the diodes of the bridge
rectifier to be reverse-biased and the input current flow to temporarily stop. To overcome this
issue the device forces the PFC pre-regulator to process more energy near the line voltage
zero-crossings as compared to that commanded by the control loop. This results in both
minimizing the time interval where energy transfer is lacking and fully discharging the highfrequency filter capacitor after the bridge. Essentially, the circuit artificially increases the ONtime of the power switch with a positive offset added to the output of the multiplier in the
proximity of the line voltage zero-crossings. This offset is reduced as the instantaneous line
voltage increases, so that it becomes negligible as the line voltage moves toward the top of
the sinusoid. Furthermore the offset is modulated by the voltage on the VFF pin so as to
have little offset at low line, where energy transfer at zero-crossings is typically quite good,
and a larger offset at high line where the energy transfer gets worse.
To obtain maximum benefit from the THD optimizer circuit, the high-frequency filter
capacitors after the bridge rectifier should be minimized, compatibly with EMI filtering needs.
A large capacitance, in fact, introduces a conduction dead-angle of the AC input current in
itself, thus reducing the effectiveness of the optimizer circuit.
Figure 12. EVL6563H 100W TM PFC: Vds and
inductor current at 100 Vac, 50 Hz,
full load
Figure 13. EVL6563H 100W TM PFC: Vds and
inductor current at 100 Vac, 50 Hz,
full load (detail)
CH1: Q1 drain voltage
CH4: Q1 drain voltage
CH2: MULT voltage - Pin #3
CH2: MULT voltage - pin #3
CH4: L2 inductor current
CH1: L2 inductor current
In Figure 13 and 15 the detail of the waveforms at switching frequency allows measuring the
operating frequency and the current peak at top of the input sine wave during operation at
100 Vac and 230 Vac. The multiplier waveform has been captured as a reference.
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Figure 14. EVL6563H 100W TM PFC: Vds and
inductor current at 230 Vac, 50 Hz,
full load
Figure 15. EVL6563H 100W TM PFC: Vds and
inductor current at 230 Vac, 50 Hz,
full load (detail)
CH4: Q1 drain voltage
CH4: Q1 drain voltage
CH2: MULT voltage - pin #3
CH2: MULT voltage - pin #3
CH1: L2 inductor current
CH1: L2 inductor current
In Figure 16 and 17 the detail of the waveforms at switching frequency shows the operation
of transition-mode control. Once the inductor has transferred all the stored energy, a falling
edge on the ZCD pin (pin #11) is detected and it will trigger a new on-time by setting the
gate drive high. As soon as the current signal on the CS pin (pin #4) reaches the level
programmed by the internal multiplier circuitry according to the input mains instantaneous
voltage and the error amplifier output level, the gate drive is set low and MOSFET
conduction is stopped. A following off-time will transfer the energy stored in the inductor into
the output capacitor and to the load. At the end of the current conduction a new
demagnetization will be detected by the ZCD that will provide for a new on-time of the
MOSFET.
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Test results and significant waveforms
Figure 16. EVL6563S-100W TM PFC: Vds and
inductor current at 100 Vac, 50 Hz,
full load
Figure 17. EVL6563S-100W TM PFC: Vds and
inductor current at 230 Vac, 50 Hz,
full load
CH1: GD - pin #13
CH1: GD - pin #13
CH2: ZCD - pin #11
CH2: ZCD - pin #11
CH3: CS - pin #4
CH3: CS - pin #4
CH4: L2 inductor current
CH4: L2 inductor current
4.3
Voltage feed-forward and brownout function
The power stage gain of PFC pre-regulators varies with the square of the RMS input voltage
as well as the crossover frequency fc of the overall open-loop gain because the gain has a
single pole characteristic. This leads to large trade-offs in the design. For example, setting
the gain of the error amplifier to get fc = 20 Hz at 264 Vac means having fc≈ 4 Hz at 88 Vac,
resulting in a sluggish control dynamics. Additionally, the slow control loop causes large
transient current flow during rapid line or load changes that are limited by the dynamics of
the multiplier output. This limit is considered when selecting the sense resistor to let the full
load power pass under minimum line voltage conditions, with some margin. A fixed current
limit allows excessive power input at high line, whereas a fixed power limit requires the
current limit to vary inversely with the line voltage.
Voltage feed-forward can compensate for the gain variation with the line voltage and allow
overcoming all of the above-mentioned issues. It consists of deriving a voltage proportional
to the input RMS voltage, feeding this voltage into a squarer/divider circuit (1/V2 corrector)
and providing the resulting signal to the multiplier that generates the current reference for
the inner current control loop.
In this way, a change of the line voltage causes an inversely proportional change of the half
sine amplitude at the output of the multiplier (if the line voltage doubles, the amplitude of the
multiplier output is halved and vice versa) so that the current reference is adapted to the new
operating conditions with (ideally) no need for invoking the slow dynamics of the error
amplifier. Additionally, the loop gain is constant throughout the input voltage range, which
improves significantly dynamic behavior at low line and simplifies loop design.
Actually, with other PFCs embedding the voltage feed-forward, deriving a voltage
proportional to the RMS line voltage implies a form of integration, which has its own time
constant. If it is too small, the voltage generated will be affected by a considerable amount of
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Test results and significant waveforms
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ripple at twice the mains frequency that will cause distortion of the current reference
(resulting in high THD and poor PF). If it is too large, there will be a considerable delay in
setting the right amount of feed-forward, resulting in excessive overshoot and undershoot of
the pre-regulator's output voltage in response to large line voltage changes. Clearly a tradeoff was required.
The L6563S implements an innovative voltage feed-forward which, with a technique that
overcomes this time constant trade-off issue whichever voltage change occurs (both surges
and drops) on the mains. A capacitor CFF (C13) and a resistor RFF (R27 + R32), both
connected to the VFF (pin #5), complete an internal peak-holding circuit that provides a DC
voltage equal to the peak of the rectified sine wave applied on pin MULT (pin #3). In this way,
in case of sudden line voltage rise, CFF is rapidly charged through the low impedance of the
internal diode. In case of line voltage drop, an internal "mains drop" detector enables a low
impedance switch which suddenly discharges CFF avoiding a long settling time before
reaching the new voltage level. Consequently, an acceptably low steady-state ripple and low
current distortion can be achieved without any considerable undershoot or overshoot on the
preregulator's output like in systems with no feed-forward compensation.
In Figure 19 we find the behavior of the EVL6563S-100W demonstration board in case of an
input voltage surge from 90 to 140 Vac. As shown, it is evident that the VFF function
provides for the stability of the output voltage which is not affected by the input voltage
surge. In fact, thanks to the VFF function, the compensation of the input voltage variation is
very fast and the output voltage remains stable at its nominal value. The opposite is
confirmed in Figure 18 where the behavior of a PFC using the L6562A and delivering same
output power is shown. The controller cannot compensate a mains surge and the output
voltage stability is guaranteed by the feedback loop only. Unfortunately, as previously stated,
its bandwidth is narrow and thus the output voltage has a significant deviation from the
nominal value. The circuit has the same behavior in case of a mains surge at any input
voltage, and it is also not affected if the input mains surge happens at any point along the
input sine wave.
Figure 18. L6562A input mains surge 90 Vac to Figure 19. EVL6563S-100W TM PFC: input
140 Vac, no VFF input
mains surge 90 Vac to 140 Vac
CH1: Vout
CH1: Vout
CH2: MULT (pin #3)
CH2: MULT (pin #3)
CH4: I_AC
CH3: VFF (pin #5)
CH4: I_AC
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Test results and significant waveforms
Figure 21 shows the circuit behavior in case of a mains dip. As previously described, the
internal circuitry has detected the decreasing of the mains voltage and it has activated the
CFF internal fast discharge. As visible, in that case the output voltage changes but in few
mains cycles it comes back to the nominal value. The situation is different if we check the
performance of a controller without the VFF function. Figure 20 shows the behavior of a PFC
using the L6562A delivering similar output power. In case of a mains dip from 140 Vac to 90
Vac, the output voltage variation is not very different, but the output voltage requires a longer
time to restore the original value.
Testing with a wider voltage variation (e.g. 265 Vac to 90 Vac), the output voltage variation of
a PFC without the voltage feed-forward fast discharge is emphasized even more.
Figure 20. L6562A input mains dip 140 Vac to Figure 21. EVL6563S-100W TM PFC: input
90 Vac, no VFF input
mains dip 140 Vac to 90 Vac
CH1: Vout
CH1: Vout
CH2: MULT (pin #3)
CH2: MULT (pin #3)
CH4: I_AC
CH3: VFF (pin #5)
CH4: I_AC
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Test results and significant waveforms
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Comparing Figure 22 and 23 we can see that the input current of the latter has a better
shape and the 3rd harmonic current distortion is not noticeable. This demonstrates the
benefits of the new voltage feed-forward circuit integrated in the L6563S. Allowing a fast
response to mains disturbances but using a quite long VFF time constant provides also very
low THD and high PF at same time as confirmed by the measurements below.
Figure 22. L6563: input current at 100 Vac, 50 Figure 23. EVL6563S-100W TM PFC: input
Hz, CFF=0.47 µF, RFF=390 kΩ
current at 100 Vac, 50 Hz, CFF=1 µF,
RFF=1 MΩ
THD = 5.15%, 3RD harmonic = 43 mA
THD = 2.30%, 3RD harmonic = 25.8 mA
CH2: MULT (pin #3)
CH2: MULT (pin #3)
CH3: VFF (pin #5)
CH3: VFF (pin #5)
CH4: I_AC
CH4: I_AC
Another function integrated in the L6563S is the brownout protection, which is basically a
non-latched shutdown function that must be activated when a mains undervoltage condition
is detected. This abnormal condition may cause overheating of the primary power section
due to an excess of RMS current. Brownout can also occur because the PFC pre-regulator
works in open loop and this could be dangerous to the PFC stage itself and the downstream
converter, should the input voltage return abruptly to its rated value. Another problem is the
spurious restarts that may occur during converter power down and that cause the output
voltage of the converter not to decay to zero monotonically. For these reasons it is usually
preferable to shutdown the device in case of brownout.
Brownout function is done through sensing of the input mains by an internal comparator
connected to RUN (pin #10), connected via a divider to VFF (pin #5) which delivers a voltage
signal proportional to the input mains. The enable and disable thresholds at which the
L6563S will start or stop the operation can be adjusted by modifying that divider ratio. For
additional information please see [2 in Section 8: References].
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Test results and significant waveforms
Figure 24. EVL6563S-100W TM PFC startup
attempt at 80Vac, 60 Hz, full load
CH1: PFC output voltage
CH2: Vcc voltage (pin #14)
CH3: RUN (pin #10)
CH4: gate drive (pin #13)
In Figure 24 a startup tentative below the threshold is captured. As visible at startup the
RUN pin does not allow PFC startup.
In Figure 25 and 26 the waveforms of the circuit during operation of the brownout protection
are captured. In both cases the mains voltage was increased or decreased slowly. As visible
both at turn-on or turn-off there are no bouncing or starting attempts by the PFC converter.
Figure 25. EVL6563S-100W TM PFC: startup
Figure 26. EVL6533S-100W TM PFC: turn-off
with slow input voltage increasing,
with slow input voltage decreasing,
full load
full load
CH1: PFC output voltage
CH1: PFC output voltage
CH2: Vcc (pin #14)
CH2: Vcc (pin #14)
CH3: RUN (pin #10)
CH3: RUN (pin #10)
CH4: Gate drive (pin #13)
CH4: Gate drive (pin #13)
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Test results and significant waveforms
4.4
AN3065
Startup operation
On this demonstration board the startup resistors R7 and R16 charge C10 and C11 until the
L6563S turn-on voltage threshold is reached, at which point the L6563S starts switching.
Because once the turn-on threshold is reached the Vcc consumption increases and the
current supplied by R7 and R16 is lower, the L6563S is initially supplied by the Vcc
capacitor, and then the L1 auxiliary winding provides the voltage to supply the IC.
In the following Figure 27 and 28 the waveforms during the startup of the circuit at mains
plug-in are shown. We can notice that the Vcc voltage rises up to the turn-on threshold, and
the L6563S starts operating. As mentioned previously, for a short time the energy is
supplied by the Vcc capacitor, and then the auxiliary winding with the charge pump circuit
takes over. At the same time, the output voltage rises from the peak value of the rectified
mains to the nominal value of the PFC output voltage. The good margin of the
compensation network allows a clean startup, without any large overshoot.
Figure 27. EVL6563S-100W TM PFC startup at Figure 28. EVL6563S-100W TM PFC startup at
90 Vac, 60 Hz, full load
265 Vac, 50 Hz, full load
CH1: PFC output voltage
CH1: PFC output voltage
CH2: Vcc voltage (pin #14)
CH2: Vcc voltage (pin #14)
CH3: RUN (pin #10)
CH3: RUN (pin #10)
CH4: Gate drive (pin #13)
CH4: Gate drive (pin #13)
4.5
PFC_OK pin and feedback failure (open loop) protection
During normal operation, the voltage control loop provides for the output voltage (Vout) of
the PFC pre-regulator close to its nominal value, set by the resistor ratio of the feedback
output divider. In the L6563S the PFC_OK pin has been dedicated to monitor the output
voltage with a separate resistor divider composed of R3, R6, R11 (high) and R15 (low), see
Figure 2. This divider is selected so that the voltage at the pin reaches 2.5 V if the output
voltage exceeds a preset value (VOVP), usually larger than the maximum Vout that can be
expected, also including worst-case load/line transients.
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Test results and significant waveforms
For the EVL6563S-100W we have:
●
For the EVL6563H-100W we have:
–
VO = 400 V
–
VOVP = 434 V
–
Select: R3+R4+R11 = 8.8 MΩ
then:
–
R15 = 8.8 MΩ ·2.5/(434-2.5) = 51 kΩ
Once this function is triggered, the gate drive activity is immediately stopped until the
voltage on the pin PFC_OK drops below 2.4 V. An example is given in Figure 29.
Notice that both feedback dividers connected to L6563S V_INV (pin #1) and PFC_OK (pin
#7) can be selected without any constraints. The unique criterion is that both dividers have
to sink a current from the output bus which needs to be significantly higher than the current
biasing the error amplifier and PFC_OK comparator.
The OVP function described above is able to handle "normal" overvoltage conditions, i.e.
those resulting from an abrupt load/line change or occurring at startup. In case the
overvoltage is generated by a feedback disconnection, for instance, when one of the upper
resistors of the output divider fails open, an additional circuitry detects the voltage drop of
pin INV. If the voltage on pin INV is lower than 1.66 V and at the same time OVP is active, a
feedback failure is assumed. Thus, the gate drive activity is immediately stopped, the device
is shut down, its quiescent consumption is reduced below 180 µA and the condition is
latched as long as the supply voltage of the IC is above the UVLO threshold. To restart the
system, it is necessary to recycle the input power, so that the Vcc voltage of the L6563S
goes below 6 V and that one of the PWM controllers goes below its UVLO threshold.
Note that this function offers a complete protection against not only feedback loop failures or
erroneous settings, but also against a failure of the protection itself. Either resistor of the
PFC_OK divider failing short or open or a PFC_OK pin floating results in shutting down the
IC and stopping the pre-regulator.
Moreover, the pin PFC_OK doubles its function as a non-latched IC disable. A voltage
below 0.23V shuts down the IC, reducing its consumption below 2 mA. To restart the IC,
simply let the voltage at the pin go above 0.27 V.
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Figure 29. EVL6563S-100W TM PFC load
Figure 30. EVL6563S-100W TM PFC open loop
transient at 115 Vac, 60 Hz, full load
at 115 Vac, 60 Hz, full load
to no load
CH1: PFC output voltage
CH1: PFC output voltage
CH2: PFC_OK (pin #7)
CH2: Vcc (pin #14)
CH3: gate drive (pin #13)
CH3: gate drive (pin #13)
CH4: Iout
CH4: PWM_LATCH (pin #8)
The event of an open loop is captured in Figure 30. We can notice the protection
intervention, latching the operation of the L6563S. As mentioned previously, to restart the
system the input power must be recycled.
4.6
TBO (tracking boost option)
To use the TBO function on L6563S, a dedicated input of the multiplier is available on pin #6
(TBO). The function can be implemented by simply connecting a resistor (RT) between the
TBO pin and ground.
Usually, in traditional PFC stages, the DC output voltage is regulated at a fixed value
(typically 400 V) but in some applications, it may be advantageous to regulate the PFC
output voltage with the "tracking boost" or "follower boost" approach. In this way the circuit
with the TBO function provides better efficiency and thanks to the lower differential voltage
across the boost inductor, the value of L2 can be reduced as compared to the same circuit
without the TBO function.
The TBO pin presents a DC level equal to the peak of the MULT pin voltage and is
representative of the mains RMS voltage. The resistor defines a current, equal to
V(TBO)/RT, that is internally 1:1 mirrored and sunk from pin INV (pin 1) input of the error
amplifier. In this way, when the mains voltage increases, the voltage at the TBO pin
increases also as well as the current flowing through the resistor connected between TBO
and GND. Then a larger current will be sunk by the INV pin and the output voltage of the
PFC pre-regulator will be forced to go higher. Obviously, the output voltage will move in the
opposite direction if the input voltage decreases.
To avoid an undesired output voltage rise should the mains voltage exceed the maximum
specified value, the voltage at the TBO pin is clamped at 3 V. By properly selecting the
multiplier bias it is possible to set the maximum input voltage above which input-to-output
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Test results and significant waveforms
tracking ends and the output voltage becomes constant. If this function is not used, leave
the pin open. The device will regulate at a fixed output voltage.
4.7
Power management and housekeeping functions
A special feature of the L6563S is that it facilitates the implementation of the "housekeeping"
circuitry needed to coordinate the operation of the PFC stage with the cascaded DC-DC
converter. The functions implemented by the housekeeping circuitry ensure that transient
conditions like power-up or power-down sequencing or failures of either power stage are
properly handled. The L6563S provides pins to do that.
As already mentioned, one communication line between the L6563S and the PWM
controller of the cascaded DC-DC converter is the PWM_LATCH (pin #8), which is normally
open when the PFC works properly. It goes high if the L6563S loses control of the output
voltage (because of a failure of the control loop) with the aim of latching off the PWM
controller of the cascaded DC-DC converter as well.
A second communication line can be established via the disable function included in the
RUN pin. Typically, this line is used to allow the PWM controller of the cascaded DC-DC
converter to shut down the L6563S in case of light load, in order to minimize the no-load
input consumption of the power supply.
Figure 31. L6563S on/off control by a cascaded converter controller via the PFC_OK
or RUN pin
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The third communication line is the PWM_STOP (pin #9), which works in conjunction with
the RUN (pin#10). The purpose of the PWM_STOP pin is to inhibit the PWM activity of both
the PFC stage and the cascaded DC-DC converter. The pin is an open collector, normally
open, that goes low if the device is disabled by a voltage lower than 0.8 V on the RUN (pin
#10). It is important to point out that this function works correctly in systems where the PFC
stage is the master and the cascaded DC-DC converter is the slave or, in other words,
where the PFC stage starts first, powers both controllers and enables/disables the operation
of the DC-DC stage. This function is quite flexible and can be used in different ways. In
systems comprising an auxiliary converter and a main converter (e.g. a desktop PC's silver
box or hi-end flatscreen TV or monitor), where the auxiliary converter also powers the
controllers of the main converter, the RUN (pin #10) can be used to start and stop the main
converter. In the simplest case, to enable/disable the PWM controller the PWM_STOP (pin
#9) can be connected to either the output of the error amplifier or, if the chip is provided with
it, to its soft-start pin.
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Test results and significant waveforms
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The EVL6563S-100W offers the possibility to test these functions by connecting it to the
cascaded converter via the series resistors R28, R29, R30. Regarding the PWM_STOP (pin
#9) pin that is an open collector type, if it needs a pull-up resistor, please connect it close to
the cascaded PWM for better noise immunity.
Figure 32. Interface circuits that let the L6563S Figure 33. Interface circuits that let the L6563S
switch on or off a PWM controller,
switch on or off a PWM controller,
not latched
latched
/.
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8
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,8
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07-2%3
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AN3065
5
Layout hints
Layout hints
The layout of any converter is a very important phase in the design process needing
attention by the design engineers like any other design phase. Even if it the layout phase
sometimes looks time-consuming, a good layout does indeed save time during the
functional debugging and the qualification phases. Additionally, a power supply circuit with a
correct layout needs smaller EMI filters or less filter stages which allows consistent cost
saving.
Converters using the L6563S do not require any special or specific layout rule, just the
general layout rules for any power converter have to be applied carefully. Basic rules are
listed here below. They can be used for other PFC circuits having any power level, working
either in transition mode or with a fixed-off time control.
1.
Keep power and signal RTN separated. Connect the return pins of components
carrying high current such as the input filter, sense resistors, or the output capacitor as
close as possible. This point is the RTN star point. A downstream converter will have to
be connected to this return point.
2.
Minimize the length of the traces relevant to the boost inductor, MOSFET drain, boost
rectifier and output capacitor.
3.
Keep signal components as close as possible to each L6563S relevant pin. Specifically,
keep the tracks relevant to the pin #1 (INV) net as short as possible. Components and
traces relevant to the error amplifier have to be placed far from traces and connections
carrying signals with high dV/dt like the MOSFET drain. For high-power converters or
very compact PCB layouts, a 10 nF capacitor connected to pin #8 (PWM_LATCH) and
pin #12 (GND) might be required to decrease the noise picked up by this pin while it is
in its high impedance status.
4.
Please connect heatsinks to power GND.
5.
Add an external shield to the boost inductor and connect it to power GND.
6.
Please connect the RTN of signal components including the feedback, PFC_OK and
MULT dividers close to the L6563S pin #14 (GND).
7.
Connect a ceramic capacitor (100÷470 nF) to pin #14 (Vcc) and pin #12 (GND), close
to the L6563S. Connect this point to the RTN star point (see rule 1).
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Layout hints
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Figure 34. EVL6563S-100W TM PFC PCB layout (SMT side view)
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6
EMI filtering and conducted EMI pre-compliance measurements
EMI filtering and conducted EMI pre-compliance
measurements
The following figures show the peak measurement of the conducted noise at full load and
nominal mains voltages for both mains lines. The limits shown in the diagrams are EN55022
class-B which is the most popular regulation for domestic equipment using a two-wire mains
connection.
It is also useful to remind that typically a PFC produces a significant differential mode noise
with respect to other topologies and therefore in case an additional margin with respect to
the limits is required, we suggest trying to increase the across-the-line (X) capacitors or the
capacitor after the rectifier bridge C5. This will be more effective and cheaper than
increasing the size of the common-mode filter coil that would filter the differential mode
noise by the leakage inductance between the two windings only.
In order to recognize if the circuit is affected by common mode or differential mode noise it is
sufficient to compare the spectrum of phase and neutral line measurements. If the two
measurements are very similar, the noise is almost totally common mode. If there is a
significant difference between the two measurement spectrums, their difference represents
the amount of differential mode noise. Of course to get a reliable comparison the two
measurements have to be done in the same conditions. If the peak measurement is used as
in the figures below, some countermeasures will have to be used, like synchronizing the
sweep of the spectrum analyzer with the input voltage. This is necessary with TM PFC
having a switching frequency that is modulated along the sine wave.
Because the differential mode produces the common mode noise by the magnetic field
induced by the current, decreasing the differential mode consequently limits the second one.
Figure 35. EVL6563S-100W TM PFC CE peak Figure 36. EVL6563S-100W TM PFC CE peak
measurement at 100 Vac, 50 Hz, full
measurement at 100 Vac, 50 Hz, full
load, neutral
load, phase
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EMI filtering and conducted EMI pre-compliance measurements
AN3065
Figure 37. EVL6563S-100W TM PFC CE peak Figure 38. EVL6563S-100W TM PFC CE peak
measurement at 230 Vac, 50 Hz, full
measurement at 230 Vac, 50 Hz, full
load, phase
load, neutral
As visible in the diagrams, in all test conditions there is a good margin of the measures with
respect to the limits. The measurements have been done in peak detection to speed up the
sweep, otherwise taking a long time. Please note that the measurements done in quasipeak or average as required by the regulation will be much lower because of the jittering
effect of the TM control that cannot be evaluated in peak detection.
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PFC coil specifications
7
PFC coil specifications
7.1
General description and characteristics
7.2
●
Applications: consumer, home appliance
●
Transformer type: open
●
Coil former: vertical type, 6+6 pins
●
Max. temp. rise: 45 °C
●
Max. operating ambient temp.: 60 °C
●
Mains insulation: N.A.
●
Unit finish: varnish
Electrical characteristics
●
Converter topology: boost, transition mode
●
Core type: PQ26/20 - PC44
●
Min. operating frequency: 40 kHz
●
Typical operating freq: 120 kHz
●
Primary inductance: 520 µH 10% at 1 kHz - 0.25 V (see note below)
●
Peak primary current: 4.2 Apk
●
RMS primary current: 1.4 Arms
Note:
Measured between pins #5 and #9
7.3
Electrical diagram
Figure 39. Electrical diagram
02)
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PFC coil specifications
7.4
AN3065
Winding characteristics
Table 2.
Winding characteristics
Pins
Winding
RMS current
Number of turns
Wire type
5-9
Primary(1)
1.4 ARMS
57.5 - fit
Multi stranded
#7 x φ 0.20 mm
11 - 3
Aux (2)
5.5 spaced
5.5 - spaced
φ 0.28 mm
1. Primary winding external insulation: 2 layers of polyester tape
2. Aux winding is wound on top of primary winding. External insulation with 2 layers of polyester tape
7.5
Mechanical aspect and pin numbering
●
Maximum height from PCB: 21.5 mm
●
Coil former type: vertical, 6+6 pins
●
TDK P/N: BPQ26/20-1112CP
●
Pins #1, 2, 4, 6, 7, 10, 12 are removed - pin 8 is for polarity key
●
External copper shield: not insulated, wound around the ferrite core, including the coil
former. It must be well adhered to the ferrite. Height is 8 mm. Connected to pin #3 by a
soldered, solid wire.
Figure 40. Top view
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Unit identification
●
Manufacturer: TDK
●
Manufacturer P/N: SRW2620PQ-X22V102
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8
References
References
1.
L6563S datasheet.
2.
AN3027 “How to design a Transition Mode PFC pre-regulator with the L6563S and
L6563H”.
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Revision history
9
AN3065
Revision history
Table 3.
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Document revision history
Date
Revision
Changes
04-Jun-2010
1
Initial release.
06-Sep-2010
2
Content reworked to improve readability.
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