cd00256070

AN3106
Application note
48 V - 130 W high-efficiency converter with PFC for LED street
lighting applications
By Claudio Spini
Introduction
The use and growing popularity of LEDS, thanks to their high efficiency and very long
lifetime, are driving the innovation of different types of lamps and contributing to the
reduction of energy consumption for internal and external lighting. Streetlight applications
require that the power supply designed to power an LED lamp must have high efficiency
and at least an equivalent lifetime in order to guarantee maintenance-free operation during
the life of the LED.
This application note describes the characteristics and features of a 130 W evaluation board
(STEVAL-ILL053V1), tailored to an LED power supply specification for street lighting. The
circuit is composed of two stages: a front-end PFC using the L6562AT and an LLC resonant
converter based on the L6599AT. The strengths of this design are very high efficiency, wide
input mains range (85 - 305 VAC) operation and long-term reliability. Because reliability
(MTBF - “mean time between failures”) in power supplies is typically affected by the high
failure rate of electrolytic capacitors unless using very expensive types, this board shows a
very innovative design approach. The board doesn't implement any electrolytic capacitors,
but uses instead film capacitors from EPCOS. Component de-rating has been also carefully
applied during the design phase, decreasing the stress of the components as recommended
by the MIL-HDBK-217D. The number of components, thanks to the use of the new devices
L6562AT and L6599AT has also been minimized, thus increasing the MTBF and optimizing
the total component cost. Thanks to the high efficiency achieved, just a small heatsink for
the PFC stage is needed, while the other power components are SMT (surface mount
technology) like most of the passive components, thus decreasing the production labor cost.
The board also has protection features in case of overload, short-circuit, open loop by each
stage or input overvoltage. For this particular application, all protections in case of
intervention have an auto-restart functionality.
Figure 1. STEVAL-ILL053V1: 130 W SMPS for LED street lighting applications
May 2016
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31
Contents
AN3106
Contents
1
Main characteristics and circuit description . . . . . . . . . . . . . . . . . . . . . 3
1.1
Power factor corrector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2
Resonant power stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3
Startup sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4
Output voltage feedback loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.5
Overload and short-circuit protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.6
Overvoltage and open loop protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2
Efficiency measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3
Input current harmonics measurement . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4
Functional check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1
PFC circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2
Half-bridge resonant LLC circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
4.3
Dynamic load operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.4
Overcurrent and overvoltage protection . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.5
Converter startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5
Thermal map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6
Conducted emission precompliance measurement . . . . . . . . . . . . . . 18
7
Bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
8
PFC coil specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
9
Transformer specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
10
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
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AN3106
1
Main characteristics and circuit description
Main characteristics and circuit description
The main features of the SMPS are listed here below:
1.1
•
Extended input mains range: 85 to 305 VAC - frequency 45 to 55 Hz
•
Output voltage: 48 V at 2.7 A
•
Long-life, electrolytic capacitors are not used
•
Mains harmonics: acc. to EN61000-3-2 Class-C
•
Efficiency at full load: better than 90% at 115 VAC
•
EMI: according to EN55022-Class-B, EN55015
•
Safety: double insulation, according to EN60950, SELV
•
Dimensions: 75 x 135 mm, 30 mm components maximum height
•
PCB: single side, 35 µm, FR-4, mixed PTH/SMT
Power factor corrector
The PFC stage, working in transition mode, acts as a preregulator and powers the resonant
stage with the output voltage of 450 V. The PFC power topology is a conventional boost
converter, connected to the output of the rectifier bridge D3. It is completed by the coil L1,
manufactured by MAGNETICA, the diode D2 and the capacitors C5, C6 and C7 in parallel.
The PFC output capacitors are film type, 5 µF - 800 V manufactured by EPCOS. Using film
capacitors to replace the typical electrolytic capacitors allows increasing considerably the
MTBF of the board.
The boost switch is represented by the power MOSFET Q2. The board is equipped with an
input EMI filter necessary to filter the commutation noise coming from the boost stage. The
PFC implements the controller L6562AT, a small and inexpensive controller that is
guaranteed for operation over a wide temperature range.
At startup, the L6562AT is supplied by the startup resistors R5, R8, R13 charging the
capacitor C13. Once the PFC begins switching, a charge pump connected to the auxiliary
winding of the PFC inductor L1 supplies both PFC and resonant controllers via a small
linear regulator implemented by Q1. Once both stages have been activated, the controllers
are supplied also by the auxiliary winding of the resonant transformer, assuring correct
supply voltage during operation of all load conditions. The L1 auxiliary winding is also
connected to the L6562AT pin #5 (ZCD) through the resistor R18. Its purpose is to provide
the information that L1 has demagnetized, needed by the internal logic for triggering a new
switching cycle. The PFC boost peak current is sensed by resistors R33 and R34 in series
to the MOSFET source. The signal is fed into pin #4 (CS) of the L6562AT, via the filter R27
and C16.
The divider R7, R12, R14 and R22 provides the L6562AT multiplier with the information of
the instantaneous mains voltage that is used to modulate the peak current of the boost.
The resistors R2, R6, R9 with R15 and R16 are dedicated to sense the output voltage and
feed to the L6562AT the feedback information necessary to maintain the output voltage
regulated. The components C11, R20 and C12 constitute the error amplifier compensation
network necessary to keep the required loop stability.
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Main characteristics and circuit description
1.2
AN3106
Resonant power stage
The downstream converter is a resonant LLC half-bridge stage working with 50 percent
fixed duty cycle and variable frequency. It implements the ST L6599AT, integrating all
functions necessary to properly control the resonant topology.
The resonant transformer, manufactured by MAGNETICA, uses the integrated magnetic
approach, so the leakage inductance is used for resonant operation of the circuit. Thus, no
external, additional coil is needed for the resonance. The transformer secondary winding
configuration is the typical center tap, using a couple of power Schottky rectifiers type
STPS10150CG. The output capacitors are film type, 4.7 µF - 63 V from EPCOS. As for the
PFC stage, using film capacitors allows considerably increasing the MTBF of the board.
A small LC filter has been added on the output, in order to filter the high-frequency ripple.
D21, D22, R55 constitute a voltage-controlled bleeder. In case of no-load operation of the
SMPS, this circuit provides a bleeder limiting the output voltage from increasing, but not
affecting the efficiency during normal operation. Please note that the converter has not been
designed to work in this condition and therefore its mains consumption is not optimized (~3
W).
1.3
Startup sequence
The PFC acts as master and therefore starts first. The resonant stage operates only if the
PFC is delivering the nominal output voltage to prevent the resonant converter from working
with an insufficient input voltage that can cause incorrect capacitive mode operation. Thus,
both stages are designed to work according to this sequence.
For correct sequencing the L6599AT makes use of the LINE pin (#7) to sense the PFC
output voltage via a resistor divider. The L6599AT LINE pin (#7) has an internal comparator
which has a hysteresis allowing to set independently the turn-on and turn-off voltage. At
startup the LLC stage starts once the PFC output voltage reaches ~ 430 V, while the turn-off
threshold has been set to ~330 V.
1.4
Output voltage feedback loop
The output voltage is kept stable by means of a feedback loop implementing a typical circuit
using a TS2431 modulating the current in the optocoupler diode.
On the primary side, R43 - connecting pin RFMIN (#4) to the optocoupler's phototransistor allows modulating the L6599AT oscillator frequency, thus keeping the output voltage
regulated. It also sets the maximum switching frequency at about 130 kHz. R42, that
connects the same pin to ground, sets the minimum switching frequency. The R-C series
R37 and C24 sets both soft-start maximum frequency and duration.
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AN3106
Main characteristics and circuit description
All evaluation boards implement the voltage loop circuitry previously described but in case a
current loop is also required, it can be achieved by implementing the following modifications:
•
Replace R30 and R31 0R0 Ω resistors with sensing resistors, 0R033 and 0R039
respectively, both 0805
•
Populate on PCB U4 and the relevant components shown on the schematic as N.M:
C36 = 1N0-0805; C37 = 100NF-0805; R51 = 15R-0805; R56 = 1K0-0805;
R6 = 22K-1206; C41 = 2N2-0805; U5 = SEA05TR
•
Remove TS2431AILT
With these modifications the circuit is able to keep the output current constant at 2.7 A down
to an output voltage value around 30 V. This function can be used to optimize the voltage
drop and power dissipation in case current linear regulators are used to regulate the current
flowing in each LED strip. If the output current is lower, the voltage loop will take over the
operation, regulating the output voltage at its nominal value as when using the TS2431AILT.
1.5
Overload and short-circuit protection
The current flowing into the primary winding, proportional to the output load, is sensed by
the lossless circuit C34, R53, D19, D18, R57, and C35 and it is fed into the ISEN pin (#6) of
L6599AT. In case of overcurrent, the voltage on the pin will exceed an internal threshold (0.8
V), triggering a protection sequence. The capacitor (C21) connected to the DELAY pin (#2)
is charged by an internal 150 µA current generator. If the voltage on the pin reaches 2 V, the
soft-start capacitor is completely discharged so that the switching frequency is pushed to its
maximum value. As the voltage on the pin exceeds 3.5 V the IC stops switching and the
internal generator is turned off, so that the voltage on the DELAY pin will decay because of
the external resistor connected between the pin and GND. The L6599AT will be softrestarted as the voltage drops below 0.3 V. In this way, under short-circuit conditions, the
converter will work intermittently with low input average power and thus limiting the stress of
components during shorts.
1.6
Overvoltage and open loop protection
Both circuit stages, PFC and resonant, are equipped with their own overvoltage protections.
The PFC controller L6562AT implements an overvoltage protection against the output
voltage variation occurring in case of transients, due to the poor bandwidth of the error
amplifier. Unfortunately it cannot protect the circuit in case of a feedback loop failure like
disconnection or deviation from the nominal value of the feedback loop divider. If a similar
failure condition is detected, the L6599AT pin DIS (#8) stops the operation and also stops
the PFC operation by means of the L6599AT pin PFC_STOP (#9) connected to the
L6562AT pin INV (#1). The converter operation will be latched until the VCC capacitors are
discharged, then a new startup sequence will automatically take place and the converter will
resume operation if the failure is removed or a new sequence is triggered. The same
sequence occurs also in case of input voltage transients that may damage the converter.
The DIS pin is also used to protect the resonant stage against loop failures. The Zener
diode D17 detects the auxiliary voltage generated by the LLC transformer. In case a loop
failure occurs, it conducts and the voltage on pin DIS exceeds the internal threshold,
latching off the device. The L6562AT operation will be stopped too by the PFC_STOP pin,
like in the previous case and then after some time the circuit will restart.
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RX2
R47
VCC
1
R45
R14
R12
R7
2
D3
GBU8J
3
Q3
N. M. 2
VIN 1
C4
470 nF
R44
N. M.
ZCD
GND
GD
VCC
C31
220 nF
R42
R8
R5
R49
R37
220 nF
C9
10 nF
2
1
DELAY
CSS
HVG
VBOOT
L6599AT
U2
R33
R23
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RFMIN
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6
ISEN
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LINE
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6
7
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L6562AT
R16
R1
N.M. C24
MULT
CS
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4.7 nF
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1
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FUSE T4A
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7
6
14
13
10
11
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C27
220 nF
REV 0.7
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2
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470 nF
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N. M.
C39
R54
R60
R58
D15
BZV55-B24
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2
3
R41
C17 C18
1
R55
R51
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R29
N. M.
C41
N. M.
R61
N. M.
3
2
1
Vctrl
Ictrl
OUT
I.sense VCC
GND
1
2
C36
N. M.
C37
N. M.
AM00883
4
5
6
48 V at 2.7 A
100
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R30
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TS2431AILT
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C20
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9
2
8
C8
2.2 nF - Y1
C1
2.2 nF - Y1
Main characteristics and circuit description
AN3106
Figure 2. STEVAL-ILL053V1 evaluation board: electrical diagram
AN3106
2
Efficiency measurement
Efficiency measurement
Table 1 shows the overall efficiency, measured at 230 V - 50 Hz and 115 V - 60 Hz input
voltage and different loads.
At 115 VAC and full load the overall efficiency is 90.96%. It increases up to 93.38%
at 230 VAC, confirming that this reference design is suitable for high-efficiency power
supplies. The efficiency has been measured at 25%, 50%, 75% and 100%, and the average
efficiency according to the ES-2 standard has been calculated. As shown in Table 1 it is very
high at both nominal mains.
Table 1. STEVAL-ILL053V1 evaluation board: overall efficiency vs. load
230 V - 50 Hz
115 V - 60 Hz
Load
VOUT [V] IOUT [A] POUT [W] PIN [W]
Eff. [%] VOUT [V] IOUT [A] POUT [W] PIN [W] Eff. [%]
25% load
47.58
0.689
32.8
37.87
86.57%
47.59
0.689
32.8
37.87
86.58%
50% load
47.57
1.378
65.6
71.66
91.48%
47.58
1.378
65.6
72.93
89.90%
75% load
47.56
2.008
95.5
102.96
92.75%
47.56
2.001
95.2
105.0
90.64%
100% load
47.55
2.708
128.8
137.6
93.38%
47.56
2.703
128.6
141.33
90.96%
Average
efficiency
91.04%
89.52%
The measured output voltage at different load conditions is also shown in Table 1. As
visible, the voltage is very stable over the entire output load range.
The measured efficiency is shown in Figure 3, while Figure 4 shows the efficiency at
maximum load over the entire AC input voltage mains range.
Figure 4. STEVAL-ILL053V1 evaluation board:
full-load efficiency vs. VAC
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Figure 3. STEVAL-ILL053V1 evaluation board:
efficiency vs. load
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Input current harmonics measurement
3
AN3106
Input current harmonics measurement
One of the main purposes of a PFC precondition is the correction of input current distortion,
decreasing the harmonic contents below the limits of the relevant regulations. Therefore,
this evaluation board has been tested according to the European norm EN61000-3-2 ClassC and Japanese norm JEITA_MITI Class-C both relevant to lighting equipment, at full load
and nominal input voltage mains. The measurements are shown in Figure 5 and Figure 6.
Figure 5. STEVAL-ILL053V1 evaluation board:
compliance to EN61000-3-2 Class-C standard
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Figure 6. STEVAL-ILL053V1 evaluation board:
compliance to JEITA-MITI Class-C standard
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VIN = 230 VAC - 50 Hz,
PIN = 138.8 W
THD = 8.70%,
PF = 0.976
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VIN = 100 VAC - 50 Hz, PIN = 141.3 W
THD = 3.31%, PF = 0.994
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For user reference, waveforms of the input current and voltage at nominal input voltage
mains during full-load operation are shown in Figure 5 and Figure 6. Figure 7 and Figure 8
give the input current and voltage at nominal input voltage mains 50% load, showing that in
spite of the wide input voltage range, the current waveform shape is still good.
Figure 7. STEVAL-ILL053V1 evaluation board:
input current waveform at 230 V - 50 Hz - 65 W
load
Figure 8. STEVAL-ILL053V1 evaluation board:
input current waveform at 100 V - 50 Hz - 65 W
load
CH1: AC input mains voltage
CH1: AC input mains voltage
8/31
CH4: AC input mains current
DocID016775 Rev 3
CH4: AC input mains current
AN3106
Input current harmonics measurement
As confirmed by the previous graphs, the circuit also shows its ability to reduce the
harmonics well below the limits of EN61000-3-2 Class-C regulation not only at full load but
also at a significantly lower load. The input current harmonics measurement at 25 W
(minimum input power to be compliant with the previously mentioned rules is 25 W) shows
that even if the power supply is working from its typical operating region, it is still compliant
with the EN61000-3-2 Class-C limits. Test results are shown in Figure 9 and Figure 10.
Figure 9. STEVAL-ILL053V1 evaluation board:
compliance to EN61000-3-2 Class-C standard
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Figure 10. STEVAL-ILL053V1 evaluation board:
compliance to JEITA-MITI Class-C standard
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VIN = 230 VAC - 50 Hz, PIN = 25 W
THD = 11.80%, PF = 0.697
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VIN = 100 VAC - 50 Hz, PIN = 25 W
THD = 6.65%, PF = 0.92
The “Power Factor” (PF) and the “Total Harmonic Distortion” (THD) versus load variations
have been measured too and the results are shown in Figure 11 and Figure 12. As visible,
the Power Factor remains close to unity and the Total Harmonic Distortion is very low
throughout the input voltage mains.
Figure 11. STEVAL-ILL053V1 evaluation board: Figure 12. STEVAL-ILL053V1 evaluation board:
Power Factor vs. output power
Total Harmonic Distortion vs. output power
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Functional check
AN3106
4
Functional check
4.1
PFC circuit
In Figure 13 and Figure 15 some waveforms relevant to the PFC stage have been captured
during full load operation at nominal 230 VAC and 115 VAC. In both figures it is visible that
the envelope of the CS pin (#4) waveforms of the L6562AT is in phase with the MULT pin
(3#) and has same sinusoidal shape, demonstrating the proper functionality of the PFC
stage. It is also possible to measure the peak-to-peak value of the voltage ripple
superimposed on the PFC output voltage due to the low value of the PFC output capacitors.
In Figure 14 and Figure 16 the details of some waveforms at the switching frequency are
shown.
Figure 13. STEVAL-ILL053V1 evaluation board: Figure 14. STEVAL-ILL053V1 evaluation board:
PFC stage and L6562AT waveforms at 230 V - 50 PFC stage and L6562AT waveforms at 230 V - 50
Hz - full load
Hz - full load - detail
CH1: VOUT PFC
CH2: MULT
CH3: CS
CH1: VOUT PFC
CH2: MULT
CH3: CS
CH4: Vdrain_Q2
Figure 15. STEVAL-ILL053V1 evaluation board: Figure 16. STEVAL-ILL053V1 evaluation board:
PFC stage and L6562AT waveforms at 115 V - 60 PFC stage and L6562AT waveforms at 115 V - 60
Hz - full load
Hz - full load - detail
CH1: VOUT PFC
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CH2: MULT
CH3: CS
CH1: VOUT PFC
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CH2: MULT
CH3: CS
CH4: Vdrain_Q2
AN3106
4.2
Functional check
Half-bridge resonant LLC circuit
The following figures show waveforms relevant to the resonant stage during steady-state
operation. The resonant stage switching frequency is about 100 kHz, in order to have
a good trade-off between transformer losses and dimensions.
The LLC converter has been designed to operate at nominal voltage and full load at the
resonance frequency, but due to the PFC output voltage ripple at twice the mains frequency,
it is driven slightly above and below the resonant tank frequency, according to the
instantaneous value of the PFC output voltage.
In Figure 17 some waveforms relevant to the resonant stage ZVS operation are shown. We
note that both MOSFETs are turned on when resonant current is flowing through their body
diodes and drain-source voltage is almost zero, thus achieving good efficiency because the
turn-on losses are negligible. The HB MOSFET voltage de-rating and low operating
temperature allow increasing the board’s MTBF.
The current flowing in the resonant tank is sinusoidal. In Figure 17 we note a slight
asymmetry of operating modes by each half portion of the sine wave. The half cycle is
working at resonant frequency while the other one is working above the resonant frequency.
This is due to a small difference between each half-secondary leakage inductance of the
transformer reflected to the primary side, providing the two slightly different resonant
frequencies. This phenomenon is typically due to a different coupling of the transformer
secondary windings and, in this case, it is not an issue. The slight asymmetry is also visible
in Figure 18 where the small ringing appearing on both secondary rectifiers anode voltage
indicates that for a short time the rectifiers are not conducting. This demonstrates that
during the half cycle the circuit is working below the resonant frequency, while during the
following half cycle it is working at the resonant frequency.
In Figure 18 we also note the rectifier operating voltage and its margin with respect to the
maximum reverse voltage (VRRM). This de-rating with respect to the rectifiers VRRM
guarantees good reliability of the output rectifiers, increasing the board’s total MTBF.
Figure 17. STEVAL-ILL053V1 evaluation board: Figure 18. STEVAL-ILL053V1 evaluation board:
primary side LLC waveforms at 115 V - 60 Hz - secondary side LLC waveforms at 230 V- 50 Hz full load
full load
CH1: HB voltage
CH3: VCC
CH2: CF pin voltage
CH4: res. tank current
CH1: V_D12
CH3: VOUT
DocID016775 Rev 3
CH2: V_D12
11/31
31
Functional check
AN3106
In Figure 19 the high-frequency ripple has been measured. As visible the ripple and noise at
switching frequency is very limited, thanks to the low EMI generated by both stages. In
Figure 20 the low-frequency ripple has been measured too. We note that the peak-to-peak
value is not very low because of the low output capacitances but it doesn't affect the
application. In fact the converters regulating the current flowing in each LED strip can reject
the ripple without any problem.
Figure 19. STEVAL-ILL053V1 evaluation board: Figure 20. STEVAL-ILL053V1 evaluation board:
high frequency ripple on output voltage at 115 V low frequency ripple on output voltage at 115 V
- 60 Hz - full load
- 60 Hz - full load
CH3: VOUT
4.3
CH3: VOUT
Dynamic load operation
The waveforms shown in Figure 21 and Figure 22 pertain to the evaluation board during the
operation of supplying converters dedicated to power LED strips with constant current.
In both figures it is possible to see the output voltage modulation during operation with
variable load due to the dimming of the LED current by PWM. For both measurements, the
dimming frequency has been chosen at 300 Hz, a typical value for dimming.
In Figure 21 the converter’s output current was 2.6 A and the dimming duty cycle was 90%,
thus very close to the converter’s nominal output power. The output voltage has two
modulations. One is due to the rejection of the PFC output voltage ripple already measured
in Figure 20 where the voltage variation due to the LED current dimming is superimposed.
The peak-to-peak variation is 5.37 V but it doesn't present any problem for the load since
the converters reject the modulation.
In Figure 22 instead the converter has been checked at light load, so the peak output
current was 3 A and the dimming duty cycle was 15%, for an output power of 21 W. Even in
this case, the peak-to peak modulation doesn't present any issue for the downstream
current regulators and the board still works correctly.
12/31
DocID016775 Rev 3
AN3106
Functional check
Figure 21. STEVAL-ILL053V1 evaluation board: Figure 22. STEVAL-ILL053V1 evaluation board:
output voltage variation driving a CC LED
output voltage variation driving a CC LED
converter - PWM = 90%
converter - PWM = 15%
CH1: PWM dimming signal
CH4: SMPS output current
CH2: VOUT
CH1: PWM dimming signal
CH4: SMPS output current
CH2: VOUT
Please note that for correct operation with LED strips, the board needs additional capacitors
connected on the +48 V output bus. The board has not been equipped with all of the
capacitors necessary for correct operation with LEDs, but only with minimum capacitance to
allow board operation in order to optimize the system cost and reliability. The additional
capacitors needed are intended to be placed close to each LED strip current regulator, thus
filtering the EMI generated by these. In several cases, in fact, the power supply is placed at
the base of the lighting pole while the LED current regulators are located on top, in the lamp.
The long connection wiring between the power supply and the converters can act as an
antenna radiating EMI. Thus local filtering minimizes the radiated EMI.
The capacitance to be added to the 48 V bus for correct operation with LEDs is around
40 µF. In order to not affect the board MTBF, we suggest using the same type of capacitors
already used on the power supply board.
4.4
Overcurrent and overvoltage protection
The L6599AT is equipped with a current sensing input (pin #6, ISEN) and a dedicated
overcurrent management system. The current flowing in the resonant tank is detected and
the signal is fed into the ISEN pin. It is internally connected to a first comparator, referenced
to 0.8 V, and to a second comparator referenced to 1.5 V. If the voltage externally applied to
the pin exceeds 0.8 V, the first comparator is tripped, causing an internal switch to be turned
on and discharging the soft-start capacitor C24 (CSS).
Under output short-circuit, this operation results in a nearly constant peak primary current.
With the L6599AT the designer can program externally the maximum time that the converter
is allowed to run overloaded or under short-circuit conditions. Overloads or short-circuits
lasting less than the set time will not cause any other action, hence providing the system
with immunity to short duration phenomena. If, instead, the overload condition persists,
a protection procedure is activated that shuts down the L6599AT. In case of continuous
overload or short-circuit, it will result in continuous intermittent operation with a user-defined
duty cycle.
DocID016775 Rev 3
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31
Functional check
AN3106
This function is implemented with the DELAY pin (#2), by means of a capacitor C21 and the
parallel resistor R32 connected to ground. As the voltage on the ISEN pin exceeds 0.8 V,
the first OCP comparator, in addition to discharging CSS, turns on an internal 150 µA
current generator that via the DELAY pin charges C21. As the voltage on C21 is 3.5 V, the
L6599AT stops switching and the PFC_STOP pin (#9) is pulled low, turning off also the PFC
stage via the L6562AT pin#1 (INV). The internal generator is also turned off, so that C21 will
now be slowly discharged by R32. The IC will restart once the voltage on C21 is less than
0.3 V. Additionally, if the voltage on the ISEN pin reaches 1.5 V for any reason (e.g.
transformer saturation), the second comparator will be triggered, the L6599AT will shut
down and the operation will be resumed after recycling of the VCC. In this evaluation board
the intervention of the second level comparator will latch the operation of the L6599AT and
the PFC_STOP pin (#9) will stop the PFC. Both controllers will no longer be powered by
VCC and the latch will be removed and then a new startup cycle will take place. This
sequence continues until the short is removed.
Figure 23 shows the operation of the DELAY pin and the consequent hiccup mode
operation of the board during short-circuit operation. Thanks to the narrow operating time
with respect to the off-time, the average output current as well as the average primary
current are limited. This will avoid converter overheating and consequent failures. Removing
the short allows the board to resume normal operation.
Figure 23. STEVAL-ILL053V1 evaluation board: Figure 24. STEVAL-ILL053V1 evaluation board:
short-circuit at 115 VAC - 60 Hz - full load
open loop at 115 VAC - 60 Hz - 65 W load
CH1: V_OUT_PFC
CH3: DELAY pin
CH2: HB voltage
CH4: U1 pin INV
CH1: Q1_Drain
CH3: VOUT
CH2: HB voltage
CH4: DIS pin
Figure 24 shows the operation of the evaluation board during “open loop” operation by the
LLC stage. The open loop operation provides an increase also of the auxiliary voltage that
will trigger the L6599AT pin #9 (DIS) protection pin via the Zener diode D17. As
a consequence, the L6599AT will shut down, stopping the operation. The L6599AT will
activate also the PFC_STOP pin (#9) that will stop the PFC too, thus both controllers will no
longer be powered by VCC. Once VCC drops below the UVLO, the latch is removed and then
a new startup cycle will take place. This sequence continues until the open loop is removed.
4.5
Converter startup
Figure 25 and Figure 27 show the converter startup. We note that at 115 VAC the converter
begins operation in ~300 ms, while at 230 VAC it takes around 150 ms. This is the time
14/31
DocID016775 Rev 3
AN3106
Functional check
needed to charge the VCC to the L6562AT turn-on voltage. Thus the L6562AT starts
switching and the PFC output voltage starts increasing. Once the PFC output voltage
reaches the enable level set via the L6599AT LINE pin, even the LLC stage starts switching
and the output voltage rises up to the nominal level. The VCC is initially supplied by the PFC
coil charge pump, and then once the L6599AT starts operating, the VCC is also provided by
the LLC transformer auxiliary winding. The details of converter sequencing can be found in
Figure 26 and Figure 28.
Figure 25. STEVAL-ILL053V1 evaluation board: Figure 26. STEVAL-ILL053V1 evaluation board:
wake-up at 115 VAC - 60 Hz - full load
sequencing at 115 VAC - 60 Hz - full load
CH1: Q2_Drain
CH3: L6562AT VCC
CH2: HB voltage
CH4: VOUT
CH1: Q2_Drain
CH3: L6599AT VCC pin
CH2: HB voltage
CH4: VOUT
Figure 27. STEVAL-ILL053V1 evaluation board: Figure 28. STEVAL-ILL053V1 evaluation board:
wake-up at 230 VAC - 50 Hz - full load
sequencing at 230 VAC - 60 Hz - full load
CH1: Q2_Drain
CH3: L6562AT VCC
CH2: HB voltage
CH4: VOUT
CH1: Q2_Drain
CH3: L6599AT VCC pin
CH2: HB voltage
CH4: VOUT
Figure 25 through 28 show a correct startup of the board using an active load, with only the
capacitors for the 48 V populating the board. Powering current regulators with LEDs may
cause the board to show an incorrect startup, with output voltage going up and down and
LEDs flashing. As already explained in Section 4.3, the board needs an additional 40 µF
capacitance on the +48 V.
DocID016775 Rev 3
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31
Thermal map
5
AN3106
Thermal map
In order to check the design reliability, a thermal mapping by means of an IR camera was
done. Here below the thermal measures of the board, component side, at nominal input
voltage are shown. Some pointers visible on the pictures have been placed across key
components or components showing high temperature. The ambient temperature during
both measurements was 27 °C. We note that the PFC part has a different temperature
depending on the input mains, while the components of the resonant stage are working at
a temperature independent of the mains input voltage.
Figure 29. Thermal map at 115 VAC - 60 Hz - full load - PCB top side
Figure 30. Thermal map at 230 VAC - 50 Hz - full load - PCB top side
Table 2. Thermal maps reference points - PCB top side
16/31
Point
Reference
Description
A
L2
EMI filtering inductor
B
D3
Bridge rectifier
C
Q2
PFC MOSFET
D
L1
PFC inductor
E
T1
Resonant power transformer - winding
F
T1
Resonant power transformer - ferrite core
DocID016775 Rev 3
AN3106
Thermal map
Figure 31. Thermal map at 115 VAC - 60 Hz - full load - PCB bottom side
Figure 32. Thermal map at 230 VAC - 50 Hz - full load - PCB bottom side
Table 3. Thermal maps reference points - PCB bottom side
Point
Reference
Description
A
Q4
LLC resonant HB MOSFET
B
Q5
LLC resonant HB MOSFET
C
D2
PFC output diode
D
R33 and R34
PFC sense resistors
E
Q1
VCC voltage regulator
F
D12
Output rectifier
G
D11
Output rectifier
DocID016775 Rev 3
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31
Conducted emission precompliance measurement
6
AN3106
Conducted emission precompliance measurement
Figure 33 to Figure 36 show the average measurement of the conducted noise at full load
and nominal mains voltages for both wires, line and neutral. The limits on the diagrams are
the EN55022 Class-B norms. As visible on the diagrams, in all test conditions the
measurements are well below the limits.
Figure 33. CE average measurement at 115 VAC and full load - phase wire
Figure 34. CE average measurement at 115 VAC and full load - neutral wire
18/31
DocID016775 Rev 3
AN3106
Conducted emission precompliance measurement
Figure 35. CE average measurement at 230 VAC and full load - phase wire
Figure 36. CE average measurement at 230 VAC and full load - neutral wire
DocID016775 Rev 3
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31
Bill of material
7
AN3106
Bill of material
Table 4. STEVAL-ILL053V1 evaluation board: bill of material
Des.
Part type / part
value
Case style
/ package
Description
Supplier
C1
2.2 nF - Y1
4.5 x 12.0
p.10 mm
Y1 safety cap. DE1E3KX222M
Murata
C10
1 µF
1206
50 V CERCAP - general purpose - X7R- 10%
TDK©
C11
470 nF
0805
16 V CERCAP - general purpose - X7R - 10%
Murata
C12
2.2 µF
0805
10 V CERCAP - general purpose
AVX
C13
10 µF
1210
25 V-X7R CERCAP - gen. purpose - X7R - 20%
TDK
C15
4.7 nF
0805
50 V CERCAP - general purpose - X7R - 10%
KEMET
C16
220 pF
0805
50 V CERCAP - general purpose - C0G - 5%
KEMET
C17
4.7 µF
7.8 x 7.8
p. 5
63 V - MKT film cap. - B32529D0475M000
EPCOS
C18
4.7 µF
7.8 x 7.8
p. 5
63 V - MKT film cap. - B32529D0475M000
EPCOS
C19
100 nF
0805
100 V CERCAP - general purpose - X7R - 10%
AVX
C2
470 nF - X2
9 × 18.0
p.15 mm
X2 - MKP film cap. - B32922C3474K
EPCOS
C20
15 nF
5 x 18
p.15 mm
1000 V - MKP film cap. - B32652A0153K000
EPCOS
C21
220 nF
0805
16 V CERCAP - general purpose - X7R - 10%
Murata
C22
100 nF
1206
50 V CERCAP - general purpose - X7R - 10%
KEMET
C24
4.7 µF
0805
6.3 V CERCAP - general purpose - X5R - 10%
EPCOS
C25
470 pF
0805
50 V CERCAP - general purpose - COG - 5%
EPCOS
C26
4.7 nF
0805
50 V CERCAP - general purpose - X7R - 10%
KEMET
C27
220 nF
0805
50 V CERCAP - general purpose - X7R - 10%
Murata
C3
470 nF - X2
9 × 18.0
p.15 mm
X2 - MKP film cap. - B32922C3474K
EPCOS
C30
10 µF
1210
25 V CERCAP - general purpose - X7R - 20%
TDK
C31
220 nF
0805
16 V CERCAP - general purpose - X7R - 10%
Murata
C32
220 nF
0805
16 V CERCAP - general purpose - X7R - 10%
Murata
C33
10 nF
0805
50 V CERCAP - general purpose - X7R - 10%
KEMET
C34
220 pF
1206
1 KV high voltage CERCAP - X7R - 10%
AVX
C35
220 nF
0805
16 V CERCAP - general purpose - X7R - 10%
Murata
C36
N. M.
0805
Not mounted
C37
N. M.
0805
Not mounted
C38
N. M.
0805
Not mounted
20/31
DocID016775 Rev 3
AN3106
Bill of material
Table 4. STEVAL-ILL053V1 evaluation board: bill of material (continued)
Des.
Part type / part
value
Case style
/ package
Description
Supplier
C39
470 nF
0805
25 V CERCAP - general purpose - X7R - 10%
KEMET
C4
470 nF
9 × 18.0
p.15 mm
X2 - MKP film cap. -B32922C3474K
EPCOS
C40
10 µF
2220
50 V - CERCAP - general purpose - X7R - 20%
TDK
C41
N. M.
0805
Not mounted
C5
5 µF
14 × 31.5
p. 27.5 mm
800 V - MKP film cap. - B32774D8505K000
EPCOS
C6
5 µF
14 × 31.5
p. 27.5 mm
800 V - MKP film cap. - B32774D8505K000
EPCOS
C7
5 µF
14 × 31.5
p. 27.5mm
800 V - MKP film cap. - B32774D8505K000
EPCOS
C8
2.2 nF - Y1
4.5 x 12
p.10 mm
Y1 safety cap. DE1E3KX222M
Murata
C9
10 nF
1206
100 V CERCAP - gen. purpose - X7R - 10%
KEMET
D1
1.4007 nF
DO-41
General purpose rectifier
VISHAY®
D10
N. M.
SOD-80
Zener diode
D11
STPS10150CG
D2PAK
Power Schottky rectifier
STMicroelectronics
D12
STPS10150CG
D2PAK
Power Schottky rectifier
STMicroelectronics
D13
LL4148
SOD-80
Fast switching diode
VISHAY
D14
LL4148
SOD-80
Fast switching diode
VISHAY
D15
BZV55-B24
SOD-80
Zener diode
VISHAY
D16
LL4148
SOD-80
Fast switching diode
VISHAY
D17
BZV55-B24
SOD-80
Zener diode
VISHAY
D18
LL4148
SOD-80
Fast switching diode
VISHAY
D19
LL4148
SOD-80
Fast switching diode
VISHAY
D2
STTH3L06U
SMB
Ultrafast high voltage rectifier
STMicroelectronics
D20
STPS1L60A
SMA
Fast switching diode
STMicroelectronics
D21
BZV55-B24
SOD-80
Zener diode
VISHAY
D22
BZV55-B24
SOD-80
Zener diode
VISHAY
JPX9
/D23
Jumper
D24
LL4149
SOD-81
Fast switching diode
VISHAY
D3
GBU8J
STYLE
GBU DWG
Single phase bridge rectifier
VISHAY
D4
LL4148
SOD-80
Fast switching diode
VISHAY
D5
LL4148
SOD-80
Fast switching diode
VISHAY
Wire jumper
DocID016775 Rev 3
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31
Bill of material
AN3106
Table 4. STEVAL-ILL053V1 evaluation board: bill of material (continued)
Des.
Part type / part
value
Case style
/ package
Description
Supplier
D6
LL4148
SOD-80
Fast switching diode
VISHAY
D7
BZV55-B15
SOD-80
Zener diode
VISHAY
D8
LL4148
SOD-80
Fast switching diode
VISHAY
D9
LL4148
SOD-80
Fast switching diode
VISHAY
F1
FUSE T4A
8.5 x 4
p. 5.08 mm
Fuse 4 A - time lag - 3921400
LITTLEFUSE
HS1
Heatsink
DWG
Heatsink for D3 and Q2
J1
MKDS 1,5 / 3-5,08 p. 5.08 mm
PCB term. block, screw conn., pitch 5 MM - 3 W.
PHOENIX CONTACT
J2
MKDS 1,5 / 2-5,08 p. 5.08 mm
PCB term. block, screw conn., pitch 5 MM - 2 W.
PHOENIX CONTACT
L1
1975.0001
DWG
PFC choke - 520 µH PQ26/25
MAGNETICA
L2
12 mH
DWG
CM filter 2019.0002
MAGNETICA
L3
3.3 µH - 4.7 A
DIA. 7.7 p.
5 mm
Inductor 1071.0080
MAGNETICA
Q1
BC846C
SOT-23
NPN small signal BJT
VISHAY
Q2
STF22NM60N
TO220
N-channel Power MOSFET
STMicroelectronics
Q3
N. M.
SOT-23
PNP small signal BJT
Q4
STD10NM60N
DPAK
N-channel Power MOSFET
STMicroelectronics
Q5
STD10NM60N
DPAK
N-channel Power MOSFET
STMicroelectronics
Q6
BC846C
SOT-23
NPN small signal BJT
VISHAY
Q7
BC846C
SOT-23
NPN small signal BJT
VISHAY
Q8
BC846C
SOT-23
NPN small signal BJT
VISHAY
R1
N. M.
0805
Not mounted
R10
1.2 MΩ
1206
SMD standard film res. - 1/4 W - 1% - 100 ppm / °C
VISHAY
R11
4.7 KΩ
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
R12
2.0 MΩ
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
R13
120 KΩ
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
R14
390 KΩ
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
R15
39 KΩ
0805
SMD standard film res. - 1/8 W - 1% - 100 ppm / °C
VISHAY
R16
39 KΩ
0805
SMD standard film res. - 1/8 W - 1% - 100 ppm / °C
VISHAY
R17
0Ω
1206
SMD standard film res. - 1/4 W - 1% - 100 ppm / °C
VISHAY
R18
56 KΩ
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
R19
0Ω
0805
SMD standard film res. - 1/8 W - 1% - 100 ppm / °C
VISHAY
R2
1 MΩ
1206
SMD standard film res. - 1/4 W - 1% - 100 ppm / °C
VISHAY
R20
120 KΩ
0805
SMD standard film res. - 1/8 W - 5% - 250 ppm / °C
VISHAY
R21
33 Ω
0805
SMD standard film res. - 1/8 W - 5% - 250 ppm / °C
VISHAY
22/31
DocID016775 Rev 3
AN3106
Bill of material
Table 4. STEVAL-ILL053V1 evaluation board: bill of material (continued)
Des.
Part type / part
value
Case style
/ package
Description
Supplier
R22
39 KΩ
0805
SMD standard film res. - 1/8 W - 5% - 250 ppm / °C
VISHAY
R23
100 Ω
0805
SMD standard film res. - 1/8 W - 5% - 250 ppm / °C
VISHAY
R24
1.4 MΩ
1206
SMD standard film res.- 1/4 W - 1% - 100 ppm / °C
VISHAY
R25
82 KΩ
0805
SMD standard film res.- 1/8 W - 1% - 100 ppm / °C
VISHAY
R26
15 KΩ
0805
SMD standard film res. - 1/8 W - 1% - 100 ppm / °C
VISHAY
R27
470 Ω
0805
SMD standard film res. - 1/8 W - 5% - 250 ppm / °C
VISHAY
R29
N. M.
1206
Not mounted
R3
10 Ω
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
R30
0Ω
1206
SMD standard film res.- 1/8 W - 1% - 100 ppm / °C
VISHAY
R31
0Ω
1206
SMD standard film res. - 1/8 W - 1% - 100 ppm/ °C
VISHAY
R32
270 KΩ
0805
SMD standard film res.- 1/8 W - 5% - 250 ppm / °C
VISHAY
R33
0.39 Ω
2010
SMD standard film res. - 1/2 W - 5% - 250 ppm / °C
VISHAY
R34
0.39 Ω
2010
SMD standard film res. - 1/2 W - 5% - 250 ppm / °C
VISHAY
R36
4.7 KΩ
0805
SMD standard film res. - 1/8 W - 5% - 250 ppm / °C
VISHAY
R37
6.8 KΩ
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
R38
2.2 MΩ
0805
SMD standard film res. - 1/8 W - 5% - 250 ppm / °C
VISHAY
R39
51 Ω
0805
SMD standard film res. - 1/8 W - 5% - 250 ppm / °C
VISHAY
R4
1.2 MΩ
1206
SMD standard film res. - 1/4 W - 1% - 100 ppm / °C
VISHAY
R41
4.7 KΩ
1206
SMD standard film res.- 1/4 W - 5% - 250 ppm / °C
VISHAY
R42
10 KΩ
0805
SMD standard film res. - 1/8 W - 1% - 100 ppm / °C
VISHAY
R43
10 KΩ
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
R44
N. M.
0805
SMD standard film res. - 1/8 W - 5% - 250 ppm / °C
R45
220 KΩ
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
R46
51 Ω
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
R47
220 KΩ
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
R49
0Ω
0805
SMD standard film res. - 1/8 W - 5% - 250 ppm / °C
VISHAY
R5
120 KΩ
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
R50
10 KΩ
0805
SMD standard film res. - 1/8 W - 5% - 250 ppm / °C
VISHAY
R51
N. M.
0805
Not mounted
R52
10 Ω
0805
SMD standard film res. - 1/8 W - 5% - 250 ppm / °C
VISHAY
R53
100 RΩ
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
R54
2.2 KΩ
0805
SMD standard film res. - 1/8 W - 5% - 250 ppm / °C
VISHAY
R55
470 Ω
0805
SMD standard film res. - 1/8 W - 5% - 250 ppm / °C
VISHAY
R56
N. M.
0805
Not mounted
DocID016775 Rev 3
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31
Bill of material
AN3106
Table 4. STEVAL-ILL053V1 evaluation board: bill of material (continued)
Des.
Part type / part
value
Case style
/ package
Description
Supplier
R57
100 Ω
0805
SMD standard film res.- 1/8 W - 5% - 250 ppm / °C
VISHAY
R58
150 KΩ
0805
SMD standard film res. - 1/8 W - 1% - 100 ppm / °C
VISHAY
R59
1.5 Ω
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
R6
1.0 MΩ
1206
SMD standard film res.- 1/4 W - 1% - 100 ppm / °C
VISHAY
R60
8.2 KΩ
0805
SMD standard film res.- 1/8 W - 1% - 100 ppm / °C
VISHAY
R61
N. M.
1206
Not mounted
R62
100 KΩ
0805
SMD standard film res. - 1/8 W - 5% - 250 ppm / °C
VISHAY
R7
2.0 MΩ
1206
SMD standard film res. - 1/4W - 5% - 250 ppm/ °C
VISHAY
R8
120 KΩ
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
R9
1.5 MΩ
1206
SMD standard film res. - 1/4 W - 1% - 100 ppm / °C
VISHAY
RV1
300 VAC
dia. 15 x 5
p. 7.5 mm
300 V metal oxide varistor - B72214S0301K101
EPCOS
RX1
0Ω
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
RX2
0Ω
1206
SMD standard film res. - 1/4 W - 5% - 250 ppm / °C
VISHAY
T1
1860.0013
DWG ETD34
Resonant power transformer
MAGNETICA
U1
L6562ATD
SO-8
TM PFC controller
STMicroelectronics
U2
L6599ATD
SO-16
Improved HV resonant controller
STMicroelectronics
U3
SFH617A-2X009
SMD4 10.16 mm
Optocoupler
VISHAY
U4
SEA05 - N. M.
SOT-23-6L
CC/CV controller – not mounted
STMicroelectronics
U5
TS2431AILT
SOT-23
Programmable shunt voltage reference
STMicroelectronics
Z1
PCB rev. 0.2
24/31
DocID016775 Rev 3
AN3106
8
PFC coil specifications
PFC coil specifications
General description and characteristics
•
Application type: consumer, home appliance
•
Transformer type: open
•
Coil former: vertical type, 6 + 6 pins
•
Max. temp. rise: 45 °C
•
Max. operating ambient temperature: 60 °C
•
Mains insulation: N. A.
•
Unit finishing: varnished
Electrical characteristics
•
Converter topology: boost, transition mode
•
Core type: PQ26/25-PC44 or equivalent
•
Min. operating frequency: 30 kHz
•
Typical operating frequency: 120 kHz
•
Primary inductance: 0.52 mH ± 10% at 1 kHz - 0.25 V, measured between pins #5
and #9
•
Peak primary current: 4.3 Apk
•
RMS primary current: 1.8 ARMS
Electrical diagram and winding characteristics
Figure 37. PFC coil electrical diagram
$0
DocID016775 Rev 3
25/31
31
PFC coil specifications
AN3106
Table 5. PFC coil winding data
Pins
Windings
Number of turns
Wire type
11 - 3
Aux.
6
0.28 mm - G2
5-9
Primary
62
Multistrand #7x 0.28 mm - G2
•
Primary winding external insulation: 2 layers of polyester tape
•
Aux. winding is wound on top of primary winding
•
External insulation: 2 layers of polyester tape
•
Wire connected to pin 5 is insulated by sleeve
Mechanical aspect and pin numbering
26/31
•
Maximum height from PCB: 29 mm
•
Coil former type: vertical, 6 + 6 pins (pins #1, 2, 4, 6, 7, 10, 12 are removed)
•
Pin distance: 3.81 mm
•
Row distance: 25 mm
•
Coil former P/N: TDK BPQ26/25-1112CP
•
External copper shield: not insulated, wound around the ferrite core and including the
coil former. Height is 8 mm. Connected to pin #3 by a soldered solid wire.
DocID016775 Rev 3
AN3106
PFC coil specifications
Figure 38. PFC coil mechanical aspect
PD[
PD[
PD[
%RWWRPYLHZSLQVLGH
$0
1. Quotes are in millimeters, drawing is not to scale.
Manufacturer
•
MAGNETICA di R. Volpini - Italy (www.magneticait.it)
•
Inductor P/N: 1975.0001.
DocID016775 Rev 3
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31
Transformer specifications
9
AN3106
Transformer specifications
General description and characteristics
•
Application type: consumer, home appliance
•
Transformer type: open
•
Coil former: horizontal type, 7 + 7 pins, two slots
•
Max. temp. rise: 45 °C
•
Max. operating ambient temperature: 60 °C
•
Mains insulation: acc. with EN60950
Electrical characteristics
•
Converter topology: half-bridge, resonant
•
Core type: ETD34-PC44 or equivalent
•
Min. operating frequency: 70 kHz
•
Typical operating frequency: 100 kHz
•
Primary inductance: 770 µH ± 15% at 1 kHz - 0.25 V(a)
•
Leakage inductance: 170 µH at 100 kHz - 0.25 V(b)
Electrical diagram and winding characteristics
Figure 39. Transformer electrical diagram
35,0
$8;
6(&$
6(&%
$0
Table 6. Transformer winding data
Pins
Winding
RMS current
Number of turns
Wire type
2-4
Primary
1 ARMS
47
#30 x 0.1 mm - G2
8-10
Sec. - A(1)
0.05 ARMS
9
#60 x 0.1 mm - G2
12-14
B4(1)
2.2 ARMS
9
#60 x 0.1 mm - G2
2.2 ARMS
3
0.28 mm - G2
6-7
Sec. -
Aux.(2)
1. Secondary windings A and B have to be wound in parallel.
2. Aux. winding is wound on top of primary winding, turns are close each other, placed on external side of the
coil former.
a. Measured between pins 2-4.
b. Measured between pins 2-4 with only one secondary winding shorted. Difference between the two measured
leakage inductances has to be < 10%.
28/31
DocID016775 Rev 3
AN3106
Transformer specifications
Mechanical aspect and pin numbering
•
Maximum height from PCB: 30 mm
•
Coil former type: horizontal, 7 + 7 pins (pins #1, #3 and #5 removed for PCB reference)
•
Pin distance: 5.08 mm
•
Row distance: 25.4 mm
Figure 40. Transformer mechanical aspect
PD[
PD[
PLQ
PD[
/$%(/
0LVVLQJ3,1DQG
DV3&%UHIHUHQFH
3,1VLGHYLHZ
$0
1. Quotes are in millimeters, drawing is not to scale.
Manufacturer
•
MAGNETICA di R. Volpini - Italy (www.magneticait.it)
•
Transformer P/N: 1860.0013.
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31
Revision history
10
AN3106
Revision history
Table 7. Document revision history
30/31
Date
Revision
Changes
01-Sep-2010
1
Initial release.
28-Sep-2012
2
– Modified: Figure 2
– Modified: Table 4
– Minor text changes to improve readability
13-May-2016
3
– Updated: Figure 1 on the cover page
DocID016775 Rev 3
AN3106
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