AN3407
Application note
Resonant driver for LED SMPS demonstration board
based on the L6585DE
Introduction
This application note describes the performance of a 100 W LED switched-mode power
supply (SMPS). The L6585DE embeds a high-performance transition mode (TM) power
factor correction (PFC) controller, half-bridge (HB) controller and all the relevant drivers
necessary to build a combo IC. The L6585DE embeds a wide range of features to provide
an energy-saving and cost-effective solution for the LED SMPS demonstration board
(STEVAL-ILL038V1).
Previous dedicated ICs for LED SMPS applications allowed designers to achieve good
driver efficiency. The PFC section has superior performance in terms of harmonic content
mitigation. High power factor (PF) and total harmonic distortion (THD) reduction are
obtained as required by international norms, especially concerning universal input voltage
operations. The TM PFC operation and high-efficiency performance of the half-bridge
topology provide very good overall circuit efficiency.
Film capacitors are one of the most popular types of discrete components. They generally
offer excellent electrical properties and are advantageous in high current and high
temperature conditions. For these reasons, film capacitors are used in LED SMPS
applications. In order to guarantee maintenance-free operation required by these types of
applications during the useful lifetime of the LED, electrolytic capacitors have been replaced
by film capacitors in the STEVAL-ILL038V1 board.
Other features, such as half-bridge overcurrent with frequency increase and PFC
overvoltage, allow designers to build a reliable, flexible solution with a reduced component
count.
Figure 1. STEVAL-ILL038V1 demonstration board
August 2011 Doc ID 018857 Rev 1 1/25
www.st.com
Contents AN3407
Contents
1 L6585DE combo IC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 Main characteristics and circuit description . . . . . . . . . . . . . . . . . . . . . 5
2.1 VCC section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Power factor corrector section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.3 Resonant power section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.4 Output voltage feedback loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3 Efficiency measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4 Input current harmonics measurement . . . . . . . . . . . . . . . . . . . . . . . . . 11
5 Functional check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1 PFC circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.2 Half-bridge resonant LLC circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.3 Converter startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6 Bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
7 EMI choke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
8 PFC coil specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
9 Transformer specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
10 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
11 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2/25 Doc ID 018857 Rev 1
AN3407 List of figures
List of figures
Figure 1. STEVAL-ILL038V1 demonstration board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Figure 2. Application example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 3. Multiplier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 4. Oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 5. Half-bridge protection thresholds during run mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 6. Electrical schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 7. STEVAL-ILL038V1 demonstration board: efficiency vs. load . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 8. STEVAL-ILL038V1 demonstration board: full-load efficiency vs. VAC . . . . . . . . . . . . . . . . 10
Figure 9. STEVAL-ILL038V1 demonstration board: power factor vs. load . . . . . . . . . . . . . . . . . . . . 10
Figure 10. EN61000-3-2 Class-D standard - 185 VAC/50 Hz, THD=4.86%, PF=0.993 at full load. . . 11
Figure 11. EN61000-3-2 Class-D standard - 230 VAC/50 Hz, THD=5.98%, PF=0.980 at full load. . . 11
Figure 12. Input current waveforms - full load at 115 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 13. Input current waveforms - full load at 230 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 14. PFC stage waveforms at 115 VAC - full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 15. PFC stage waveforms at 230 VAC - full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 16. PFC stage waveforms at 115 VAC - full load - detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 17. PFC stage waveforms at 230 VAC - full load - detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 18. Primary side LLC waveforms at 115 VAC - full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 19. Secondary side LLC waveforms at 230 VAC - full load . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 20. High-frequency ripple on output voltage at 115 VAC - 60 Hz - full load . . . . . . . . . . . . . . . 15
Figure 21. Low-frequency ripple on output voltage at 115 VAC - 60 Hz - full load . . . . . . . . . . . . . . . 15
Figure 22. Wake-up at 115 VAC - 60 Hz - full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 23. Wake-up at 230 VAC - 60 Hz - full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 24. PCB: topside and through-hole components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 25. PCB: bottomside and SMD components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 26. PCB: topside placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 27. PCB: bottomside placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 28. EMI: OTC21V-4S vertical type EMI choke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 29. PFC: QP2520V-vertical type for PFC choke. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 30. Transformer: LP2920H - horizontal type for LLC transformer. . . . . . . . . . . . . . . . . . . . . . . 22
Doc ID 018857 Rev 1 3/25
L6585DE combo IC AN3407
1 L6585DE combo IC
The L6585DE embeds both a PFC converter and a half-bridge resonant in a single SO20
package.
● Transition mode PFC converter with overvoltage and overcurrent protection
● Half-bridge controller with high-voltage driver (600 Vdc) and integrated bootstrap diode
● 3% precise, fully programmable oscillator
● Overcurrent protection
● Hard-switching detection
Figure 2. Application example
4/25 Doc ID 018857 Rev 1
AN3407 Main characteristics and circuit description
2 Main characteristics and circuit description
The main features of the SMPS are listed here below:
● Extended input mains range: 90 ~ 265 V
● Output voltage: 48 V at 2.08 A
● Long-life, electrolytic capacitors are not used
● Mains harmonics: according to EN61000-3-2 Class-D
● Efficiency at full load: better than 90%
● Dimensions: 75 x 135 mm
2.1 VCC section
The L6585DE is supplied by applying voltage between the VCC pin and GND pin. An
undervoltage lockout (UVLO) prevents the IC from operating with supply voltages too low to
guarantee the correct behavior of the internal structures.
An internal voltage clamp limits the voltage to around 17 V and a delivery up to 20 mA. For
this reason it cannot be used directly as a clamp for the charge pump (current peaks usually
reach several hundreds of mA), but can be easily used during startup in order to charge the
VCC capacitor or during save mode in order to keep the IC alive, for example, connecting
VCC to input voltage through a resistor.
- frequency 50/60 Hz
AC
The L6585DE is supplied by the startup MOSFET Q4 and R40 charging the capacitor C25.
A charge pump connected to the auxiliary winding of the HB inductor T2 supplies the
controller via a small linear regulator represented by Q7. Once both stages have been
activated, the controllers are supplied also by the auxiliary winding of the resonant
transformer, assuring correct supply voltage during all load conditions. As the voltage on the
VCC pin reaches the turn-on threshold, the chip is enabled, and the half-bridge and the PFC
sections start at the same time.
2.2 Power factor corrector section
The PFC output voltage is controlled by means of a voltage-mode error amplifier and a
precise internal voltage reference. The PFC section achieves current mode control
operating in transition mode, offering a highly linear multiplier including a THD optimizer that
allows for an extremely low THD, even over a large range of input voltages and loading
conditions.
The controller is the L6585DE (U1), working in transition mode and integrating all functions
that are needed to perform the PFC. It delivers a stable 450 Vdc. It is a conventional boost
converter connected to the output of the rectifier bridge. It includes the coil T1, the PFC
transformer by YuJing, the diode D2 (STTH3L06U) and the PFC output capacitors C2, C3
and C4 by film type of 5 µF/800 V. The T1 provides also the information about the PFC coil
core demagnetization to pin#11 (ZCD) of the L6585DE. The T1 auxiliary winding is
connected to pin#11 (ZCD) of the L6585DE through the resistor R10. Its purpose is to
provide the information that T1 has demagnetized which is needed by the internal logic for
triggering a new switching cycle. The boost switch is represented by the power MOSFET
Q2. The T1 secondary winding (pins#8-6) and related circuitry are dedicated to power the
L6585DE during normal operation.
Doc ID 018857 Rev 1 5/25
Main characteristics and circuit description AN3407
The divider R6, R9, R14 and R16 provides to the L6585DE multiplier the information of the
instantaneous mains voltage that is used to modulate the peak current of the boost. In
Figure 3 the characteristic curves of the multiplier are given. The resistors R1, R3, R7 with
R11 and C31 are dedicated to sense the output voltage and feed to the L6585DE the
feedback information necessary to maintain the output voltage regulated. The components
C7, R13 and C8 constitute the error amplifier compensation network necessary to keep the
required loop stability.
The resistors R2, R4, R5 with R8 are dedicated to detecting two different overvoltage
protections: dynamic overvoltage usually due to fast load transition, and static overvoltage
due to an excessive input voltage. The PFC boost peak current is sensed by resistors R23 in
series to the MOSFET source. The signal is fed into pin#12 (PFCS) of the L6585DE. The
protection is not latched, once the PFCCS falls below 1.7 V, the PFC driver restarts.
Figure 3. Multiplier
2.3 Resonant power section
The resonant converter half-bridge topology works in ZVS. The resonant transformer T2,
manufactured by YuJing, uses the integrated magnetic approach. The leakage inductance is
used for resonant operation of the circuit. The T2 doesn't need an external coil for the
resonance. The T2 secondary winding configuration is the typical center tap, using a couple
of type D5 and D7 power Schottky rectifiers. The output capacitors are film type C15 and
C16 (4.7 µF/63 V). L2 and C17 filters have been added on the output, in order to filter the
high-frequency ripple.
The half-bridge driver oscillation is regulated by a current-controlled oscillator. It needs a
capacitor connected to pin#1 (OSC) of the L6585DE and uses the current flowing outside
pin#2 (RF) of the L6585DE as reference. Pin#2 (RF) of the L6585DE has a 2 V precise
voltage reference that lets the designer fix the run mode frequency simply by connecting a
resistor R17 between pin#2 (RF) of the L6585DE and GND. Each curve is related to a value
of the C13 capacitor and is depicted in Figure 4. Pin#3 (EOI) of the L6585DE is driven by
the internal logic in order to set the frequency during the startup.
Pin#4 (Tch) of the L6585DE is connected to the parallel of a resistor R18 and C11 and is
used to define the protection time. Pin#6 (EOL) of the L6585DE is the input of an internal
window comparator that can be triggered by a voltage variation due to a rectifying effect.
The reference of this comparator and the amplitude of the window can be set by connecting
a suitable resistor to pin#5 (EOLP) of the L6585DE. The reference of this comparator can be
set at a fixed voltage or at the same voltage as pin#7 (CTR) of the L6585DE.
6/25 Doc ID 018857 Rev 1
AN3407 Main characteristics and circuit description
Figure 4. Oscillator characteristics
Pin #14 (HBCS) of the L6585DE is equipped with a current sensing and a dedicated
overcurrent management system. When the EOI voltage reaches 1.9 V, the IC enters run
mode and the switching frequency is set only by R17 (RRUN). In Figure 5 the protection
thresholds are shown. They are sensed by the circuit C18, R26, D8, D9, R27, and C19 and
are fed into the L6585DE pin#14 (HBCS).
Figure 5. Half-bridge protection thresholds during run mode
2.4 Output voltage feedback loop
The output voltage is kept stable by means of a feedback loop implementing a typical circuit
using U3 (TS2431) modulating the current in the optocoupler diode. On the primary side,
R34 connecting pin#2 (RF) of the L6585DE to the optocoupler's phototransistor allows
modulating the L6585DE oscillator frequency, thus keeping the output voltage regulated.
R17 connects the same pin to ground and sets the minimum switching frequency.
Doc ID 018857 Rev 1 7/25
Main characteristics and circuit description AN3407
Figure 6. Electrical schematic
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AN3407 Efficiency measurements
3 Efficiency measurements
Ta bl e 1 shows the overall efficiency, measured at 115 VAC - 60 Hz. Ta bl e 2 shows the overall
efficiency, measured at 230 V
- 50 Hz.
AC
Table 1. Efficiency at 115 V
Load
Vout (V) Iout (A) Pout (W) Pin (W) PF Eff (%)
25% 48.67 0.525 25.55 29.30 0.982 87.21
50% 48.67 1.050 51.10 55.87 0.996 91.47
75% 48.67 1.560 75.93 82.01 0.995 92.58
100% 48.67 2.086 101.53 109.28 0.991 92.90
Table 2. Efficiency at 230 V
Load
Vout (V) Iout (A) Pout (W) Pin (W) PF Eff (%)
25% 48.67 0.525 25.55 29.45 0.793 86.76
50% 48.67 1.048 51.01 55.59 0.924 91.76
75% 48.67 1.560 75.93 81.06 0.966 93.67
100% 48.67 2.083 101.38 107.46 0.980 94.34
AC
115 V
Average eff. 91.04
AC
230 V
- 60 Hz
AC
- 50Hz
AC
Average eff. 91.63
The overall circuit efficiency is measured at different loads, powering the board at the two
nominal input mains voltages. The measures have been done after 30 minutes at load. The
high efficiency of the PFC working in transition mode and the very high efficiency of the
resonant stage working in ZVS provides for an overall efficiency better than 90%.
Figure 7 shows the efficiency at 25%, 50%, 75% and 100% load at 115 V
and 230 VAC.
AC
Figure 8 shows the efficiency at full load over the entire AC input voltage mains range.
Figure 9 shows the power factor (PF) versus load variations.
Doc ID 018857 Rev 1 9/25
Efficiency measurements AN3407
Figure 7. STEVAL-ILL038V1 demonstration board: efficiency vs. load
Figure 8. STEVAL-ILL038V1 demonstration board: full-load efficiency vs. V
Figure 9. STEVAL-ILL038V1 demonstration board: power factor vs. load
AC
10/25 Doc ID 018857 Rev 1
AN3407 Input current harmonics measurement
4 Input current harmonics measurement
The internal THD optimizer increases the performance when the mains voltage reaches
zero which reduces crossover distortion and avoids introducing offset. 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. The board has been
tested according to the European norm EN61000-3-2 Class-D, at full load and nominal input
voltage mains. Figure 10 and 11 show the measurement results.
Figure 10. EN61000-3-2 Class-D standard - 185 V
full load
Figure 11. EN61000-3-2 Class-D standard - 230 V
full load
/50 Hz, THD=4.86%, PF=0.993 at
AC
/50 Hz, THD=5.98%, PF=0.980 at
AC
Doc ID 018857 Rev 1 11/25
Input current harmonics measurement AN3407
Figure 12 and 13 show the waveforms of the input current and voltage at 115 VAC and 230
V
during full load.
AC
Figure 12. Input current waveforms - full load
at 115 V
AC
CH2: Vac-in CH4: Iac-in CH2: Vac-in CH3: Iac-in
Figure 13. Input current waveforms - full load
at 230 V
AC
12/25 Doc ID 018857 Rev 1
AN3407 Functional check
5 Functional check
5.1 PFC circuit
The waveforms measured in the PFC stage have been captured during full load operation at
nominal 115 V
envelope of the waveform of pin#12 (PFCS) is in phase with that of pin#8 (MULT) 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. The details of the
waveforms at switching frequency are measured in Figure 16 and 17.
and 230 VAC in Figure 14 and 15. It can be seen in both figures that the
AC
Figure 14. PFC stage waveforms at 115 V
CH1: MULT
full load
CH2: PFCS
CH4: Vout_PFC
AC
-
Figure 16. PFC stage waveforms at 115 VAC -
full load - detail
Figure 15. PFC stage waveforms at 230 VAC -
full load
CH1: MULT
CH2: PFCS
CH4: Vout_PFC
Figure 17. PFC stage waveforms at 230 VAC -
full load - detail
CH1: MULT
CH3: Vdrain_Q2
CH3: Vout_PFC
Doc ID 018857 Rev 1 13/25
CH1: MULT
CH3: Vdrain_Q2
CH4: Vout_PFC
Functional check AN3407
5.2 Half-bridge resonant LLC circuit
The waveforms are measured in the resonant stage ZVS operation in Figure 18. 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. The switching frequency
has been chosen around 94 kHz.
Figure 18 shows waveforms during steady-state operation of the circuit at full load. A slight
asymmetry of operating modes by each half portion of the sine wave is visible: one halfcycle is working at resonant frequency while the other half is working above the resonant
frequency. This is due to a small difference between each half’s secondary leakage
inductance of the transformer reflected to the primary side, providing two slightly different
resonant frequencies. This phenomenon is typically due to a different coupling of the
transformer’s secondary windings and in this case it is not an issue.
Figure 19 demonstrates that during one half-cycle the circuit is working below the resonant
frequency, while during the following half-cycle it is working at resonance frequency.
Waveforms relevant to the secondary side are shown: the rectifier’s reverse voltage is
measured by Ch3 and Ch4 on the right of the picture. It is a bit higher than the theoretical
value that would be 2 (VOUT+VF), hence about 100 V.
Figure 18. Primary side LLC waveforms at
115 V
CH1: VCC
- full load
AC
CH3: Res. Tank current
CH4: HB
Figure 19. Secondary side LLC waveforms at
230 VAC - full load
CH1: Vout
CH3: V_D7
CH4: V_D5
14/25 Doc ID 018857 Rev 1
AN3407 Functional check
The ripple and noise on the output voltage is shown on CH1. Figure 20 shows the waveform
during the high-frequency ripple of the circuit at full load. The peak-to-peak value is high but
it doesn't affect the application, in fact the converters regulating the current flowing in each
LED strip can reject the ripple. Figure 21 shows the waveform during the low-frequency
ripple of the circuit at full load.
Figure 20. High-frequency ripple on output
voltage at 115 V
- 60 Hz - full load
AC
CH1: Vout
5.3 Converter startup
The converter startup is captured in Figure 22 and 23. The converter begins operation
around 80 ms at 115 V
on voltage. The L6585DE starts switching and the PFC and HB output voltage starts
increasing.
and 230 VAC. This is the time needed to charge the VCC to turn-
AC
Figure 21. Low-frequency ripple on output
voltage at 115 VAC - 60 Hz - full load
CH1: Vout
Figure 22. Wake-up at 115 VAC - 60 Hz - full
CH1: VCC
load
CH3: VOUT
CH4: HB
Doc ID 018857 Rev 1 15/25
Figure 23. Wake-up at 230 VAC - 60 Hz - full
load
CH1: VCC
CH3: VOUT
CH4: HB
Bill of material AN3407
6 Bill of material
Table 3. STEVAL-ILL038V1 demonstration board: bill of material
Reference Part / value Tolerance % Voltage Manufacturer
BD1 GBU8J_DIP VISHAY
C1,C5,C9 470nF_DIP 305 VAC EPCOS
C2,C3,C4 5uF/800 V_DIP 800 V EPCOS
C6,C12 10 nF X7R 50 V
C7,C11 2.2 µF X7R 50 V
C8 0.33 µF X7R 50 V
C10 470 nF X7R 50 V
C13,C30 1 nF X7R 50 V
C14 0.1 µF_1206 X7R 50 V
C15,C16 4.7 µF 63 V_DIP 63 V EPCOS
C17 100 nF_1206 X7R 100 V
C18 220 pF_1206 X7R 1000 V AVX
C19 330 nF X7R 50 V
C20 15 nF_DIP 1000 V EPCOS
C21 2.2 nF_DIP Murata
C22,C31 220 nF X7R 50 V
C23 4.7 µF X7R 25 V
C25 47 µF_CaseD 20 V SANYO
C26 0.47 µF_1206 X7R 50 V
C27 2.2 µF_1206 X7R 50 V
C28 0.22 µF X7R 50 V
C29 15 nF X7R 50 V
D1 1N4007_DIP VISHAY
D2 STTH3L06U_SMB STMicroelectronics
D3,D4,D6,D8,D9,
D10,D11,D12
D5,D7 STPS10150CG STMicroelectronics
F1 4 A_DIP Littlefuse
J1 CN1 PHOENIX CONTACT
J2 CON2 PHOENIX CONTACT
L1 QTC21_DIP YU JING
1N4148 CHENMKO
L2 3.3 µH_DIP MAGI
16/25 Doc ID 018857 Rev 1
AN3407 Bill of material
Table 3. STEVAL-ILL038V1 demonstration board: bill of material (continued)
Reference Part / value Tolerance % Voltage Manufacturer
Q1,Q3 STF8NM60N_DIP 600 V STMicroelectronics
Q2 STF21NM60N_DIP 600 V STMicroelectronics
Q4 STQ1HNK60R_DIP STMicroelectronics
Q5,Q6,Q7 BC847 CHENMKO
RV1 VARISTOR 300 VAC EPCOS
R1,R3 1 MΩ_1206 1%
R2 1.3 MΩ_1206 1%
R4 1.1 MΩ_1206 1%
R5 150 kΩ_1206 1%
R6,R9 2 MΩ_1206 1%
R7 1.5 MΩ_1206 1%
R8 18 kΩ 1%
R10 56 kΩ_1206 1%
R11 19.6 kΩ 1%
R13 51 kΩ 1%
R14 390 kΩ_1206 1%
R15,R32 120 kΩ 1%
R16,R17,R36 27 kΩ 1%
R18 270 kΩ 1%
R19 680 kΩ 1%
R20,R21,R24 22 Ω 5%
R23 0.15_DIP 1%
R25 110 kΩ_1206 1%
R26 110_1206 1%
R27 100 Ω 1%
R28 3 MΩ_1206 1%
R29 1.8 MΩ_1206 1%
R30 220 kΩ 1%
R31,R37 4.7 kΩ 5%
R33 1_1206 5%
R34 22 kΩ 1%
R35 620 Ω 1%
R38 49.9 kΩ 1%
R39 2.2 kΩ 1%
R40 12 kΩ_1206 1%
Doc ID 018857 Rev 1 17/25
Bill of material AN3407
Table 3. STEVAL-ILL038V1 demonstration board: bill of material (continued)
Reference Part / value Tolerance % Voltage Manufacturer
R41 15 kΩ 1%
R44 2.7 kΩ 1%
T1 QP2520_DIP YU JING
T2 LP2920_DIP YU JING
U1 L6585DE STMicroelectronics
U2 SFH617A VISHAY
U3 TS2431 STMicroelectronics
ZD1 24 V CHENMKO
ZD2 12 V CHENMKO
ZD3 15 V CHENMKO
Figure 24. PCB: topside and through-hole components
Figure 25. PCB: bottomside and SMD components
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AN3407 Bill of material
Figure 26. PCB: topside placement
Figure 27. PCB: bottomside placement
Doc ID 018857 Rev 1 19/25
EMI choke AN3407
7 EMI choke
Figure 28. EMI: OTC21V-4S vertical type EMI choke
MYLAR FILM
22.0 MAX
22.0 MAX
26.0 MAX
14±0.5
32
Table 4. Transformer specifications
Ae 26.1 mm
No. Start Finish Wire Winding Turns Inductance DCR (mΩ)
L1 1 4 0.55 Φ* 48 11.0 µH min 200 max.
L2 2 3 0.55 Φ* 48 96 µH min 200 max.
2
Wiring spec. for resonant transformer
Note: Class B insulation system: SBI4.2
Hi-pot test: 1.5 kV, N1 to N2, 1.5 kV, N1 to core, 1.5 kV, N2 to core
Core spec-OTC21
Le 55.2 mm
3.5±0.3
12
15.0±0.5
AM09845v1
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AN3407 PFC coil specifications
8 PFC coil specifications
Figure 29. PFC: QP2520V-vertical type for PFC choke
Table 5. Transformer specifications
Ae 118.0 mm
No. Start Finish Wire Winding Turns Inductance DCR (mΩ)
L1 1.2 3.4
L2 7 6 0.3 Φ* 1c AUX 6±0.5
2
Wiring spec. for resonant transformer
0.1Φ 35c*
1p(Litz)
Note: Class B insulation system: SBI4.2
with standing voltage: 1.0 kV/3 sec/AC/5 mA, primary to secondary, 0.5 kV/1 sec/AC/3 mA,
primary to core, 0.5 kV/1 sec/AC/3 mA, secondary to core
Doc ID 018857 Rev 1 21/25
!-V
Core spec-QP2520
Le 46 mm
Primary 62±0.5 580 µH ±10% 280 max.
Transformer specifications AN3407
9 Transformer specifications
Figure 30. Transformer: LP2920H - horizontal type for LLC transformer
-!8
-!8
-!8
0.
9*$#
!-V
Table 6. Transformer specifications
Ae 112.0 mm
No. Start Finish Wire Winding Turns Inductance DCR (mΩ)
L1 1 3
L2 5 6
L3 9 8
L4 11 10
Lk 1 3
2
Wiring spec. for resonant transformer
0.1Φ 30c*
1p(Litz)
0.28 Φ* 1c
(TEX-E)
0.1 Φ* 60C*
1p (Litz)
0.1 Φ* 60c*
1p (Litz)
0.1 Φ* 30c*
1p (Litz)
Note: Class B insulation system: SBI4.2
with standing voltage: 3.0 kV/1 sec/AC/5 mA, primary to secondary, 2.5 kV/1 sec/AC/3 mA,
primary to core, 1.0 kV/1 sec/AC/3 mA, secondary to core
Core spec-LP2920
Le 79.6 mm
Primary 47±0.5 770 µH ±10%
AUX 3±0.5
Second 9±0.5
Second 9±0.5
Primary 47±0.5 170 µH ±10% Sec.short
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AN3407 References
10 References
1. L6585DE datasheet, STMicroelectronics
2. L6562A datasheet, STMicroelectronics
3. L6599 datasheet, STMicroelectronics
4. Application notes: AN2870, AN3106, STMicroelectronics
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Revision history AN3407
11 Revision history
Table 7. Document revision history
Date Revision Changes
30-Aug-2011 1 Initial release.
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AN3407
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