AN3172

Application note
19 V - 90 W adapter with PFC for laptop computers using the
L6563H and L6599A

Introduction
This application note describes the performance of a 90 W, wide-range mains, power-factor-
corrected, AC-DC adapter demonstration board. Its electrical specification is tailored on a
typical hi-end portable computer power adapter.
The architecture is based on a two-stage approach; a front-end PFC pre-regulator based on
the L6563H TM PFC controller and a downstream LLC resonant half-bridge converter using
the new L6599A resonant controller. Thanks to the chipset used, the main aspects of this
design are very high efficiency, compliance with ENERGY STAR® Eligibility Criteria (EPA
rev. 2.0 EPS), and very low input consumption at no-load (<0.3 W).

Figure 1. STEVAL-ISA148V1: 90 W adapter demonstration board

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 Contents AN3172

Contents

1 Main characteristics and circuit description . . . . . . . . . . . . . . . . . . . . . 5

1.1 Startup sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.2 Brownout protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.3 Fast voltage feed forward . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.4 Resonant power stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.5 Output voltage feedback loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.6 L6599A overload and short-circuit protection . . . . . . . . . . . . . . . . . . . . . . . 8
1.7 PFC overvoltage and open-loop protection . . . . . . . . . . . . . . . . . . . . . . . . 8
1.8 Standby power saving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2 Efficiency measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.1 Light-load operation efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3 Harmonic content measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4 Functional check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.1 Standby and no-load operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.2 Overcurrent and short-circuit protection . . . . . . . . . . . . . . . . . . . . . . . . . . 16

5 Thermal map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

6 Conducted emission pre-compliance test . . . . . . . . . . . . . . . . . . . . . . 20

7 BOM list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

8 PFC coil specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

8.1 Mechanical aspect and pin numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

9 Transformer specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
9.1 Mechanical aspect and pin numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

10 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

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 AN3172 List of figures

List of figures

Figure 1. STEVAL-ISA148V1: 90 W adapter demonstration board . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Figure 2. Electrical diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 3. Efficiency vs. output power diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 4. Light-load efficiency diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 5. Compliance to EN61000-3-2 at 230 Vac - 50 Hz, full load . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 6. Compliance to JEITA-MITI at 100 Vac - 50 Hz, full load. . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 7. Resonant stage waveforms at 115 V - 60 Hz - full load . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 8. Resonant stage waveforms at 230 V - 50 Hz - full load . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 9. Rectifier waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 10. Startup waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 11. No-load operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 12. No-load operation - detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 13. Transition full load to no-load at 265 Vac - 50 Hz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure 14. Transition no-load to full load at 265 Vac - 50 Hz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure 15. Short-circuit at full load and 115 Vac - 60 Hz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 16. Thermal map at 115 Vac - 60 Hz - full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 17. Thermal map at 230 Vac - 50 Hz - full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 18. CE Peak measurement at 115 Vac and full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 19. CE peak measurement at 230 Vac and full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 20. PFC coil electrical diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 21. PFC coil mechanical aspect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 22. Transformer electrical diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Figure 23. Transformer overall drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

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 List of tables AN3172

List of tables

Table 1. Overall efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Table 2. Light-load efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Table 3. Thermal maps reference points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Table 4. STEVAL-ISA148V1 demonstration board: BOM list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Table 5. PFC coil winding data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Table 6. Transformer winding data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Table 7. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

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 AN3172 Main characteristics and circuit description

1 Main characteristics and circuit description

The main features of the SMPS are:

• Universal input mains range: 90÷264 Vac - frequency 45 ÷ 65 Hz
• Output voltage: 19 V at 4.75 A continuous operation
• Mains harmonics: Acc. to EN61000-3-2 Class-D or JEITA-MITI Class-D
• Standby mains consumption: <0.3 W at 230 Vac
• Efficiency at nominal load: Better than 90 % at full load
• EMI: According to EN55022-Class-B
• Safety: According to EN60950
• Dimensions: 65x151 mm, 25 mm component maximum height
• PCB: Double side, 70 µm, FR-4, Mixed PTH/SMT
The circuit is composed of two stages; a front-end PFC using the L6563H and an LLC
resonant converter based on the L6599A.
The PFC stage works as the pre-regulator and powers the resonant stage with a constant
voltage of 400 V. The downstream converter operates only if the PFC is on and regulating its
output voltage. In this way, the resonant stage can be optimized for a narrow input voltage
range, improving the efficiency and the primary side power components.

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 Main characteristics and circuit description AN3172

1.1 Startup sequence

As previously indicated, the PFC acts as master and the resonant stage can operate only if
the PFC output is delivering its nominal output voltage. Therefore the circuit is designed so
that at startup the PFC starts first, then the downstream converter turns-on. At the
beginning, the L6563H is supplied by the integrated high voltage startup circuit; once the
PFC starts switching, a charging pump connected to the PFC inductor supplies both PFC
and resonant controllers. Once both stages have been activated, the controllers are also
supplied by the auxiliary winding of the resonant transformer, assuring correct supply
voltage, even during standby operation.
Because the L6563H integrated HV startup circuit is turned off, and therefore not dissipative
during normal operation, it makes a significant contribution to power consumption reduction
once the power supply operates at light-load, in agreement with standby worldwide
standards currently required.

1.2 Brownout protection

Brownout protection prevents the circuit from working with abnormal mains levels. It is easily
achieved using the RUN pin (#12) of the L6563H; this pin is connected through a resistor
divider to the VFF pin (#5) providing the information of the mains voltage peak value. An
internal comparator allows IC operations if the mains level is correct, within the nominal
limits. At startup, if the input voltage is below 90 Vac (typ.), circuit operations are inhibited.
The L6599A has similar protection on the LINE pin (#7). It is used to prevent the resonant
converter from working with a too low input voltage which can cause incorrect capacitive
mode operation. If the bulk voltage (PFC output) is below 380 V, the resonant stage startup
is not allowed. The L6599A LINE pin internal comparator has a hysteresis allowing the turn-
on and turn-off voltage to be set independently. The turn-off threshold has been set to 300 V
in order to avoid capacitive mode operation but allow the resonant stage to operate even in
the case of mains sag and a consequent PFC output dip.

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 AN3172 Main characteristics and circuit description

1.3 Fast voltage feed forward

Voltage on the L6563H VFF pin (#5) has the same value as the peak value of the voltage on
the MULT pin (#3) and it is generated by the RC network (R15+R26, C12) connected to
VFF, completing an internal peak-holding circuit. This signal is necessary to derive
information on the RMS input voltage to compensate the loop gain which is mains voltage
dependent.
In general, if the VFF time constant is too small, the voltage generated is affected by a
considerable amount of ripple at twice the mains frequency. Because the VFF signal is fed
into the multiplier the excessive ripple causes distortion of the current reference resulting in
high THD and poor PF. On the other hand, if the time constant is set too large there is a
considerable delay in setting the right amount of feed-forward, resulting in excessive
overshoot or undershoot of the pre-regulator's output voltage in response to large line
voltage changes.
To overcome this issue, the L6563H implements the new fast voltage feed forward function.
As soon as the voltage on the VFF pin decreases from a set threshold (40 mV typically), a
mains dip is assumed and an internal switch rapidly discharges the VFF capacitor via a 10
kΩ resistor. Thanks to this feature it is possible to set an RC circuit with a long time
constant, assuring a low THD, but keeping a fast response to mains voltage variations.

1.4 Resonant power stage

The downstream converter implements the ST L6599A, incorporating all the functions
necessary to properly control the resonant converter with a 50 percent fixed duty cycle and
working with variable frequency.
The transformer uses the integrated magnetic approach, incorporating the resonant series
inductance. Therefore, no additional external coil is needed for the resonance.
The transformer configuration chosen for the secondary winding is centre tap and makes
use of a couple of power schottky rectifiers p/n STPS30H60CFP. A small LC filter has been
added on the output, filtering the high frequency ripple.
D15, R56, R62, R65, R66, Q5, and Q6 implement an output voltage “fast discharge” circuit,
quickly discharging the output capacitors when the converter is turned off. It has been
implemented to quickly decrease the residual output voltage once the converter is turned off
at no-load.

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 Main characteristics and circuit description AN3172

1.5 Output voltage feedback loop

The feedback loop is implemented by means of a typical circuit using a TL431 modulating
the current in the optocoupler diode.
On the primary side, R34 - connecting pin RFMIN (#4) to the optocoupler’s phototransistor -
closes the feedback loop and its value sets the maximum switching frequency at about 130
kHz. This value has been chosen to limit the switching losses at light-load operation. R31,
connecting the same pin to ground, sets the minimum switching frequency. The R-C series
R44 and C18 sets both soft-start maximum frequency and duration.

1.6 L6599A overload and short-circuit protection

The current into the primary winding is sensed by the lossless circuit R41, C27, D11, D10,
R39, and C25 and it is fed into the ISEN pin (#6). In the case of overcurrent, the voltage on
the pin overpasses an internal comparator threshold (0.8 V), triggering a protection
sequence. The capacitor (C45) connected to the DELAY pin (#2) is charged by an internal
150 µA current generator and is slowly discharged by the external resistor (R24). 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
pin decays because of the external resistor. The IC is soft-restarted as the voltage drops
below 0.3 V. In this way, under short-circuit conditions, the converter works intermittently
with very low average input power.

1.7 PFC overvoltage and open-loop protection

Both circuit stages, PFC and resonant, are equipped with their own overvoltage protections.
The L6563H PFC controller monitors its output voltage via the resistor divider connected to
a dedicated pin (PFC_OK, #7) protecting the circuit in the case of loop failures or
disconnection of the feedback loop divider. In the case where a fault condition is detected,
the PFC_OK circuitry latches the L6563H operations and, by means of the PWM_LATCH
pin (#8), it also latches the L6599A, via the DIS pin (#8). The converter is kept latched by the
L6563H HV circuit that supplies the IC charging the Vcc capacitor periodically. To resume
converter operation mains restart is necessary.

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 AN3172 Main characteristics and circuit description

1.8 Standby power saving

The board implements a burst-mode function allowing a significant power saving during
light-load operation.
The L6599A’s STBY pin (#5) senses the optocoupler’s collector voltage which is related to
the feedback control and is proportional to the output load. This signal is compared to an
internal reference (1.24 V); if the load decreases and the voltage on the STBY pin goes
lower than the reference, the IC enters an idle state and its quiescent current is reduced.
Once the voltage exceeds the reference by 50 mV, the controller restarts switching. Burst-
mode operation load threshold can be programmed by properly choosing the resistor
connecting the optocoupler to the RFMIN pin (R34). On this board the controller operates in
burst-mode if the load falls below ~15 W.
The L6563H implements its own burst-mode function. If the COMP voltage falls below 2.5 V,
the IC stops switching, causing an output voltage decrease, as a consequence the COMP
voltage rises again and the IC restarts switching.
In order to achieve a better load transient response, the PFC burst-mode operation is
partially forced by the resonant converter; once the L6599A stops switching due to load
drops, its PFC_STOP pin pulls down the L6563H’s PFC_OK pin, disabling PFC switching.
Thanks to this solution, the PFC is forced into idle state when the resonant stage is not
switching and rapidly wakes-up when the downstream converter restarts switching. This
solution prevents a significant drop of the bulk voltage in the case of abrupt load rising.

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 AN3172 Efficiency measurement

2 Efficiency measurement

EPA rev. 2.0 external power supply compliance verification.

Table 1 shows the no-load consumption and the overall efficiency, measured at the nominal
mains voltages. At 115 Vac the average efficiency is 89.96 %, while at 230 Vac it is 91.12 %.
Both values are much higher than the minimum required by EPA rev2.0 External power
supply limits (87 %).
Measurements are also given in Figure 3 for reference.
Even at no-load the board performance is superior; maximum no-load consumption at
nominal mains voltage is less than 250 mW only; even this value is significantly lower than
the 500 mW limit imposed by the ENERGY STAR program.

Table 1. Overall efficiency

Test 230 V-50 Hz 115 V-60 Hz

Vout Iout Pout Pin Eff. Vout Iout Pout Pin Eff.
[V] [A] [W] [W] [%] [V] [A] [W] [W] [%]

No load 18.98 0.00 0.00 0.246 ------ 18.97 0.00 0.00 0.235 ------
100 % load eff. 18.93 4.700 88.97 96.15 92.53 % 18.93 4.700 88.97 98.04 90.75 %
75 % load eff. 18.94 3.526 66.78 72.29 92.38 % 18.94 3.526 66.78 73.40 90.98 %
50 % load eff. 18.95 2.352 44.57 48.72 91.48 % 18.95 2.352 44.57 49.14 90.70 %
25 % load eff. 18.96 1.177 22.32 25.33 88.10 % 18.96 1.177 22.32 25.53 87.41 %
Average eff. 91.12 % 89.96 %

Figure 3. Efficiency vs. output power diagram










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 Efficiency measurement AN3172

2.1 Light-load operation efficiency

Measurement results are given in Table 2 and plotted in Figure 4. As seen, efficiency is
better than 55 % even for very light loads such as 500mW.

Table 2. Light-load efficiency

Test 230 V - 50 Hz 115 V - 60 Hz

Vout Iout Pout Pin Eff. Vout Iout Pout Pin Eff.
[V] [mA] [W] [W] [%] [V] [mA] [W] [W] [%]

0.25 W 18.89 13.06 0.247 0.643 38.37 % 18.89 13.06 0.247 0.62 39.60 %
0.5 W 18.89 26.83 0.507 0.911 55.63 % 18.89 26.83 0.507 0.869 58.32 %
1.0 W 18.89 51.92 0.981 1.415 69.31 % 18.89 51.93 0.981 1.404 69.87 %
1.5 W 18.89 78.90 1.490 2.014 74.00 % 18.89 78.90 1.490 2.010 74.15 %
2.0 W 18.89 105.9 2.000 2.608 76.67 % 18.89 105.9 2.000 2.610 76.61 %
2.5 W 18.89 130.2 2.459 3.145 78.17 % 18.89 130.2 2.459 3.152 78.01 %
3.0W 18.89 157.2 2.970 3.748 79.23 % 18.89 157.2 2.970 3.762 78.93 %
3.5 W 18.89 184.2 3.480 4.337 80.23 % 18.88 184.2 3.478 4.358 79.80 %
4.0 W 18.88 211.2 3.987 4.919 81.04 % 18.88 211.2 3.987 4.936 80.76 %
4.5 W 18.88 235.4 4.445 5.415 82.08 % 18.88 235.4 4.445 5.453 81.51 %
5.0 W 18.88 262.4 4.954 5.983 82.81 % 18.88 262.4 4.954 6.031 82.14 %

Figure 4. Light-load efficiency diagram





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 AN3172 Harmonic content measurement

3 Harmonic content measurement

The board has been tested according to the European standard EN61000-3-2 Class-D and
Japanese standard JEITA-MITI Class-D, at both the nominal input voltage mains. As shown
in Figure 5 and 6, the circuit is able to reduce the harmonics well below the limits of both
regulations.

Figure 5. Compliance to EN61000-3-2 at 230 Vac Figure 6. Compliance to JEITA-MITI at 100 Vac -
- 50 Hz, full load 50 Hz, full load

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THD = 5.13 % - PF = 0.965 THD = 3.89 % - PF = 0.996

On the bottom side of the diagrams the total harmonic distortion and power factor have also
been measured. The values in all conditions give a clear idea about the correct functioning
of the PFC.

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 Functional check AN3172

4 Functional check

The following are some waveforms relevant to the resonant stage during steady-state
operation. The selected switching frequency is about 100 kHz, in order to have a good trade
off between transformer losses and dimensions. The converter operates above the
resonance frequency. Figure 8 shows the resonant ZVS operation. It is worth noting that
both MOSFETs are turned on when resonant current is flowing through their body diodes
and drain-source voltage is zero.

Figure 7. Resonant stage waveforms at 115 V - Figure 8. Resonant stage waveforms at 230 V -
60 Hz - full load 50 Hz - full load

CH1: HB voltage CH2: CF pin voltage CH1: HB voltage CH2: HV FET gate
CH3: Vcc CH4: Res. tank current CH3: LV FET gate CH4: Res. tank current

In Figure 9 typical waveforms relevant to the secondary side are represented; it is worth
noting that the rectifiers reverse the working voltage and the current flowing through them.
The waveforms during the start at 90 Vac and full load are shown in Figure 10. It is possible
to note the sequence of the two stages; at power-on the L6563H and L6599A Vcc voltages
increase up to the turn-on thresholds of the two ICs. The PFC starts and its output voltage
increases from the mains rectified voltage to its nominal value. In the meantime the L6599A
is kept inactive by the LINE pin (#7) until the PFC voltage reaches the set threshold. Then
the resonant starts operating and the output voltage reaches the nominal level.

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 AN3172 Functional check

Figure 9. Rectifier waveforms Figure 10. Startup waveforms

CH1: D23 anode voltage CH2: D24 anode voltage CH1: HB voltage CH2: Vout PFC
CH3: D23 current CH4: D24 current CH3: Vcc CH4: Output voltage

4.1 Standby and no-load operation

In Figure 11 and Figure 12, some burst-mode waveforms are given. As seen, both L6599A
and L6563H operate in burst-mode. In Figure 11 it may also be noted that PFC and LLC
bursts are synchronized.

Figure 11. No-load operation Figure 12. No-load operation - detail

CH1: Q4 gate CH2: PFC gate voltage CH1: Q4 gate CH2: PFC gate voltage
CH3: STBY pin CH4: Output voltage CH3: STBY pin CH4: Output voltage

In Figure 13 and 14 the transitions from full load to no-load and vice versa, at maximum
input voltage, have been checked. The maximum input voltage has been chosen because it
is the most critical input voltage for transition; in fact at no-load the burst pulses have the
lower repetition frequency and the Vcc may drop, causing restart cycles of the controller. As
seen in Figure 13 and 14, both transitions are clean and there isn't any output voltage or
Vcc dip.

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 Functional check AN3172

Figure 13. Transition full load to no-load at 265 Figure 14. Transition no-load to full load at 265
Vac - 50 Hz Vac - 50 Hz

CH1:HB voltage CH2:Vcc CH1:HB voltage CH2:Vcc

CH3:D23 Anode CH4:Output current CH3:D23 Anode CH4:Output current

4.2 Overcurrent and short-circuit protection

The L6599A 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 referenced to 1.5 V in a second comparator. 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 to discharge the soft-start capacitor CSS.
Under output short-circuit, this operation results in a nearly constant peak primary current.
With the L6599A the user can externally program 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 do not cause any other action, therefore providing the system
with immunity to short duration phenomena. If, instead, the overload condition continues, a
protection procedure is activated which shuts down the L6599A and, in the case of
continuous overload/short-circuit, results in continuous intermittent operation with a user
defined duty cycle. This function is realized with the DELAY pin (#2), by means of a
capacitor C45 and the parallel resistor R24 connected to ground. When the voltage on the
ISEN pin exceeds 0.8V the first OCP comparator, in addition to discharging CSS, turns on
an internal 150 µA current generator that, via the DELAY pin, charges C45. When the
voltage on C45 is 3.5 V, the L6599A stops switching and the PFC_STOP pin is pulled low.
Also the internal generator is turned off, so that C45 is now slowly discharged by R24. The
IC restarts when the voltage on C45 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
is triggered, the L6599A shuts down and the operation is resumed after an off-on cycle.

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 AN3172 Functional check

Figure 15. Short-circuit at full load and 115 Vac - 60 Hz

CH1: HB Voltage CH3: DELAY pin CH4: Output current

In Figure the narrow operating time with respect to the off time of the converter may be
seen; consequently, the average output current, as well as the average primary current, are
very low, avoiding over-heating of components and consequent failure.

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 Thermal map AN3172

5 Thermal map

In order to check the design reliability, a thermal mapping by means of an IR Camera was
done. In Figure 16 and 17 the thermal measurements of the board, component side, at
nominal input voltage, are shown. Some pointers, visible in the images, have been placed
across key components or showing high temperature. The ambient temperature during both
measurements was 27 °C.

Figure 16. Thermal map at 115 Vac - 60 Hz - full load

Figure 17. Thermal map at 230 Vac - 50 Hz - full load

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 AN3172 Thermal map

Table 3. Thermal maps reference points

Point Reference Description

A L1 EMI filtering inductor

B D1 Bridge rectifier
C L2 PFC inductor – hottest point
D D4 PFC output diode
E Q1 PFC MOSFET
F-G Q3 & Q4 Resonant HB MOSFETs
H-I T1 Resonant power transformer
J-K D23 & D24 Output rectifiers

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 Conducted emission pre-compliance test AN3172

6 Conducted emission pre-compliance test

The following figures are the average measurement of the conducted noise at full load and
nominal mains voltages. The limits shown in the images are EN55022 Class-B, which is the
most popular standard for domestic equipment and has more severe limits compared to
Class-A, dedicated to IT technology equipment. As seen in Figure 18 and 19, in all test
conditions the measurements are far below the limits.

Figure 18. CE Peak measurement at 115 Vac and full load

Figure 19. CE peak measurement at 230 Vac and full load

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 AN3172 BOM list

7 BOM list

Table 4. STEVAL-ISA148V1 demonstration board: BOM list

Part type/ Case style
Des. Description Supplier
part value /package

C1 470 nF 9.0 × 18.0 p.15 mm X2 - MKP FILM CAP - B32922C3474K EPCOS

C10 1 nF 0805 50 V cercap - general purpose AVX
C11 2n2F 0805 50 V cercap - general purpose AVX
C12 1 uF 0805 25 V cercap - general purpose AVX
C13 680 nF 1206 25 V cercap - general purpose AVX
C14 68 nF 0805 50 V cercap - general purpose AVX
C15 47 uF DIA6.3X11 (mm) 50 V aluminium elcap - YXF series - 105 °C RUBYCON
C16 2n2F 1206 50 V cercap - general purpose AVX
C17 220 pF 0805 50 V - 5 % - C0G - cercap AVX
C18 4.7 uF 1206 6.3 V cercap - general purpose AVX
C19 100 nF 1206 50 V cercap - general purpose AVX
C2 2n2F DWG Y1 safety cap. DE1E3KX222M MURATA
C20 2n2F DWG Y1 safety cap. DE1E3KX222M MURATA
C21 2n2F DWG Y1 safety cap. DE1E3KX222M MURATA
C22 220 pF 0805 50 V cercap - general purpose AVX
C23 10 nF 0805 50 V cercap - general purpose AVX
C24 100 uF DIA10X12.5 (mm) 50 V aluminium elcap - YXF series - 105 °C RUBYCON
C25 330 nF 0805 50 V cercap - general purpose AVX
C26 10 uF DIA6.3X11 (mm) 50 V aluminium elcap - YXF series - 105 °C RUBYCON
C27 220 pF 5x3 mm 500 V cercap - 5MQ221KAAAA AVX
C28 22 nF 5x18 p.15 mm 1000 V - mkp film cap - B32652A0223K000 EPCOS
C29 470 uF DIA10X20 (mm) 35 V aluminium elcap - ZL series - 105 °C RUBYCON
C3 2n2F DWG Y1 safety cap. DE1E3KX222M MURATA
C30 470 uF DIA10X20 (mm) 35 V aluminium elcap - ZL series - 105 °C RUBYCON
C31 100 uF DIA8X11 (mm) 35 V aluminium elcap - YXF series - 105 °C RUBYCON
C32 100 nF 0805 50 V cercap - general purpose AVX
C33 470 pF 0805 50 V - 5 % - C0G - cercap AVX
C34 100 nF 0805 50 V cercap - general purpose AVX
C36 1 uF DIA6.3X11 (mm) 50 V aluminium elcap - YXF series - 105 °C RUBYCON
C37 10nF 0805 50 V cercap - general purpose AVX
C39 100 nF 0805 50 V cercap - general purpose AVX

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 BOM list AN3172

Table 4. STEVAL-ISA148V1 demonstration board: BOM list (continued)

Part type/ Case style
Des. Description Supplier
part value /package

C4 470 nF 9.0 × 18.0 p.15 mm X2 - MKP film cap - B32922C3474K EPCOS

C40 100 nF 1206 50 V cercap - general purpose AVX
C43 4n7F 1206 50 V cercap - general purpose AVX
C44 10 nF 1206 50 V cercap - general purpose AVX
C45 220 nF 0805 25 V cercap - general purpose AVX
C46 N.M. 0805 Not mounted
C5 470 nF 7.0 x 16.0 p. 22.5 400 V - film cap - B32673Z5474 EPCOS
C6 4N7 0805 50 V cercap - general purpose AVX
C7 100 nF PTH 100 V cercap - general purpose AVX
C8 10 uF DIA6.3X11 (mm) Aluminium elcap - YXF series - 105 °C RUBYCON
C9 68 uF Dia. 18X32 mm 450 V aluminium elcap - KXG series - 105 °C United chemicon
D1 GBU8J STYLE GBU Single-phase bridge rectifier VISHAY
D10 LL4148 Minimelf SOD-80 High speed signal diode VISHAY
D11 LL4148 Minimelf SOD-80 High speed signal diode VISHAY
D12 N.M. Minimelf SOD-80 Not mounted VISHAY
D13 N.M. Minimelf SOD-80 Not mounted VISHAY
D14 N.M. Minimelf SOD-80 Not mounted
D15 BZV55-C15 Minimelf SOD-80 Zener diode VISHAY
D16 LL4148 Minimelf SOD-80 High speed signal diode VISHAY
D17 N.M. Minimelf SOD-80 Not mounted
D18 LL4148 Minimelf SOD-80 High speed signal diode VISHAY
D19 LL4148 Minimelf SOD-80 High speed signal diode VISHAY
D2 LL4148 Minimelf SOD-80 High speed signal diode VISHAY
D20 BZV55-C15 Minimelf SOD-80 Zener diode VISHAY
D21 BZV55-C15 Minimelf SOD-80 Zener diode VISHAY
D22 LL4148 Minimelf SOD-80 Fast switching diode VISHAY
D23 STPS30H60CFP TO-220FP Power Schottky rectifier STMicroelectronics
D24 STPS30H60CFP TO-220FP Power Schottky rectifier STMicroelectronics
D3 1N4005 DO-41 General purpose rectifier VISHAY
D4 STTH2L06 DO-41 Ultrafast high voltage rectifier STMicroelectronics
D5 LL4148 Minimelf SOD-80 High speed signal diode VISHAY
D6 LL4148 Minimelf SOD-80 High speed signal diode VISHAY
D7 LL4148 Minimelf SOD-80 High speed signal diode VISHAY
D8 BZV55-B27 Minimelf SOD-80 Zener diode VISHAY

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 AN3172 BOM list

Table 4. STEVAL-ISA148V1 demonstration board: BOM list (continued)

Part type/ Case style
Des. Description Supplier
part value /package

D9 STPS1L60A SMA Power Schottky rectifier STMicroelectronics

F1 FUSE T4A 8.5x4 p.5.08mm Fuse 4A - time lag - 3921400 Littlefuse
HS1 HEAT-SINK DWG Heat sink for D1, Q1, Q3, Q4
HS2 HEAT SINK DWG Heat sink for D23, D24
J1 MKDS 1,5/ 3-5,08 DWG PCB term. block, screw conn.,pitch 5mm 3 W. Phoenix contact
J2 MKDS 1,5/ 2-5,08 DWG PCB term. block, screw conn.,pitch 5mm 2 W. Phoenix contact
JPX1 Jumper Wire Bare copper wire jumper
JPX2 Jumper Wire Bare copper wire jumper
JPX3 Jumper Wire Bare copper wire jumper
L1 2019.0002 CM inductor 2x18mH 1.8A MAGNETICA
L2 1974.0002 DWG PFC inductor - 0.52mH (X08141-01-B) MAGNETICA
L3 1071.0083 DWG 1 uH - 5 A inductor MAGNETICA
Q1 STF12NM50N TO-220FP N-channel power MOSFET STMicroelectronics
Q10 BC847C SOT-23 NPN small signal BJT VISHAY
Q2 BC857C SOT-23 PNP small signal BJT VISHAY
Q3 STF7NM50N TO-220FP N-channel power MOSFET STMicroelectronics
Q4 STF7NM50N TO-220FP N-channel power MOSFET STMicroelectronics
Q5 BC847C SOT-23 NPN small signal BJT VISHAY
Q6 BC847C SOT-23 NPN small signal BJT VISHAY
Q7 N.M. SOT-23 PNP small signal BJT - not used
Q9 BC847C SOT-23 NPN small signal BJT VISHAY
R1 3M3 1206 SMD STD film res, 1/4 W, 5 %, 250 ppm/°C VISHAY
R10 27 K 0805 SMD STD film res, 1/8 W, 1 %, 100 ppm/°C VISHAY
R11 2M2 1206 SMD STD film res, 1/4 W, 1 %, 100 ppm/°C VISHAY
R12 2M2 1206 SMD STD film res, 1/4 W, 1 %, 100 ppm/°C VISHAY
R13 8K2 1206 SMD STD film res, 1/4 W, 1 %, 100 ppm/°C VISHAY
R14 51 K 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R15 56 K 1206 SMD STD film res, 1/4 W, 1 %, 100 ppm/°C VISHAY
R16 4K7 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R17 2M2 1206 SMD STD film res, 1/4 W, 1 %, 100 ppm/°C VISHAY
R18 82 K 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R19 56 K 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R2 3M3 1206 SMD STD film res, 1/4 W, 5 %, 250 ppm/°C VISHAY
R20 0R0 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY

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 BOM list AN3172

Table 4. STEVAL-ISA148V1 demonstration board: BOM list (continued)

Part type/ Case style
Des. Description Supplier
part value /package

R21 39 R 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
SFR25 axial stand. film res, 0.4 W, 5 %, 250
R22 0R47 PTH VISHAY
ppm/°C
SFR25 axial stand. film res, 0.4 W, 5 %, 250
R23 0R68 PTH VISHAY
ppm/°C
R24 1 Meg 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R25 56 R 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R26 1 Meg 0805 SMD STD film res, 1/8 W, 1 %, 100 ppm/°C VISHAY
R27 470 R 1206 SMD STD film res, 1/4 W, 5 %, 250 ppm/°C VISHAY
R28 33 K 0805 SMD STD film res, 1/8 W, 1%, 100 ppm/°C VISHAY
R29 1K0 1206 SMD STD film res, 1/4 W, 5 %, 250 ppm/°C VISHAY
R3 1 Meg 1206 SMD STD film res, 1/4 W, 1 %, 100 ppm/°C VISHAY
R30 10 R 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R31 33 K 0805 SMD STD film res, 1/8 W, 1 %, 100 ppm/°C VISHAY
R32 47 R 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R33 N.M. 0805 Not mounted
R34 5K1 1206 SMD STD film res, 1/4 W, 1 %, 100 ppm/°C VISHAY
R35 180 K 0805 SMD STD film res, 1/8 W, 1 %, 100 ppm/°C VISHAY
R36 N.M. 0805 Not mounted
R37 220 K 1206 SMD STD film res, 1/4 W, 5 %, 250 ppm/°C VISHAY
R38 56 R 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R39 180 R 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R4 4M7 0805 SMD STD film res, 1/8W, 5 %, 250 ppm/°C VISHAY
R40 0R0 1206 SMD STD film res, 1/4 W, 5 %, 250 ppm/°C VISHAY
SFR25 axial stand. film res, 0.4 W, 5 %, 250
R41 100 R PTH VISHAY
ppm/°C
R42 10 K 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R43 N.M. 0805 Not mounted
R44 12 K 1206 SMD STD film res, 1/4 W, 5 %, 250 ppm/°C VISHAY
R45 N.M. 0805 Not mounted
R46 100 K 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R47 1K5 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R48 120 K 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R49 39 K 0805 SMD STD film res, 1/8 W, 1 %, 100 ppm/°C VISHAY
R5 10 R 1206 SMD STD film res, 1/4 W, 5 %, 250 ppm/°C VISHAY

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Table 4. STEVAL-ISA148V1 demonstration board: BOM list (continued)

Part type/ Case style
Des. Description Supplier
part value /package

R50 6K2 0805 SMD STD film res, 1/8 W, 1 %, 100 ppm/°C VISHAY
R51 120 K 0805 SMD STD film res, 1/8 W, 1 %, 100 ppm/°C VISHAY
R52 12 K 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R53 2K2 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R54 0R0 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R55 2K7 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R56 18 K 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R57 47R 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R58 100 K 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R59 100 K 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R6 NTC 2R5-S237 DWG NTC resistor P/N B57237S0259M000 EPCOS
R60 10 K 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R61 2K7 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R62 4K7 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R65 47K 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R66 2K2 1206 SMD STD film res, 1/4 W, 5 %, 250 ppm/°C VISHAY
R67 N.M. 0805 Not mounted
R68 N.M. 1206 Not mounted
R69 4K7 0805 SMD STD film res, 1/8 W, 5 %, 250 ppm/°C VISHAY
R7 1Meg 1206 SMD STD film res, 1/4 W, 1 %, 100 ppm/°C VISHAY
R8 1Meg 1206 SMD STD film res, 1/4 W, 1 %, 100 ppm/°C VISHAY
R9 62 K 0805 SMD STD film res, 1/8 W, 1 %, 100 ppm/°C VISHAY
T1 1860.0032 DWG, ETD34 Resonant power transformer MAGNETICA
U1 L6563H SO-16 High voltage startup TM PFC controller STMicroelectronics
U2 L6599AD SO-16 Improved HV resonant controller STMicroelectronics
U3 SFH617A-4 DIP-4, 10.16 mm Optocoupler Infineon
U4 TL431AIZ TO-92 Programmable shunt voltage reference STMicroelectronics
Z1 PCB REV. 1.0

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 PFC coil specification AN3172

8 PFC coil specification

General description and characteristics:

• Application type: consumer, home appliances
• Transformer type: open
• Coil former: vertical type, 6+6 pins
• Max. temp. rise: 45 ºC
• Max. operating ambient temperature: 60 ºC
• Mains insulation: n.a.
• Unit finishing: varnished
Electrical characteristics:
• Converter topology: boost, transition mode
• Core type: PQ26/20-PC44 or equivalent
• Min. operating frequency: 40 kHz
• Typical operating frequency: 120 kHz
• Primary inductance: 520 µH±15 % at 1 kHz-0.25 V
Electrical diagram and winding characteristics:

Figure 20. PFC coil electrical diagram

 

 

$0Y

Table 5. PFC coil winding data

Pins Windings DC resistance Number of turns Wire type

11 - 3 AUX 125 mΩ 5.5 φ 0.28 mm – G2

5-9 PRIMARY 267 mΩ 57.5 30xφ 0.1 mm – G1

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 AN3172 PFC coil specification

8.1 Mechanical aspect and pin numbering

• Maximum height from PCB: 22 mm
• Coil former type: vertical, 6+6 Pins (Pins #1, 2, 4, 6, 7, 10, and 12 are removed)
• Pin distance: 3.81 mm
• Row distance: 25 mm
• 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.

Figure 21. PFC coil mechanical aspect

Manufacturer:
• MAGNETICA, R. Volpini - Italy
• Inductor P/N: 1974.0002

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 Transformer specifications AN3172

9 Transformer specifications

General description and characteristics:

• Application type: consumer, home appliances
• Transformer type: open
• Coil Former: horizontal type, 7+7 pins, two slots
• Max. temp. rise: 45 ºC
• Max. operating ambient temperature: 60 ºC
• Mains insulation: Acc. with EN60065
Electrical characteristics:
• Converter topology: half-bridge, resonant
• Core type: ETD34-PC44 or equivalent
• Min. operating frequency: 60 kHz
• Typical operating frequency: 100 kHz
• Primary inductance: 1200 µH±8 % at 1 kHz-0.25 V (a)
• Leakage inductance: 200 µH at 100 kHz-0.25 V (b)
Electrical diagram and winding characteristics:

Figure 22. Transformer electrical diagram





 




$0Y

Table 6. Transformer winding data

Pins Winding DC resistance Number of turns Wire type

2-4 Primary 235 mΩ 50 30xφ 0.1 mm – G1

13-12 SEC - A(1) 9 mΩ 5 90xφ 0.1 mm – G1
10-9 SEC – B (1)
9 mΩ 5 90xφ 0.1 mm – G1
5-6 AUX (2) 94 mΩ 4 φ 0.28 mm – G2
1. Secondary windings A and B are in parallel
2. Aux winding is wound on top of primary winding

a. Measured between pins 2-4

b. Measured between pins 2-4 with only one secondary winding shorted

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 AN3172 Transformer specifications

9.1 Mechanical aspect and pin numbering

• Maximum Height from PCB: 30mm
• Coil Former Type: horizontal, 7+7 pins (pins #1 and 7 are removed)
• Pin distance: 5.08mm
• Row distance: 25.4mm

Figure 23. Transformer overall drawing

Manufacturer:
• MAGNETICA, R. Volpini - Italy
• Transformer P/N: 1860.0032

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 Revision history AN3172

10 Revision history

Table 7. Document revision history

Date Revision Changes

14-Dec-2010 1 Initial release

Updated core product: from EVL6599A-90WADP to
03-Aug-2015 2
STEVAL-ISA148V1.

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 AN3172

IMPORTANT NOTICE – PLEASE READ CAREFULLY

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© 2015 STMicroelectronics – All rights reserved

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