dm00024649

AN3360
Application note
3.2 W LED power supply based on HVLED805
Introduction
This application note describes the demonstration board of the all-primary sensing switching
regulator HVLED805 and presents the results of its bench evaluation. The board
implements a 3.2 W (16 V / 0.2 A) wide range mains LED power supply with constant
current.
HVLED805 combines a high-performance low-voltage PWM controller chip and an 800 V
avalanche rugged power MOSFET in the same package. The PWM chip is a quasi-resonant
(QR) current mode controller IC specifically designed for QR ZVS (zero voltage switching at
switch turn-on) flyback converters. The device provides constant output current (CC)
regulation using primary sensing feedback. This eliminates the need for the optocoupler, the
secondary voltage reference, and also the current sensor, while still maintaining quite
accurate regulation. The device can provide a constant output voltage regulation (CV). This
makes the application able to work safely when the LED string opens due to a failure.
However, an auxiliary winding is required in the transformer to correctly perform CV/CC
regulation, the chip is able to power itself directly from the rectified mains. This is useful
during CC regulation, where the flyback voltage generated by the winding drops.
Figure 1.
July 2011
STEVAL-ILL037V1 demonstration board image
Doc ID 018586 Rev 2
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www.st.com
Contents
AN3360
Contents
1
Test board design and evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2
Transformer specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3
Efficiency measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4
Typical board waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
7
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
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AN3360
List of figures
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
STEVAL-ILL037V1 demonstration board image. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
For E26/E27 application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Electrical schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
PCB top side and through hole components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
PCB bottom side and SMD components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
EEE13-11 vertical type for under 10 W . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Output characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Normal operation at full load - at 115 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Normal operation at full load - at 230 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Normal operation at no load - at 115 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Normal operation at no load - at 230 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Short-circuit at 115 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Short-circuit at 230 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Startup at full load at 115 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Startup at full load at 230 VAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
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Test board design and evaluation
1
AN3360
Test board design and evaluation
As a reference design, a 3.2 W LED power supply based on HVLED805 is presented.
●
Table 1 summarizes the electrical specifications of the application
●
Table 2 provides the bill of material
●
Table 4 lists transformer specifications
The electrical schematic is shown in Figure 3 and the PCB layout in Figure 4. and 5.
Table 1.
Figure 2.
4/16
STEVAL-ILL037V1 demonstration board: electrical specifications
Parameter
Value
Input voltage range (VIN)
90 - 265 VAC
Mains frequency (fL)
50 - 60 Hz
Output power consumption
3.2 W
Output voltage
16 VDC (3~5 LEDs)
Output current
200 mA
Target average efficiency
>70%
For E26/E27 application
Doc ID 018586 Rev 2
Doc ID 018586 Rev 2
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Figure 3.
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,
AN3360
Test board design and evaluation
Electrical schematic
0
!-V
5/16
Test board design and evaluation
Table 2.
6/16
AN3360
STEVAL-ILL037V1 demonstration board bill of material
Reference
Part
BD1
BR81D
C1
1000 µF_DIP
C2
1 nF_1206
C3,C4
4.7 µF_DIP
C5
2.2 nF_DIP
C6
22 µF_1206
X5R
C7
6.8 nF
X7R
C8
470 nF
X7R
C9
22 nF
X7R
C10
470 nF
X7R
D1
STPS1H100U
STMicroelectronics
D2
STTH1L06_SMB
STMicroelectronics
D3
1N4148
CHENMKO
F1
1A_DIP
L1
22 µH_DIP
R1
110 kΩ_1206
5%
R2
150 kΩ_1206
5%
R4
5.6 Ω_1206
1%
R5
3.9 Ω_1206
1%
R6
3.9 kΩ
1%
R7
12 kΩ
1%
R8
NC
R9
33 kΩ
1%
R10
10 Ω_1206
5%
T1
QEE13
Yu-Jing
U1
HVLED805
STMicroelectronics
Doc ID 018586 Rev 2
Note
AN3360
Figure 4.
Test board design and evaluation
PCB top side and through hole components
MM
MM
MM
!-V
Figure 5.
PCB bottom side and SMD components
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Transformer specification
AN3360
2
Transformer specification
Figure 6.
EEE13-11 vertical type for under 10 W
Table 3.
Transformer specification
Core spec-EEE13
Ae
36.7 mm2
Le
27 mm
AW
2.5 mm*4.8 mm
Wiring spec. for flyback 16 V output
Note:
Start
Finish
Wire
Winding
Turns
Inductance
LK inductance
L1
3
1
0.2 Φ*1C
Primary
72
1.9 mH±10%
31 µH ref.
L2
9
7
0.35 Φ*1C
Secondary
15
96 µH±10%
L3
4
5
0.2 Φ*1C
AUX
20
85 µH ref.
Class B insulation system: SB14.2
●
●
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No.
With standing voltage:
–
1.0 kV/1 sec/AC/5 mA, primary to secondary
–
0.5 kV/1 sec/AC/3 mA, primary to core
–
1.0 kV/1 sec/AC/3 mA, secondary to core
Manufacturer:
–
Yu-Jing Technology Co., LTD www.yujingtech.com.tw
–
Inductor P/N: 11999-310V600110 (EEE13-11V)
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AN3360
3
Efficiency measurements
Efficiency measurements
The efficiency of the converter has been measured in different load and line voltage
conditions.
The efficiency measurements have been done at 12 to 16 VDC of the rated output power, at
both 115 VAC and 230 VAC.
Table 4 and 5 show the results.
Table 4.
Efficiency at 115 VAC
VAC
Pin (W)
Vout (V)
Iout (mA)
Eff (%)
115
2.972
12.016
196.00
79.24
3.190
13.008
196.00
79.92
3.420
14.016
196.00
80.33
3.644
15.008
195.00
80.31
3.877
16.016
195.00
80.56
Average eff. (%)
Table 5.
80.07
Efficiency at 230 VAC
VAC
Pin (W)
Vout (V)
Iout (mA)
Eff (%)
230
3.238
12.016
195.00
72.36
3.500
13.008
200.00
74.33
3.792
14.016
204.00
75.40
4.050
15.008
204.00
75.60
4.262
16.016
204.00
76.66
Average eff. (%)
Figure 7.
74.87
Output characteristics
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Typical board waveforms
4
AN3360
Typical board waveforms
Drain voltage and current waveforms were reported for the two nominal input voltages and
for the minimum and the maximum voltage of the converter input operating range. Figure 8
and 9 show the drain current and the drain voltage waveforms at the nominal input voltages
and full load.
At low load OC enters into burst mode, reducing the switching frequency down to a
minimum fixed value; Figure 10 and 11 show the typical waveforms during no load
conditions at both 115 VAC and 230 VAC circuits at nominal input voltage.
The CC mode technique eliminates the need for overload protection; in fact, the maximum
output power is achieved on the corner point between CV mode and CC mode and
coincides with the full load condition. Figure 12 and 13 show the typical waveforms during
short-circuit at nominal input voltage.
Figure 14 and 15 show the startup in full load conditions and nominal input voltage; the
maximum drain-source voltage is well below the BVDSS of the IC.
Figure 8.
10/16
Normal operation at full load - at
115 VAC
Figure 9.
Doc ID 018586 Rev 2
Normal operation at full load - at
230 VAC
AN3360
Typical board waveforms
Figure 10. Normal operation at no load at 115 VAC
Figure 11. Normal operation at no load at 230 VAC
Figure 12. Short-circuit at 115 VAC
Figure 13. Short-circuit at 230 VAC
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Typical board waveforms
AN3360
Figure 14. Startup at full load at 115 VAC
12/16
Figure 15. Startup at full load at 230 VAC
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AN3360
5
Conclusion
Conclusion
The LED power supply demonstration board using the HVLED805 device was presented
and the results show that good performances can be obtained using this new device.
Auxiliary winding is required in the transformer to correctly perform CV/CC regulation, and
the chip is able to power itself directly from the rectified mains. This is particularly useful
during CC regulation, where the flyback voltage generated by the winding drops.
The HVLED805 is able to meet the most restrictive worldwide standards regarding
efficiency. The embedded onboard protections and the 800 V power section considerably
increase the end-product safety and reliability.
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References
6
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AN3360
References
1.
HVLED805 datasheet
2.
AN3093 application note
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AN3360
7
Revision history
Revision history
Table 6.
Document revision history
Date
Revision
Changes
30-Mar-2011
1
Initial release.
21-Jul-2011
2
– Updated Figure 3.
– Updated component D1 in Table 2.
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AN3360
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