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.
STEVAL-ILL037V1 demonstration board image
July 2011
Doc ID 018586 Rev 2
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www.st.com
Contents
AN3360
Contents
1
2
3
4
5
6
7
Test board design and evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Transformer specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Efficiency measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Typical board waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
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Doc ID 018586 Rev 2
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 V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Normal operation at full load - at 230 V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Normal operation at no load - at 115 V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Normal operation at no load - at 230 V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Short-circuit at 115 V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Short-circuit at 230 V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Startup at full load at 115 V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Startup at full load at 230 V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Doc ID 018586 Rev 2
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Test board design and evaluation
AN3360
1
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.
STEVAL-ILL037V1 demonstration board: electrical specifications
Parameter
Input voltage range (V
IN
)
Mains frequency (f
L
)
Output power consumption
Output voltage
Output current
Target average efficiency
Value
90 - 265 V
AC
50 - 60 Hz
3.2 W
16 V
DC
(3~5 LEDs)
200 mA
>70%
Figure 2.
For E26/E27 application
4/16
Doc ID 018586 Rev 2
AN3360
Figure 3.
Electrical schematic
Test board design and evaluation
Doc ID 018586 Rev 2
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