AN3093
Application note
ALTAIR05T-800 5 W wide range CV-CC
optoless adapter demonstration board
1
Introduction
This application note describes the demonstration board of the all primary-sensing switching
regulator ALTAIR05T-800 and presents the results of its bench evaluation. The board
implements a 5 W (5 V / 1 A) wide range mains battery charger with constant
voltage/constant current.
The ALTAIR05T-800 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 is capable of providing constant output voltage (CV) and constant output current
(CC) regulation using primary sensing feedback. This eliminates the need for the
optocoupler, the secondary voltage reference, as well as the current sensor, while
maintaining very accurate regulation.
Additionally, it is possible to compensate the voltage drop of the output cable, so as to
improve CV regulation on the externally accessible terminals.
Extremely low consumption under no-load conditions is ensured thanks to a controlled burst
mode operation that, along with the built-in high-voltage startup circuit and the low operating
current of the device, helps minimize residual input consumption. Although an auxiliary
winding is required in the transformer to correctly perform CV/CC regulation, the chip is
capable of powering itself directly from the rectified mains. This is useful especially during
CC regulation, where the flyback voltage generated by the winding drops. However, if ultra
low no-load input consumption is required to comply with the most stringent energy saving
recommendations, then the device needs to be powered via the auxiliary winding.
Figure 1.
Demonstration board picture
January 2011
Doc ID16539 Rev 1
1/29
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Contents
AN3093
Contents
1
2
3
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Test board: design and evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Efficiency and no-load measurements . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.1
3.2
Standby optimization: tips for reducing standby consumption . . . . . . . . . 12
Design optimization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Five star charger energy rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4
5
6
Typical board waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
V-I output characteristics and cable drop compensation . . . . . . . . . . 19
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Appendix A Modes of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
A.1
A.2
A.3
A.4
Constant voltage operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Constant current operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Current comparator speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Cable drop compensation block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
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AN3093
List of tables
List of tables
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
Table 7.
ALTAIR05T-800 demonstration board: electrical specification . . . . . . . . . . . . . . . . . . . . . . . 5
ALTAIR05T-800 demonstration board: bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
ALTAIR05T-800 demonstration board: transformer characteristics . . . . . . . . . . . . . . . . . . . 9
Efficiency at 115 V
AC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Efficiency at 230 V
AC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Standby consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
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List of figures
AN3093
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.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
Figure 21.
Figure 22.
Figure 23.
Figure 24.
Figure 25.
Demonstration board picture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Electrical schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
PCB: top side and through-hole components
(1)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
PCB: bottom side and SMD components
(1)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Electrical schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Side view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Bottom side view. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
PCB hole dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Efficiency vs. output power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
No-load consumption score chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Normal operation at full load, at 115 V
AC
and 230 V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Normal operation in CC mode with V
OUT
= 3 V, at 115 V
AC
and 230 V
AC
. . . . . . . . . . . . . 16
Short-circuit at 115 V
AC
and 230 V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Normal operation at no-load, at 115 V
AC
and 230 V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Startup at no-load, at 115 V
AC
and 230 V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Startup at full load, at 115 V
AC
and 230 V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Output characteristic at 115 V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Output characteristic at 230 V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Output characteristic without cable drop compensation: R
CABLE
= 0.32
Ω
and R
5
= 10 kΩ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Output characteristic with cable drop compensation: R
CABLE
= 0.32
Ω
and R
5
= 10 kΩ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Voltage control principle: internal schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Current control principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Constant current operation: switching cycle waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Feed-forward compensation: internal schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
CDC compensation: external configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
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AN3093
Test board: design and evaluation
2
Test board: design and evaluation
A 5 W battery charger demonstration board based on ALTAIR05T-800 is now presented.
Table 1
summarizes the electrical specifications of the application.
Table 2
provides the bill
of materials and
Table 3
lists the transformer specifications. The electrical schematic is
shown in
Figure 2
and the PCB layout in
Figure 3
and
Figure 4.
Table 1.
ALTAIR05T-800 demonstration board: electrical specification
Parameter
Input voltage range (V
IN
)
Mains frequency (f
L
)
Maximum (rated) output power
Output
Minimum switching frequency in normal mode
Target average efficiency (at P
OUT
= 5 W, V
IN
= 90 - 264 V
AC
)
Maximum input power in standby
Value
90 - 265 V
AC
50 - 60 Hz
5W
V
OUT
= 5 V ± 5%
I
OUT
= 0 to 1 A ± 7%
V
ripple
< 100 mV
70 kHz
> 70%
(1)
< 100 mW
(2)
1. Compliant with the EPA 2.0 standard for low voltage devices (V
OUT
< 6, I
OUT
> 0.55 A).
2. Compliant with the European Code of Conduct, adapter for mobile handheld battery-driven applications,
starting from 1
st
January 2011.
Doc ID16539 Rev 1
5/29
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