Data brief
For further information contact your local STMicroelectronics sales office.
February 2011 Doc ID 010004 Rev 1 1/5
5
EVL6566B-65W-QR
19 V - 65 W quasi resonant flyback adapter board
Features
■Universal input mains range: 90 264 Vac -
frequency 45 ÷ 65Hz
■Output voltage: 19 V @ 3.42 A continuous
operation
■Mains harmonics: according to EN61000-3-2
Class-D or JEITA-MITI Class-D
■Stand-by mains consumption: <100 mW @
230 Vac
■Average efficiency: better than 89% without
synchronous rectification
■EMI: according to EN55022-Class-B
■Safety: according to EN60950
■Dimensions: 58x121 mm, 25 mm components
maximum height
■PCB: single side, 35 µm, CEM-1, mixed
PTH/SMT
Description
The EVL6566B-65W-QR is a demonstration
board tailored on specification of a typical hi-end
portable computer power supply. The peculiarities
of this design are the very high average efficiency
of about 90% without synchronous rectification
and very low no load consumption of 100mW at
230 Vac. The result is that this converter is
compliant to energy star eligibility criteria. The
flyback stage implements the new ST dedicated
current mode controller L6566B, operating in
quasi-resonant mode and detecting the
transformer demagnetization by pin ZCD.
The resistor on pin OSC sets the maximum
switching frequency at about 165 kHz.
Because the maximum switching frequency is
imposed, the converter operates in discontinuous
conduction mode during light load operation. The
L6566B valley skipping function is capable to
turn-on the MOSFET in valley switching even in
DCM, thus reducing switching losses.
The Power MOSFET is a standard 800 V,
STF7NM80, housed in TO-220FP package,
needing just a small heat sink. The transformer is
layer type, using a standard ferrite size EER28L,
designed according to the EN60950.
The flyback reflected voltage is ~150 V, providing
enough room for the leakage inductance voltage
spike with good margin for the reliability of the
MOSFET.
The output rectifiers are two, dual centre tap
Schottky diode in parallel, STPS20H100CFP,
housed in TO-220FP. They have been selected
according to the maximum reverse voltage,
forward voltage drop and power dissipation. The
snubber damps the oscillation produced by the
diode capacitance and the leakage inductance.
A small LC filter has been added on the output,
filtering the high frequency ripple and spikes.
Thanks to the L6566B valley skipping feature it
has been possible to dimension the power
transformer parameters optimizing efficiency at
different loads achieving an outstanding result
even without synchronous rectification.
www.st.com
Electrical diagram and efficiency EVL6566B-65W-QR
2/5 Doc ID 010004 Rev 1
1 Electrical diagram and efficiency
Figure 1. Electrical diagram
6 !
6AC
#
.
#
.
*
-+$3
*
-+$3
#
U6
#
U6
4
4
2
+
2
+
,
,
#
U6
#
U6
2
+
2
+
$
,,
$
,,
*
-+$3
*
-+$3
$
3403(#&0
$
3403(#&0
#
P&
#
P&
2
+
2
+
2
+
2
+
#
U6
#
U6
&
4%!
&
4%!
2
+
2
+
$
3-
$
3-
#
.
#
.
.#
'.$
'$
6##
&-/$
$)3
#/-0
!#?/+
#3
-/$%3#
/3#
33
6&&
62%&
:#$
(6
5
,"
5
,"
?
^
^
$
'"5*
?
^
^
$
'"5*
2
+
2
+
#
.
#
.
5
3&(!
5
3&(!
2
+
2
+
#
.
#
.
#
P&
#
P&
1
"##
1
"##
2
+
2
+
#
.
#
.
2
2
2
2
2
-
2
-
#
.
#
.
#
.
#
.
2
+
2
+
2
+
2
+
2
+
2
+
#
P&
#
P&
$
":6"
$
":6"
#
.
#
.
#
.
#
.
#6?/54
#6
6?2%&
'.$
##
##
##?/54
6##
5
43-!)34
5
43-!)34
$
+%!
$
+%!
2
2
2
2
2
2
2
2
#
.
#
.
2
+
2
+
2
+
2
+
2
+
2
+
2
2
2
2
2
+
2
+
2
+
2
+
2
2
2
2
2
2
2
2
$
3-
$
3-
2
+
2
+
#
U6
#
U6
#
.
#
.
2
+
2
+
#
.
#
.
1
"##
1
"##
2
+
2
+
2
+
2
+
#
.
#
.
2
+
2
+ 2
+
2
+
2
+
2
+
#
.
#
.
2
+
2
+
$
3-
$
3-
2
-
2
-
$
344(!
$
344(!
2
+
2
+
#
.
#
.
2
.4#23
2
.4#23
2
.-
2
.-
2
2
2
2
2
+
2
+
2
-
2
-
2
2
2
2
1
"##
1
"##
#
.
#
.
#
P&K6
#
P&K6
#
U&6
#
U&6
#
.
#
.
(3
(%!43).+
(3
(%!43).+
,
(&924
,
(&924
#
U6
#
U6
(3
(%!43).+
(3
(%!43).+
$
,,
$
,,
1
34&.-
1
34&.-
$
3403(#&0
$
3403(#&0
!-6
EVL6566B-65W-QR Electrical diagram and efficiency
Doc ID 010004 Rev 1 3/5
Table 1. Overall efficiency and no load consumption
Test
230 V-50 Hz 115 V-60 Hz
Vout
[V]
Iout
[mA]
Pout
[W]
Pin
[W]
Eff.
[%]
Vout
[V]
Iout
[A]
Pout
[W]
Pin
[W]
Eff.
[%]
No load 19.00 0.00 0.00 94mW - 19.00 0.00 0.00 75mW -
25% load eff. 18.97 0.86 16.37 18.53 88.3 18.97 0.86 16.32 18.03 90.5
50% load eff. 18.97 1.71 32.50 35.77 90.9 18.97 1.72 32.54 35.91 90.6
75% load eff. 18.98 2.57 48.74 53.44 91.2 18.97 2.57 48.82 54.39 89.8
100% load eff. 18.98 3.42 64.89 71.18 91.2 18.98 3.42 64.99 73.30 88.7
Average eff. 90.4 89.9
Revision history EVL6566B-65W-QR
4/5 Doc ID 010004 Rev 1
2 Revision history
Table 2. Document revision history
Date Revision Changes
21-Feb-2011 1 Initial release.
EVL6566B-65W-QR
Doc ID 010004 Rev 1 5/5
Please Read Carefully:
Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the
right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any
time, without notice.
All ST products are sold pursuant to ST’s terms and conditions of sale.
Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no
liability whatsoever relating to the choice, selection or use of the ST products and services described herein.
No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted under this document. If any part of this
document refers to any third party products or services it shall not be deemed a license grant by ST for the use of such third party products
or services, or any intellectual property contained therein or considered as a warranty covering the use in any manner whatsoever of such
third party products or services or any intellectual property contained therein.
UNLESS OTHERWISE SET FORTH IN ST’S TERMS AND CONDITIONS OF SALE ST DISCLAIMS ANY EXPRESS OR IMPLIED
WARRANTY WITH RESPECT TO THE USE AND/OR SALE OF ST PRODUCTS INCLUDING WITHOUT LIMITATION IMPLIED
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS
OF ANY JURISDICTION), OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT.
UNLESS EXPRESSLY APPROVED IN WRITING BY AN AUTHORIZED ST REPRESENTATIVE, ST PRODUCTS ARE NOT
RECOMMENDED, AUTHORIZED OR WARRANTED FOR USE IN MILITARY, AIR CRAFT, SPACE, LIFE SAVING, OR LIFE SUSTAINING
APPLICATIONS, NOR IN PRODUCTS OR SYSTEMS WHERE FAILURE OR MALFUNCTION MAY RESULT IN PERSONAL INJURY,
DEATH, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE. ST PRODUCTS WHICH ARE NOT SPECIFIED AS "AUTOMOTIVE
GRADE" MAY ONLY BE USED IN AUTOMOTIVE APPLICATIONS AT USER’S OWN RISK.
Resale of ST products with provisions different from the statements and/or technical features set forth in this document shall immediately void
any warranty granted by ST for the ST product or service described herein and shall not create or extend in any manner whatsoever, any
liability of ST.
ST and the ST logo are trademarks or registered trademarks of ST in various countries.
Information in this document supersedes and replaces all information previously supplied.
The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners.
© 2011 STMicroelectronics - All rights reserved
STMicroelectronics group of companies
Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan -
Malaysia - Malta - Morocco - Philippines - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America
www.st.com
