Electronic Components Datasheet Search
  New Zealand  ▼
ALLDATASHEET.CO.NZ

X  

Preview PDF HTML

AN2782 Datasheet(PDF) 9 Page - STMicroelectronics

Part # AN2782
Description  Solution for designing a 400 W fixed-off-time controlled
PDF  39 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  STMICROELECTRONICS [STMicroelectronics]
Direct Link  http://www.st.com
Logo STMICROELECTRONICS - STMicroelectronics

AN2782 Datasheet(HTML) 9 Page - STMicroelectronics

Back Button AN2782 Datasheet HTML 5Page - STMicroelectronics AN2782 Datasheet HTML 6Page - STMicroelectronics AN2782 Datasheet HTML 7Page - STMicroelectronics AN2782 Datasheet HTML 8Page - STMicroelectronics AN2782 Datasheet HTML 9Page - STMicroelectronics AN2782 Datasheet HTML 10Page - STMicroelectronics AN2782 Datasheet HTML 11Page - STMicroelectronics AN2782 Datasheet HTML 12Page - STMicroelectronics AN2782 Datasheet HTML 13Page - STMicroelectronics Next Button
Zoom Inzoom in Zoom Outzoom out
 9 / 39 page
background image
AN2782
Designing a fixed off-time PFC
Doc ID 14763 Rev 2
9/39
4
Designing a fixed off-time PFC
4.1
Input specification
The following is a possible design flowchart in reference to a fixed off-time mode PFC using
the L6562A. This first part is a detailed specification of the operating conditions of the circuit
that is needed for the following calculations in Section 4.2. In this example a 400 W, wide
input range mains PFC circuit has been considered. Some design criteria are also given.
Because the PFC is a boost topology the regulated output voltage depends strongly on the
maximum AC input voltage. In fact, for correct boost operation the output voltage must
always be higher than the input and thus, because Vin max is
Vpk, the
output has been set at 400 Vdc as the typical value. If the input voltage is higher, as typical
in ballast applications, the output voltage must be set higher accordingly. As a rule of thumb
the output voltage must be set 6/7% higher than the maximum input voltage peak.
The target efficiency and PF are set here at minimum input voltage and maximum load.
They are used for the following operating condition calculation of the PFC. Of course at high
input voltage the efficiency is higher.
Because of the narrow loop voltage bandwidth, the PFC output can face overvoltages at
startup or in case of load transients. To protect from excessive output voltage that can
overstress the output components and the load, the L6562A integrates an OVP. The
overvoltage protection sets the extra voltage overimposed to Vout:
●
Mains voltage range (Vac rms):
(8)
●
Minimum mains frequency:
(9)
●
Rated output power (W):
(10)
●
Regulated DC output voltage (Vdc):
(11)
●
Expected efficiency (%):
(12)
●
Expected power factor:
(13)
●
Maximum output overvoltage (Vdc):
(14)
Vac
90
VACmin =
Vac
265
VACmax =
Hz
47
fl =
W
400
Pout =
VAC
max
2
374
=
⋅
V
400
V
out =
%
90
P
P
in
out
=
=
η
99
.
0
PF
=
V
40
OVP
=
Δ



Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39


Datasheet Download

Go To PDF Page


Link URL



Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Link to Datasheet    |   Link Exchange   |   Manufacturer List
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com