数据搜索系统，热门电子元器件搜索
  Chinese  ▼
ALLDATASHEETCN.COM

X  

预览 PDF HTML

AN4149 数据表(PDF) 7 Page - STMicroelectronics

部件名 AN4149
功能描述  Designing a CCM PFC pre-regulator based on the L4984D
PDF  43 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
制造商  STMICROELECTRONICS [STMicroelectronics]
网页  http://www.st.com
标志 STMICROELECTRONICS - STMicroelectronics

AN4149 数据表(HTML) 7 Page - STMicroelectronics

Back Button AN4149 Datasheet HTML 3Page - STMicroelectronics AN4149 Datasheet HTML 4Page - STMicroelectronics AN4149 Datasheet HTML 5Page - STMicroelectronics AN4149 Datasheet HTML 6Page - STMicroelectronics AN4149 Datasheet HTML 7Page - STMicroelectronics AN4149 Datasheet HTML 8Page - STMicroelectronics AN4149 Datasheet HTML 9Page - STMicroelectronics AN4149 Datasheet HTML 10Page - STMicroelectronics AN4149 Datasheet HTML 11Page - STMicroelectronics Next Button
Zoom Inzoom in Zoom Outzoom out
 7 / 43 page
background image
DocID023523 Rev 2
7/43
AN4149
CCM PFC using FOT control
and the switching frequency will be:
Equation 7
The timing capacitor CT, therefore, will be selected with the following design formula:
Equation 8
Vout and fsw are design specifications, KP is chosen so that the voltage on pin MULT is
within the multiplier's linearity range (0 to 3 V) and ITIMER is specified in the "Electrical
characteristics" section of the L4984D datasheet.
Along a line half-cycle, TOFF goes all the way from nearly zero to the maximum on the
sinusoid peak. It is important to check that the OFF-time occurring on the peak of the
sinusoidal voltage at minimum input voltage is greater than the minimum programmable
value:
Equation 9
This constraint limits the maximum programmable frequency at:
Equation 10
As the line RMS voltage is increased and/or the output load is decreased the boost inductor
current tends to become discontinuous starting from the region around the zero-crossings.
As a result, in the DCM regions the switching frequency is no longer constant and tends to
increase.
Figure 6. Boundary between DCM and CCM
Vout
K
Vout
C
K
I
T
f
t
T
P
TIMER
sw
sw
1
1
=
=
=
sw
P
TIMER
T
f
Vout
K
I
C
=
s
1.2
μ
>
=
min
P
TIMER
T
min
OFF
Vpk
K
I
C
T
Vout
Vpk
f
min
max
.
sw
833
=
[]
KHz
AM13305v1



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 40 41 42 43


数据表 下载

Go To PDF Page


链接网址



ALLDATASHEET是否为您带来帮助?  [ DONATE ] 

关于 Alldatasheet   |   广告服务   |   联系我们   |   隐私政策   |   数据表链接    |   链接交换   |   制造商名单
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