Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.NET

X  

Preview PDF HTML

AN2870 Datasheet(PDF) 27 Page - STMicroelectronics

Part # AN2870
Description  L6585DE combo IC
PDF  41 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  STMICROELECTRONICS [STMicroelectronics]
Direct Link  http://www.st.com
Logo STMICROELECTRONICS - STMicroelectronics

AN2870 Datasheet(HTML) 27 Page - STMicroelectronics

Back Button AN2870 Datasheet HTML 23Page - STMicroelectronics AN2870 Datasheet HTML 24Page - STMicroelectronics AN2870 Datasheet HTML 25Page - STMicroelectronics AN2870 Datasheet HTML 26Page - STMicroelectronics AN2870 Datasheet HTML 27Page - STMicroelectronics AN2870 Datasheet HTML 28Page - STMicroelectronics AN2870 Datasheet HTML 29Page - STMicroelectronics AN2870 Datasheet HTML 30Page - STMicroelectronics AN2870 Datasheet HTML 31Page - STMicroelectronics Next Button
Zoom Inzoom in Zoom Outzoom out
 27 / 41 page
background image
AN2870
Designing with L6585DE
27/41
Where Rout is the effective resistance of the load (i.e. VOUT
2/P
OUT), kM is the multiplier gain
(reported in datasheet) and Cout is the bulk capacitor.
In order to compensate the loop and reject the ripple superimposed to the output voltage,
the loop gain at 100 Hz should be less than -60 dB. The transfer function of the error
amplifier, compensated with a simple capacitor can be written as:
Equation 25
and:
Equation 26
Using a high value for
Rinvh the value of Ccomp is reduced.
Input rectifier
This component is needed to supply the PFC stage with a rectified voltage.
The reverse voltage should be greater than twice Vin,max, the forward current greater than
maximum input current and the power dissipation greater than:
Equation 27
Input capacitor
At this stage of design the current absorption is impulsive. The mean value of this current is
in phase with the input voltage, but the high frequency components have amplitude equal to
twice the amplitude of the mean value, therefore can create interferences with nearby
electronic equipment. An input filter capacitor must be placed between the rectifier and the
PFC stage in order to reduce the high frequency current ripple superimposed to the input
current.
Let be r the maximum allowed ratio between ripple amplitude and mean value of the input
current:
Equation 28
()
invh
comp
comp
R
sC
1
s
G
=
()
()
()
001
.
0
2
C
R
s
1
1
R
R
V
V
k
k
4
1
R
sC
1
s
G
s
G
s
G
Hz
100
2
s
out
out
pfccs
out
out
2
rms
,
in
p
M
invh
comp
comp
loop
=
⎟
⎟
⎟
⎟
⎠
⎞
⎜
⎜
⎜
⎜
⎝
⎛
+
⋅
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
=
⋅
=
π
=
F
(min)
rms
,
in
in
F
(max)
rms
,
in
B
V
V
P
2
2
V
I
2
4
P
=
=
2
(min)
RMS
,
in
sw
in
(min)
RMS
,
in
min
sw
RMS
,
in
min
,
in
V
f
r
2
P
V
f
r
2
I
C
min
⋅
⋅
⋅
π
=
⋅
⋅
⋅
π
=



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


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