Electronic Components Datasheet Search
  English  ▼

X  

Preview PDF HTML

RT9911 Datasheet(PDF) 28 Page - Richtek Technology Corporation

Part # RT9911
Description  6 Channel DC/DC Converters
PDF  32 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  RICHTEK [Richtek Technology Corporation]
Direct Link  http://www.richtek.com
Logo RICHTEK - Richtek Technology Corporation

RT9911 Datasheet(HTML) 28 Page - Richtek Technology Corporation

Back Button RT9911 Datasheet HTML 24Page - Richtek Technology Corporation RT9911 Datasheet HTML 25Page - Richtek Technology Corporation RT9911 Datasheet HTML 26Page - Richtek Technology Corporation RT9911 Datasheet HTML 27Page - Richtek Technology Corporation RT9911 Datasheet HTML 28Page - Richtek Technology Corporation RT9911 Datasheet HTML 29Page - Richtek Technology Corporation RT9911 Datasheet HTML 30Page - Richtek Technology Corporation RT9911 Datasheet HTML 31Page - Richtek Technology Corporation RT9911 Datasheet HTML 32Page - Richtek Technology Corporation  
Zoom Inzoom in Zoom Outzoom out
 28 / 32 page
background image
RT9911
28
DS9911-04 August 2007
www.richtek.com
Asyn-boost in CCM :
We call it CCM because inductor current is always
continuous in operation. The benefit of designing in CCM
is lower VOUT and inductor current ripple and higher
efficiency from the lower coil loss, but with the expense
of larger inductor size and cost and the control loop comes
with a RHPZ (Right Hand Plan Zero) and a conjugate double
pole in the frequency domain to worry about.
The fixed parameters for CH4 asyn-boost in CCM
compensation are as follows :
Transconductance (from FB to COMP), GM = 200us
Internal voltage ramp to decide duty cycle, VP = 1V
Feedback voltage, VFB = FB = 1V
The input parameters for CH4 asyn-boost in CCM
compensation are as follows:
R1, the voltage divider resistor in between VOUT and
FB.
VIN, input voltage.
VOUT, desired output voltage
IOUT(MAX.), maximum output load
IOUT(MIN.), minimum output laod
fOSC, operating frequency
The input parameters for CH4 asyn-boost in DCM
compensation are as follows :
R1, the voltage divider resistor in between VOUT and
FB.
VIN, input voltage.
VOUT, desired output voltage
IOUT(MAX.), maximum output load
fOSC, operating frequency
L, inductance
COUT, output capacitance. This compensation is based
on ceramic output capacitor.
RESR, ESR (Equivalent Series Resistance) of COUT
(ceramic output capacitor)
The results we will get for CH4 asyn-boost in DCM
compensation are as follows :
R2, the voltage divider resistor in between FB and ground.
CF, feedforward capacitor in parallel with R1.
RC, compensation resistor on COMP pin.
CC, compensation capacitor in series with RC and
connect to ground
CP, connect in between COMP pin and ground. (Can be
ignored if CP < 10pF)
The major steps for getting above results :
1.
2. Select suitable inductor to ensure IOUT(MIN.) works in
DCM, which is let inductor current falls to zero on each
switch cycle.
3. Set fC sufficient below fOSC.
For example:
4.
5.
which is duty to VOUT transfer function.
6.
7. Find ffz, zero and ffp, pole ratio of voltage divider with
CF.
8. Get CF by placing ffp on fC and ffz therefore on
.
9. Evaluate CP. CP is for canceling the zero from COUT
(ceramic output capacitor).
FB
OUT
FB
V
-
V
V
x
R1
R2
=
OSC
OUT(MAX.)
IN
f
x
I
x
2
D)
-
(1
x
D
x
V
L
<
lower
or
10
f
f
OSC
C
=
.
I
V
R
,
V
V
M
where
,
C
x
R
x
1)
-
(M
x
2
1
-
M
x
2
f
:
pole
load
the
Find
OUT(MAX.)
OUT
LOAD
IN
OUT
OUT
LOAD
LP
=
=
=
π
,
1
-
M
x
2
1
-
M
x
D
V
x
2
G
where
,
G
x
GM
x V
f
f
R
Get
OUT
dod
dod
P
LP
C
C
=
=
OUT
IN
V
V
-
1
cycle
duty
D
=
=
pole.
load
zero
comp
letting
by
R
R
x
C
C
Get
C
LOAD
OUT
C
=
=
FB
OUT
V
V
ffz
ffp
ratio
=
=
ratio
fC
10pF.
C
if
ignore
be
can
C
.
R
R
x
C
C
P
P
C
ESR
OUT
P
<
=
.
ratio
f
ff
where
,
R1
ff
2
1
C
C
Z
Z
F
=
×
×
=
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


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