Moteur de recherche de fiches techniques de composants électroniques
  French  ▼
ALLDATASHEET.FR

X  

CS5211 Fiches technique(PDF) 6 Page - ON Semiconductor

No de pièce CS5211
Description  Low Voltage Synchronous Buck Controller
Download  13 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Fabricant  ONSEMI [ON Semiconductor]
Site Internet  http://www.onsemi.com
Logo ONSEMI - ON Semiconductor

CS5211 Fiches technique(HTML) 6 Page - ON Semiconductor

Back Button CS5211 Datasheet HTML 2Page - ON Semiconductor CS5211 Datasheet HTML 3Page - ON Semiconductor CS5211 Datasheet HTML 4Page - ON Semiconductor CS5211 Datasheet HTML 5Page - ON Semiconductor CS5211 Datasheet HTML 6Page - ON Semiconductor CS5211 Datasheet HTML 7Page - ON Semiconductor CS5211 Datasheet HTML 8Page - ON Semiconductor CS5211 Datasheet HTML 9Page - ON Semiconductor CS5211 Datasheet HTML 10Page - ON Semiconductor Next Button
Zoom Inzoom in Zoom Outzoom out
 6 / 13 page
background image
CS5211
http://onsemi.com
6
THEORY OF OPERATION
V2 Control Method
The V2 method of control uses a ramp signal that is
generated by the ESR of the output capacitors. This ramp is
proportional to the AC current through the main inductor
and is offset by the value of the DC output voltage. This
control scheme inherently compensates for variations in
either line or load conditions, since the ramp signal is
generated from the output voltage itself. This control
scheme differs from traditional techniques such as voltage
mode, which generates an artificial ramp, and current mode,
which generates a ramp from inductor current.
Ramp Signal
Error Signal
Error Amplifier
COMP
GATE(L)
GATE(H)
Output
Voltage
Feedback
PWM Comparator
Figure 3. V2 Control Block Diagram
Reference
Voltage
The V2 control method is illustrated in Figure 3. The
output voltage is used to generate both the error signal and
the ramp signal. Since the ramp signal is simply the output
voltage, it is affected by any change in the output regardless
of the origin of the change. The ramp signal also contains the
DC portion of the output voltage, which allows the control
circuit to drive the main switch to 0% or 100% duty cycle as
required.
A change in line voltage changes the current ramp in the
inductor, affecting the ramp signal, which causes the V2
control scheme to compensate the duty cycle. Since the
change in the inductor current modifies the ramp signal, as
in current mode control, the V2 control scheme has the same
advantages in line transient response.
A change in load current will have an effect on the output
voltage, altering the ramp signal. A load step immediately
changes the state of the comparator output, which controls
the main switch. Load transient response is determined only
by the comparator response time and the transition speed of
the main switch. The reaction time to an output load step has
no relation to the crossover frequency of the error signal
loop, as in traditional control methods.
The error signal loop can have a low crossover frequency,
since transient response is handled by the ramp signal loop.
The main purpose of this “slow” feedback loop is to provide
DC accuracy. Noise immunity is significantly improved,
since the error amplifier bandwidth can be rolled off at a low
frequency. Enhanced noise immunity improves remote
sensing of the output voltage, since the noise associated with
long feedback traces can be effectively filtered.
Line and load regulations are drastically improved
because there are two independent voltage loops. A voltage
mode controller relies on a change in the error signal to
compensate for a deviation in either line or load voltage.
This change in the error signal causes the output voltage to
change corresponding to the gain of the error amplifier,
which is normally specified as line and load regulation. A
current mode controller maintains fixed error signal under
deviation in the line voltage, since the slope of the ramp
signal changes, but still relies on a change in the error signal
for a deviation in load. The V2 method of control maintains
a fixed error signal for both line and load variations, since
both line and load affect the ramp signal.
Constant Frequency Operation
The CS5211 uses a constant frequency, trailing edge
modulation architecture for generating PWM signal. During
normal operation, the oscillator generates a narrow pulse at
the beginning of each switching cycle to turn on the main
switch. The main switch will be turned off when the ramp
signal intersects with the output of the error amplifier
(COMP pin voltage). Therefore, the switch duty cycle can
be modified to regulate the output voltage to the desired
value as line and load conditions change.
The major advantage of constant frequency operation is
that the component selections, especially the magnetic
component design, become very easy. The oscillator
frequency of CS5211 is programmable from 150 kHz to
750 kHz using an external resistor connected from the ROSC
pin to ground.
Startup
If there are no fault conditions and the fault latch is reset,
the error amplifier will start charging the COMP pin
capacitor after the CS5211 is powered up. The output of the
error amplifier (COMP voltage) will ramp up linearly. The
COMP capacitance and the source current of the error
amplifier determine the slew rate of COMP voltage. The
output of the error amplifier is connected internally to the
inverting input of the PWM comparator and it is compared
with the VFFB pin voltage plus 0.5 V offset at the
non−inverting input of the PWM comparator. Since VFFB
voltage is zero before the startup, the PWM comparator
output will stay high until the COMP pin voltage hits 0.5 V.
There is no switching action while the PWM comparator
output is high.
After the COMP voltage exceeds the 0.5 V offset, the
output of PWM comparator toggles and releases the PWM
latch. The narrow pulse generated by the oscillator at the
beginning of the next oscillator cycle will set the latch so that
the main switch can be turned on and the regulator output
voltage ramps up. When the output voltage achieves a level
set by the COMP voltage, the main switch will be turned off.
The V2 control loop will adjust the main switch duty cycle
as required to ensure the regulator output voltage tracks the


Numéro de pièce similaire - CS5211

FabricantNo de pièceFiches techniqueDescription
logo
ON Semiconductor
CS5211 ONSEMI-CS5211 Datasheet
105Kb / 16P
   Low Voltage Synchronous Buck Controller
December, 2001 ??Rev. 4
CS5211 ONSEMI-CS5211 Datasheet
3Mb / 4P
   AC-DC Offline Switching Controllers/Regulators
Rev.0, Jun-2005
CS5211ED14 ONSEMI-CS5211ED14 Datasheet
105Kb / 16P
   Low Voltage Synchronous Buck Controller
December, 2001 ??Rev. 4
CS5211EDR14 ONSEMI-CS5211EDR14 Datasheet
105Kb / 16P
   Low Voltage Synchronous Buck Controller
December, 2001 ??Rev. 4
CS5211GD14 ONSEMI-CS5211GD14 Datasheet
105Kb / 16P
   Low Voltage Synchronous Buck Controller
December, 2001 ??Rev. 4
More results

Description similaire - CS5211

FabricantNo de pièceFiches techniqueDescription
logo
ON Semiconductor
CS5212 ONSEMI-CS5212_06 Datasheet
321Kb / 13P
   Low Voltage Synchronous Buck Controller
July, 2006 ??Rev. 4
NCP1586 ONSEMI-NCP1586 Datasheet
80Kb / 8P
   Low Voltage Synchronous Buck Controller
March, 2007 ??Rev. 0
NCP1570 ONSEMI-NCP1570 Datasheet
279Kb / 14P
   Low Voltage Synchronous Buck Controller
July, 2006 ??Rev. 5
logo
Unisonic Technologies
UCS1201 UTC-UCS1201 Datasheet
166Kb / 5P
   LOW VOLTAGE SYNCHRONOUS BUCK CONTROLLER
logo
ON Semiconductor
NCP1589D ONSEMI-NCP1589D_17 Datasheet
89Kb / 8P
   Low Voltage Synchronous Buck Controller
January, 2017 ??Rev. 2
NCP81046 ONSEMI-NCP81046 Datasheet
157Kb / 10P
   Low Voltage Synchronous Buck Controller
June, 2012 ??Rev. P0
NCP1579 ONSEMI-NCP1579_13 Datasheet
148Kb / 11P
   Low Voltage Synchronous Buck Controller
April, 2013 ??Rev. 3
NCP1588 ONSEMI-NCP1588_V01 Datasheet
199Kb / 12P
   Low Voltage Synchronous Buck Controller
January, 2008 - Rev. 4
NCP1589A ONSEMI-NCP1589A Datasheet
206Kb / 10P
   Low Voltage Synchronous Buck Controller
May, 2009 ??Rev. P4
NCP1571 ONSEMI-NCP1571 Datasheet
104Kb / 16P
   Low Voltage Synchronous Buck Controller
October, 2004 ??Rev. 4
logo
Texas Instruments
UCC3585M TI1-UCC3585M Datasheet
802Kb / 21P
[Old version datasheet]   LOW-VOLTAGE SYNCHRONOUS BUCK CONTROLLER
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13


Fiches technique Télécharger

Go To PDF Page


Lien URL




Politique de confidentialité
ALLDATASHEET.FR
ALLDATASHEET vous a-t-il été utile ?  [ DONATE ] 

À propos de Alldatasheet   |   Publicité   |   Contactez-nous   |   Politique de confidentialité   |   Echange de liens   |   Fabricants
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