Motor de Búsqueda de Datasheet de Componentes Electrónicos
  Spanish  ▼
ALLDATASHEET.ES

X  

FAN6520AM Datasheet(PDF) 8 Page - Fairchild Semiconductor

No. de pieza FAN6520AM
Descripción Electrónicos  Single Synchronous Buck PWM Controller
Download  15 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Fabricante Electrónico  FAIRCHILD [Fairchild Semiconductor]
Página de inicio  http://www.fairchildsemi.com
Logo FAIRCHILD - Fairchild Semiconductor

FAN6520AM Datasheet(HTML) 8 Page - Fairchild Semiconductor

Back Button FAN6520AM Datasheet HTML 4Page - Fairchild Semiconductor FAN6520AM Datasheet HTML 5Page - Fairchild Semiconductor FAN6520AM Datasheet HTML 6Page - Fairchild Semiconductor FAN6520AM Datasheet HTML 7Page - Fairchild Semiconductor FAN6520AM Datasheet HTML 8Page - Fairchild Semiconductor FAN6520AM Datasheet HTML 9Page - Fairchild Semiconductor FAN6520AM Datasheet HTML 10Page - Fairchild Semiconductor FAN6520AM Datasheet HTML 11Page - Fairchild Semiconductor FAN6520AM Datasheet HTML 12Page - Fairchild Semiconductor Next Button
Zoom Inzoom in Zoom Outzoom out
 8 / 15 page
background image
©2005 Fairchild Semiconductor Corporation
www.fairchildsemi.com
FAN6520A Rev. 1.0.5
8
Feedback Compensation
Figure 7 highlights the voltage-mode control loop for a
synchronous-rectified buck converter. The output voltage
(VOUT) is regulated to the reference voltage level. The
error amplifier (Error Amp) output (VE/A) is compared
with the oscillator (OSC) triangular wave to provide a
pulse-width modulated (PWM) wave with an amplitude of
VIN at the SW node. The PWM wave is smoothed by the
output LC filter (LOUT and COUT).
Figure 7. Voltage Mode Buck
Converter Compensation Design
The modulator transfer function is the small-signal trans-
fer function of VOUT/VCOMP. This function is dominated
by a DC gain and the output filter (LOUT and COUT), with
a double-pole break frequency at FLC and a zero at
FESR. The DC gain of the modulator is the input voltage
(VIN) divided by the peak-to-peak oscillator voltage
(
ΔV
OSC. )
The following equations define the modulator break fre-
quencies as a function of the output LC filter:
The compensation network consists of the error amplifier
(internal to the FAN6520A) and the impedance networks
ZIN and ZFB. The goal of the compensation network is to
provide a closed-loop transfer function with the highest
0dB crossing frequency (F0dB) and adequate phase mar-
gin. Phase margin is the difference between the closed-
loop phase at F0dB and 180 degrees. The equations
below relate the compensation network’s poles, zeros,
and gain to the components (R1, R2, R3, C1, C2, and
C3), shown in Figure 7.
Use the following steps to locate the poles and zeros of
the compensation network:
1.
Pick gain (R2/R1) for the desired converter band-
width.
2.
Place the first zero below the filter’s double pole
(~75% FLC).
3.
Place the second zero at filter’s double pole.
4.
Place the first pole at the ESR zero.
5.
Place the second pole at half the switching fre-
quency.
6.
Check the gain against the error amplifier’s open-
loop gain.
7.
Estimate phase margin. Repeat if necessary.
Figure 8 shows an asymptotic plot of the DC-DC con-
verter’s gain vs. frequency. The actual modulator gain
has a high gain peak due to the high Q factor of the out-
put filter and is not shown in Figure 8. Using the above
guidelines should give a compensation gain similar to
the curve plotted. The open-loop error amplifier gain
bounds the compensation gain. Check the compensation
gain at FP2 with the capabilities of the error amplifier.
The closed-loop gain is constructed on the graph of Fig-
ure 8 by adding the modulator gain (in dB) to the com-
pensation gain (in dB). This is equivalent to multiplying
the modulator transfer function by the compensation
transfer function and plotting the gain.
The compensation gain uses external impedance net-
works ZFB and ZIN to provide a stable high bandwidth
overall loop. A stable control loop has a gain crossing
with a –20dB/decade slope and a phase margin greater
than 45°. Include worst-case component variations when
determining phase margin.
ZFB
COMP
FB
+VOUT
Q2
LOUT
COUT
+5V
VIN
SW
0.8V
ERROR
AMP
PWM
OSC
DETAILED COMPENSATION
COMPONENTS
COMP
FB
0.8V
ERROR
AMP
C1
R2
C3
R3
C2
R1
Z
IN
V
OUT
ZFB
ZIN
F
LC
1
2
π LC
×
-------------------------
=
(3)
F
ESR
1
2
π ESR
×
C
×
------------------------------------
=
(4)
F
Z1
1
2
πR
2C1
----------------------
=
(5)
F
P1
1
2
πR
2
C
1C2
C
1
C
2
+
--------------------
⎝⎠
⎛⎞
-----------------------------------------
=
(6)
F
Z2
1
2
πC
3 R1
R
3
+
()
----------------------------------------
=
(7)
F
P2
1
2
πR
3C3
----------------------
=
(8)


Número de pieza similar - FAN6520AM

Fabricante ElectrónicoNo. de piezaDatasheetDescripción Electrónicos
logo
Fairchild Semiconductor
FAN6520AM FAIRCHILD-FAN6520AM Datasheet
580Kb / 15P
   Single Synchronous Buck PWM Controller
FAN6520AMX FAIRCHILD-FAN6520AMX Datasheet
580Kb / 15P
   Single Synchronous Buck PWM Controller
More results

Descripción similar - FAN6520AM

Fabricante ElectrónicoNo. de piezaDatasheetDescripción Electrónicos
logo
Taiwan Semiconductor Co...
TS3404 TSC-TS3404_1 Datasheet
379Kb / 10P
   Single Synchronous Buck PWM Controller
logo
Fairchild Semiconductor
FAN6520A FAIRCHILD-FAN6520A Datasheet
580Kb / 15P
   Single Synchronous Buck PWM Controller
logo
Richtek Technology Corp...
RT8238B RICHTEK-RT8238B Datasheet
219Kb / 15P
   Single Synchronous Buck PWM Controller
logo
Taiwan Semiconductor Co...
TS3405 TSC-TS3405 Datasheet
409Kb / 10P
   Single Synchronous Buck PWM Controller
logo
Richtek Technology Corp...
RT8228A RICHTEK-RT8228A Datasheet
201Kb / 15P
   Single Synchronous Buck PWM Controller
October 2021
logo
Fairchild Semiconductor
FAN6520B FAIRCHILD-FAN6520B Datasheet
550Kb / 14P
   Single Synchronous Buck PWM Controller
logo
BCD Semiconductor Manuf...
AP3586A,B,C BCDSEMI-AP3586A,B,C Datasheet
624Kb / 17P
   Single Phase Synchronous Buck PWM Controller
AP3581A,B,C BCDSEMI-AP3581A,B,C Datasheet
575Kb / 13P
   Single Phase Synchronous Buck PWM Controller
logo
Richtek Technology Corp...
RT8120 RICHTEK-RT8120_V01 Datasheet
223Kb / 17P
   Single-Phase Synchronous Buck PWM Controller
logo
Diodes Incorporated
AP3581A DIODES-AP3581A Datasheet
756Kb / 13P
   SINGLE PHASE SYNCHRONOUS BUCK PWM CONTROLLER
November 2018 Rev. 2 - 4
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15


Datasheet Descarga

Go To PDF Page


Enlace URL




Política de Privacidad
ALLDATASHEET.ES
¿ALLDATASHEET es útil para Ud.?  [ DONATE ] 

Todo acerca de Alldatasheet   |   Publicidad   |   Contáctenos   |   Política de Privacidad   |   Intercambio de Enlaces   |   Lista de Fabricantes
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