전자부품 데이터시트 검색엔진
  Korean  ▼
ALLDATASHEET.CO.KR

X  

CS51221EDR16 데이터시트(PDF) 8 Page - ON Semiconductor

부품명 CS51221EDR16
상세설명  Enhanced Voltage Mode PWM Controller
Download  14 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
제조업체  ONSEMI [ON Semiconductor]
홈페이지  http://www.onsemi.com
Logo ONSEMI - ON Semiconductor

CS51221EDR16 데이터시트(HTML) 8 Page - ON Semiconductor

Back Button CS51221EDR16 Datasheet HTML 4Page - ON Semiconductor CS51221EDR16 Datasheet HTML 5Page - ON Semiconductor CS51221EDR16 Datasheet HTML 6Page - ON Semiconductor CS51221EDR16 Datasheet HTML 7Page - ON Semiconductor CS51221EDR16 Datasheet HTML 8Page - ON Semiconductor CS51221EDR16 Datasheet HTML 9Page - ON Semiconductor CS51221EDR16 Datasheet HTML 10Page - ON Semiconductor CS51221EDR16 Datasheet HTML 11Page - ON Semiconductor CS51221EDR16 Datasheet HTML 12Page - ON Semiconductor Next Button
Zoom Inzoom in Zoom Outzoom out
 8 / 14 page
background image
CS51221
http://onsemi.com
8
APPLICATION INFORMATION
THEORY OF OPERATION
Feed Forward Voltage Mode Control
In conventional voltage mode control, the ramp signal has
fixed rising and falling slope. The feedback signal is derived
solely from the output voltage. Consequently, voltage mode
control has inferior line regulation and audio susceptibility.
Feed forward voltage mode control derives the ramp
signal from the input line, as shown in Figure 3. Therefore,
the ramp of the slope varies with the input voltage. At the
start of each switch cycle, the capacitor connected to the FF
pin is charged through a resistor connected to the input
voltage. Meanwhile, the Gate output is turned on to drive an
external power switching device. When the FF pin voltage
reaches the error amplifier output VCOMP, the PWM
comparator turns off the Gate, which in turn opens the
external switch. Simultaneously, the FF capacitor is quickly
discharged to 0.3 V.
Overall, the dynamics of the duty cycle are controlled by
both input and output voltages. As illustrated in Figure 4,
with a fixed input voltage the output voltage is regulated
solely by the error amplifier. For example, an elevated
output voltage reduces VCOMP which in turn causes duty
cycle to decrease. However, if the input voltage varies, the
slope of the ramp signal will react immediately which
provides a much improved line transient response. As an
example shown in Figure 5, when the input voltage goes up,
the rising edge of the ramp signal increases which reduces
duty cycle to counteract the change.
+
VIN
+
VOUT
Power Stage
R
Latch & Driver
GATE
PWM
Feedback
Network
FF
C
COMP
Error Amplifier
FB
Figure 3. Feed Forward Voltage Mode Control
The feed forward feature can also be employed to provide
a volt−second clamp, which limits the maximum product of
input voltage and turn on time. This clamp is used in circuits,
such as Forward and Flyback converter, to prevent the
transformer from saturating. Calculations used in the design
of the volt−second clamp are presented in the Design
Guidelines section.
Figure 4. Pulse Width Modulated by Output
Current with Constant Input Voltage
VOUT
VCOMP
FF
VIN
RTCT
GATE
Figure 5. Pulse Width Modulated by Input Voltage
with Constant Output Current
VIN
VCOMP
FF
IOUT
RTCT
GATE
Powering the IC & UVL
The Undervoltage Lockout (UVL) comparator has two
voltage references; the start and stop thresholds. During
power−up, the UVL comparator disables VREF (which
in−turn disables the entire IC) until the controller reaches its
VCC start threshold. During power−down, the UVL
comparator allows the controller to operate until the VCC
stop threshold is reached. The CS51221 requires only 50
mA
during startup. The output stage is held at a low impedance
state in lock out mode.
During power up and fault conditions, the Soft−Start
clamps the Comp pin voltage and limits the duty cycle. The
power up transition tends to generate temporary duty cycles
much greater than the steady state value due to the low
output voltage. Consequently, excessive current stresses
often take place in the system. Soft−Start technique
alleviates this problem by gradually releasing the clamp on
the duty cycle to eliminate the in−rush current. The duration


유사한 부품 번호 - CS51221EDR16

제조업체부품명데이터시트상세설명
logo
Cherry Semiconductor Co...
CS51221EDR16 CHERRY-CS51221EDR16 Datasheet
164Kb / 12P
   Enhanced Voltage Mode PWM Controller
logo
ON Semiconductor
CS51221EDR16 ONSEMI-CS51221EDR16 Datasheet
178Kb / 14P
   Enhanced Voltage Mode PWM Controller
September, 2005 ??Rev. 8
CS51221EDR16 ONSEMI-CS51221EDR16 Datasheet
178Kb / 14P
   Enhanced Voltage Mode PWM Controller
September, 2005 ??Rev. 8
CS51221EDR16G ONSEMI-CS51221EDR16G Datasheet
178Kb / 14P
   Enhanced Voltage Mode PWM Controller
September, 2005 ??Rev. 8
CS51221EDR16G ONSEMI-CS51221EDR16G Datasheet
178Kb / 14P
   Enhanced Voltage Mode PWM Controller
September, 2005 ??Rev. 8
More results

유사한 설명 - CS51221EDR16

제조업체부품명데이터시트상세설명
logo
ON Semiconductor
CS51221 ONSEMI-CS51221 Datasheet
178Kb / 14P
   Enhanced Voltage Mode PWM Controller
September, 2005 ??Rev. 8
CS51221 ONSEMI-CS51221_09 Datasheet
178Kb / 14P
   Enhanced Voltage Mode PWM Controller
September, 2005 ??Rev. 8
NCP1294 ONSEMI-NCP1294 Datasheet
229Kb / 13P
   Enhanced Voltage Mode PWM Controller
July, 2009 ??Rev. 0
logo
Cherry Semiconductor Co...
CS51221 CHERRY-CS51221 Datasheet
164Kb / 12P
   Enhanced Voltage Mode PWM Controller
logo
ON Semiconductor
CS51021A ONSEMI-CS51021A Datasheet
130Kb / 11P
   Enhanced Current Mode PWM Controller
February, 2006 ??Rev. 8
logo
Cherry Semiconductor Co...
CS51021 CHERRY-CS51021 Datasheet
170Kb / 9P
   Enhanced Current Mode PWM Controller
logo
Semtech Corporation
SC1103 SEMTECH-SC1103 Datasheet
97Kb / 8P
   VOLTAGE MODE PWM CONTROLLER
logo
Shaoxing Devechip Micro...
SDC7500 SDC-SDC7500 Datasheet
308Kb / 10P
   Voltage Mode PWM Controller
logo
Taiwan Semiconductor Co...
TS494 TSC-TS494 Datasheet
138Kb / 7P
   Voltage Mode PWM Controller
logo
List of Unclassifed Man...
AP494 ETC-AP494 Datasheet
175Kb / 8P
   VOLTAGE MODE PWM CONTROLLER
More results


Html Pages

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


데이터시트 다운로드

Go To PDF Page


링크 URL




개인정보취급방침
ALLDATASHEET.CO.KR
ALLDATASHEET 가 귀하에 도움이 되셨나요?  [ DONATE ] 

Alldatasheet는?   |   광고문의   |   운영자에게 연락하기   |   개인정보취급방침   |   링크교환   |   제조사별 검색
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