データシートサーチシステム
  Japanese  ▼
ALLDATASHEET.JP

X  

FAN6751MRMY データシート(PDF) 3 Page - Fairchild Semiconductor

部品番号 FAN6751MRMY
部品情報  Highly Integrated Green-Mode PWM Controller
Download  13 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
メーカー  FAIRCHILD [Fairchild Semiconductor]
ホームページ  http://www.fairchildsemi.com
Logo FAIRCHILD - Fairchild Semiconductor

FAN6751MRMY データシート(HTML) 3 Page - Fairchild Semiconductor

  FAN6751MRMY Datasheet HTML 1Page - Fairchild Semiconductor FAN6751MRMY Datasheet HTML 2Page - Fairchild Semiconductor FAN6751MRMY Datasheet HTML 3Page - Fairchild Semiconductor FAN6751MRMY Datasheet HTML 4Page - Fairchild Semiconductor FAN6751MRMY Datasheet HTML 5Page - Fairchild Semiconductor FAN6751MRMY Datasheet HTML 6Page - Fairchild Semiconductor FAN6751MRMY Datasheet HTML 7Page - Fairchild Semiconductor FAN6751MRMY Datasheet HTML 8Page - Fairchild Semiconductor FAN6751MRMY Datasheet HTML 9Page - Fairchild Semiconductor Next Button
Zoom Inzoom in Zoom Outzoom out
 3 / 13 page
background image
AN-6073
APPLICATION NOTE
© 2008 Fairchild Semiconductor Corporation
www.fairchildsemi.com
Rev. 1.0.0 • 9/26/08
3
Internal Block Operation
Startup and Soft-Start Circuitry
When power is turned on, the internal high-voltage startup
current (typically 2mA) charges the hold-up capacitor C1
through startup resistor RHV. RHV can be directly connected
by VBULK to the HV pin. The built-in 5ms soft-start circuit
starts when the VDD pin reaches the start threshold voltage
VDD-ON. Soft-start helps reduce the inrush current, the startup
current spike, and output voltage overshoot during the
startup period, as shown in Figure 4. When VDD reaches
VDD-ON, the internal high-voltage startup current is switched
off and the supply current is drawn from the auxiliary
winding of the main transformer, as shown in Figure 5.
S Q
R
Soft
Driver
Soft Start
8
6
VDD
GATE
Sense
Figure 4.
Soft-start Circuit
Figure 5. Startup Circuit for Power Transfer
If a shorter startup time is required, a two-step startup
circuit, as shown Figure 6, is recommended. In this circuit, a
smaller capacitor C1 can be used to reduce startup time. The
energy supporting the FAN6751 after startup is mainly from
a larger capacitor C2. If a shorter releasing latch mode time
is required, a DHV and RHV can be directly connected by VAC
to the HV pin.
When the supply current is drawn from the transformer, it
draws a leakage current of about 1µA from HV pin. The
maximum power dissipation of the RHV is:
W
K
A
I
R
L
I
P
HV
Typ
C
HV
RHV
μ
μ
1
.
0
100
2
2
.)
(
Ω
×
=
×
=
(1)
where
IHV-LC is the supply current drawn from HV pin, and
RHV is 100KΩ.
Figure 6. UVLO Specification
Under-Voltage Lockout (UVLO)
The FAN6751 has a voltage detector on the VDD pin to
ensure that the chip has enough power to drive the
MOSFET. Figure 7 shows a hysteresis of the turn-on and
turn-off threshold levels and an open-loop-release voltage.
Figure 7. UVLO Specification
The turn-on and turn-off thresholds are internally fixed at
16.5V and 10.5V. During startup, the VDD’s capacitor must
be charged to 16.5V to enable the IC. The capacitor
continues to supply the VDD until the energy can be
delivered from the auxiliary winding of the main
transformer. The VDD must not drop below 10.5V during the
startup sequence.
To further limit the input power under a short-circuit or
open-loop condition, a special two-step UVLO mechanism
prolongs the discharge time of the VDD capacitor. Figure 8
shows the traditional UVLO method along with the special
two-step UVLO method. In the two-step UVLO mechanism,
an internal sinking current, IDD-OLP, pulls the VDD voltage
toward the VDD-OLP. This sinking current is disabled after the
VDD drops below VDD-OLP; after which, the VDD voltage is
again charged towards VDD-ON. With the addition of the two-
step UVLO mechanism, the average input power during a
short-circuit or open-loop condition is greatly reduced. As a
result, over-heating does not occur.


同様の部品番号 - FAN6751MRMY

メーカー部品番号データシート部品情報
logo
Fairchild Semiconductor
FAN6751MRMY FAIRCHILD-FAN6751MRMY Datasheet
468Kb / 13P
   Highly-Integrated Green-Mode PWM Controller
More results

同様の説明 - FAN6751MRMY

メーカー部品番号データシート部品情報
logo
List of Unclassifed Man...
SG6846 ETC1-SG6846 Datasheet
3Mb / 14P
   Highly-Integrated Green-Mode PWM Controller
logo
Fairchild Semiconductor
SG6846A FAIRCHILD-SG6846A Datasheet
490Kb / 13P
   Highly Integrated Green-Mode PWM Controller
SG6741 FAIRCHILD-SG6741 Datasheet
619Kb / 13P
   Highly-Integrated Green-Mode PWM Controller
FAN6862WLTY FAIRCHILD-FAN6862WLTY Datasheet
2Mb / 16P
   Highly Integrated Green-Mode PWM Controller
SG6846B FAIRCHILD-SG6846B Datasheet
451Kb / 15P
   Highly Integrated Green-Mode PWM Controller
SG6741A FAIRCHILD-SG6741A Datasheet
557Kb / 12P
   Highly Integrated Green-Mode PWM Controller
SG6846A FAIRCHILD-SG6846A_08 Datasheet
476Kb / 15P
   Highly Integrated Green-Mode PWM Controller
SG6846G FAIRCHILD-SG6846G Datasheet
376Kb / 14P
   Highly Integrated Green-Mode PWM Controller
FAN6751MR FAIRCHILD-FAN6751MR Datasheet
468Kb / 13P
   Highly-Integrated Green-Mode PWM Controller
FAN6863RTY FAIRCHILD-FAN6863RTY Datasheet
1Mb / 16P
   Highly Integrated Green-Mode PWM Controller
SG5842A FAIRCHILD-SG5842A_09 Datasheet
573Kb / 15P
   Highly Integrated Green-Mode PWM Controller
More results


Html Pages

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


データシート ダウンロード

Go To PDF Page


リンク URL




プライバシーポリシー
ALLDATASHEET.JP
ALLDATASHEETはお客様のビジネスに役立ちますか?  [ DONATE ] 

Alldatasheetは   |   広告   |   お問い合わせ   |   プライバシーポリシー   |   リンク交換   |   メーカーリスト
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