Datasheet.kr   

RT7738 데이터시트 PDF




Richtek에서 제조한 전자 부품 RT7738은 전자 산업 및 응용 분야에서
광범위하게 사용되는 반도체 소자입니다.


 

PDF 형식의 RT7738 자료 제공

부품번호 RT7738 기능
기능 Multi-Mode Flyback Controller
제조업체 Richtek
로고 Richtek 로고


RT7738 데이터시트 를 다운로드하여 반도체의 전기적 특성과 매개변수에 대해 알아보세요.




전체 24 페이지수

미리보기를 사용할 수 없습니다

RT7738 데이터시트, 핀배열, 회로
RT7738
SmartJitterTM Multi-Mode Flyback Controller
General Description
The RT7738 series are enhanced high efficient
multi-mode PWM flyback controller with proprietary
SmartJitterTM technology. The innovative SmartJitterTM
technology can not only reduces the EMI emissions of
SMPS when the system enters green mode, but also
eliminates the output jittering ripple. Also, the RT7738
series feature Continuous Conduction Mode (CCM)
and valley switching multi-mode control to optimize the
product performance. To meet the stringent trend
toward performance in recent years, the RT7738 series
are the best choice for product designers.
The RT7738 is available in SOT-23-6 package, and it is a
current mode PWM controller. Comprehensive protection
and programmable functions are built-in, including a
programmable propagation delay time compensation, a
programmable output Over-Voltage Protection (OVP), a
programmable external Over-Temperature Protection
(OTP), and a programmable bulk capacitor Brown-in/
Brown-out protection. With the above features, the
RT7738 is a cost-effective and compact solution for
AC/DC products.
Features
Proprietary SmartJitterTM Technology
Reducing EMI Emissions of SMPS
Output Jittering Ripple Elimination
Continuous Conduction Mode (CCM) and Valley
Switching Mode Control
Ultra-low Start-up current (<3A)
Accurate Over-Load Protection (OLP)
Programmable Propagation Delay Time
Compensation
Programmable Output Over-Voltage Protection
Programmable External Over-Temperature
Protection
Programmable Bulk Capacitor Brown-in/Brown-out
Protection
Driver Capability : 200mA/300mA
High Noise Immunity
Applications
Switching AC/DC Adaptor
NB Adaptor
TV/Monitor Standby Power
PC Peripherals
Simplified Application Circuit
Mains
(90V to 265V)
CCOMP
VDD
DMAG
GATE
COMP RT7738
GND
CS
(Optional)
(Optional)
(Optional)
(Optional)
VO+
VO-
Copyright © 2014 Richtek Technology Corporation. All rights reserved.
DS7738-00 November 2014
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1




RT7738 pdf, 반도체, 판매, 대치품
RT7738
Operation
Multi-mode PWM
The RT7738 is a multi-mode PWM controller, and a
constant oscillator is built-in to allow the system
operating in CCM. As the load decreases, the system
enters DCM, and the oscillator converts to valley
switching mode control. In lighter load or no load
conditions, the controller enters green mode. The
RT7738 provides multi-mode control to optimize the
product performance under different load conditions.
Oscillator
The oscillator runs at 65kHz and features frequency
jittering function. The saw-tooth slope compensation,
maximum duty cycle pulse and over-load protection
slope are built-in. Its jitter depth is proportion of
oscillator frequency where f is frequency jittering
range, and TJIT is frequency jittering period.
Leading Edge Blanking (LEB)
To prevent unexpectedly gate switching interruption
from the initial spike on CS pin, the LEB delay is
designed to block this spike at the beginning of gate
switching.
Gate Driver
A totem pole gate driver is designed to meet both EMI
and efficiency requirements in low power applications.
An internal pull-low circuit is activated after pretty low
VDD to prevent external MOSFET from accidentally
turning on during UVLO.
DMAG Pin
The DMAG pin detects the input voltages of bulk
capacitor and output voltage by auxiliary winding and
resistor divider. According to the DMAG signal, the
RT7738 provides protections, including output
over-voltage protection, and programmable bulk
capacitor Brown-in/Brown-out protection.
Over-Load Protection
In over-load conditions, current limit for a long time will
lead to system thermal stress problem. To further
protect the system, the RT7738 is designed with a
proprietary prolonged turn-off period during hiccup. The
power loss and temperature during OLP are averaged
to an acceptable level over the ON/OFF cycle.
CS Pin Open Protection
When the CS pin is opened, the controller will shut
down after a few cycles.
Internal VDD Over-Voltage Protection
Output voltage can be roughly sensed by the VDD pin.
If the sensed voltage reaches VOVP threshold, the
controller shuts down after deglitch delay.
Feedback Open and Opto-Coupler Short
If the output voltage feedback loop is open or the
opto-coupler is shorted, the OVP/OLP function will be
triggered depending on which one occurs first.
Output Short Protection
The RT7738 implements output short protection by
detecting output signal of DMAG pin. It can minimize
the power loss and temperature during output short,
especially at high line input voltage.
Secondary Rectifier Short Protection
The current spike during secondary rectifier short test
is extremely high because of the saturated main
transformer. Meanwhile, the transformer acts like a
leakage inductance. During high line, the current in
power MOSFET is sometimes too high in OLP delay
time. To offer better and easier protection design, the
RT7738 shuts down after a few of cycles before fuse is
impacted.
Copyright © 2014 Richtek Technology Corporation. All rights reserved.
www.richtek.com
4
is a registered trademark of Richtek Technology Corporation.
DS7738-00 November 2014

4페이지










RT7738 전자부품, 판매, 대치품
RT7738
Parameter
Symbol
Test Conditions
Min Typ Max Unit
GATE Section
Rising Time
TR CL = 1nF
-- 250 --
ns
Falling Time
TF CL = 1nF
-- 30 -- ns
Gate Output Clamping Voltage VCLAMP VDD = 23V
-- 13 --
V
DMAG Section
Threshold Voltage of
Over-voltage Protection
VDMAG_OVP
2.45 2.5 2.55 V
Blanking Time Before
Over-voltage Protection of
DMAG Pin
TBK_OVP VCS = 0.36V
RT7738G/L/A
RT7738H
2.1 2.9
1.25 1.95
3.7
2.5
s
Threshold Voltage of
Under-voltage Protection
VDMAG_UVP After TD_OSP, COMP pin open
0.3 0.4 0.5 V
Delay Time of Under-voltage
Protection
TD_OSP
fOSC = 65kHz, RT7738G/L/A
fOSC = 100kHz, RT7738H
-- 16 --
-- 10.4 --
ms
On Threshold Current
IDMAG_BNI
141 160 179 A
Threshold Current of
Under-current Protection
IDMAG_BNO
128 145 162 A
Maximum Sourcing Current of
DMAG Pin
IDMAG_MAX
(Note 5)
-- -- 1 mA
Delay Time of Under-current
Protection
TD_BNO
fOSC = 65kHz, RT7738G/L
fOSC = 65kHz, RT7738A
fOSC = 100kHz, RT7738H
-- 64 --
-- 32 --
-- 41.6 --
ms
Over-Temperature Protection (OTP) Section
OTP Before Turn On
TOTP_INTH Built-in OTP (Note 5)
-- 130 -- C
OTP After Turn On
TOTP_STTH Built-in OTP (Note 5)
-- 140 -- C
Note1. Stresses beyond those listed ”Absolute Maximum Ratings” may cause permanent damage to the device. These are
stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the
operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect
device reliability.
Note 2. θJA is measured in natural convection (still air) at TA = 25°C with the component mounted on a low effective thermal
conductivity test board of JEDEC 51-3 thermal measurement standard.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
Note 5. Guaranteed by design.
Copyright © 2014 Richtek Technology Corporation. All rights reserved.
DS7738-00 November 2014
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
7

7페이지


구       성 총 24 페이지수
다운로드[ RT7738.PDF 데이터시트 ]

당사 플랫폼은 키워드, 제품 이름 또는 부품 번호를 사용하여 검색할 수 있는

포괄적인 데이터시트를 제공합니다.


구매 문의
일반 IC 문의 : 샘플 및 소량 구매
-----------------------------------------------------------------------

IGBT, TR 모듈, SCR 및 다이오드 모듈을 포함한
광범위한 전력 반도체를 판매합니다.

전력 반도체 전문업체

상호 : 아이지 인터내셔날

사이트 방문 :     [ 홈페이지 ]     [ 블로그 1 ]     [ 블로그 2 ]



관련 데이터시트

부품번호상세설명 및 기능제조사
RT7730

Burst Triple-mode PWM Flyback Controller

Richtek
Richtek
RT7736

PWM Flyback Controller

Richtek
Richtek

DataSheet.kr       |      2020   |     연락처      |     링크모음      |      검색     |      사이트맵