®
RT7740GAD/GHD
SmartJitter
TM
Multi-Mode Flyback Controller
General Description
The RT7740GAD/GHD is an enhanced high-efficiency
multi-mode PWM flyback controller, incorporating
Richtek's proprietary SmartJitter
TM
technology. The
innovative SmartJitter
TM
technology is used to reduce EMI
emissions of a switch-mode power supply in green mode,
and at the same time eliminate the output ripple due to
frequency jittering. In operation, the RT7740GAD/GHD
features a multi-mode control scheme, operating from the
continuous-conduction mode (CCM) to the discontinuous-
conduction mode (DCM) with valley switching, to achieve
high efficiency and the optimal performance with high
efficiency.
The RT7740GAD/GHD operates as a current-mode PWM
controller for flyback converters. It contains
comprehensive and programmable protection features,
consisting of propagation delay compensation, output
over-voltage protection (OVP), external over-temperature
protection (OTP), and bulk-capacitor brown-in/brown-out
protection. With above features, the RT7740GAD/GHD
enables one to achieve a cost-effective and compact design
for a wide-range AC-DC conversion applications. It is
available in an SOT-23-6 package.
Features
Proprietary SmartJitter
TM
Technology
�½
Reducing EMI Emissions of SMPS
�½
Eliminating
Frequency-Jittering-Induced Output
Ripple
Operating in Continuous-Conduction Mode (CCM),
Discontinuous-Conduction Mode (DCM), DCM with
Valley-Switching
Ultra-low Start-Up Current (< 3μA)
μ
Accurate Over-Current Protection (OCP)
Programmable Line 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 Adapter
NB Adapter
TV/Monitor Standby Power
PC Peripherals
Simplified Application Circuit
V
O+
Mains
(90V to 265V)
V
O-
(Option)
DMAG
VDD
GATE
COMP
RT7740GAD/GHD
CS
GND
C
COMP
Copyright
©
2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS7740GAD_GHD-01
November 2019
www.richtek.com
1
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
