The RT7789B series is an enhanced high-efficiency multi-mode PWM flyback controller, incorporating Richtek's proprietary PowerZeroTM and SmartJitterTM technology. The innovative PowerZeroTM technology, featuring an integrated HV device, provides an excellent green power solution, while the SmartJitterTM technology can reduce EMI emissions of a switch-mode power supply in green mode as well as eliminate the output ripple due to frequency jittering. In addition, the RT7789B series 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 optimal performance.

The RT7789B is a current-mode PWM controller for flyback converters, integrated with comprehensive and programmable protection features, which include brown-in/brown-out protection, VDD over-voltage protection (VDD OVP), output over-voltage and under-voltage protection (Output OVP and UVP), secondary rectifier short-circuit protection (SRSP), and external over-temperature protection (External OTP). For the constant output power regulation, a resistor connected to CS pin can be used to achieve an accurate line compensation across the universal input voltage range. With these features, the RT7789B enables one to accomplish a cost-effective and compact design for a wide range of AC-DC conversion applications.

应用

Switching AC-DC Adapter

NB Adapter

Printer Adapter

关键特性

Proprietary PowerZeroTM Technology

Integrating a 700V Start-up Device

Brown-In/Brown-Out Protection

Proprietary SmartJitterTM Technology

Reducing EMI Emissions of SMPS

Eliminating Frequency-Jittering-Induced Output Ripple

Operating in Continuous-Conduction Mode (CCM), Discontinuous-Conduction Mode (DCM), and DCM with Valley Switching

Accurate Over-Current Protection (OCP)

Programmable Line Compensation

Programmable Output OVP and UVP

Programmable External OTP

Driver Capability : 300mA/-300mA

High Noise Immunity

RoHS Compliant and Halogen Free