PowerZero^TM Multi-Mode Flyback Controller

The RT7789B series is an enhanced high-efficiency multi-mode PWM flyback controller, incorporating Richtek's proprietary PowerZero^TM and SmartJitter^TM technology. The innovative PowerZero^TM technology, featuring an integrated HV device, provides an excellent green power solution, while the SmartJitter^TM 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.