Synchronous Rectifier Green Mode Control via Dynamic Reference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power converter controllers waste energy when operating in discontinuous conduction mode or quasi-resonant mode due to a fixed reference value for determining the green mode, which does not account for changes in forbidden turning-on time caused by output voltage variations.
Innovation Solution
A synchronous rectifier with a forbidden turning-on time generation circuit and a green mode signal generation circuit that dynamically adjusts the reference value based on the output voltage, enabling or disabling the green mode signal accordingly, allowing the controller to enter or leave the green mode based on the forbidden turning-on time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed reference value is used to determine green mode entry, then the control logic is simple, but the controller cannot enter green mode when forbidden turning-on time changes with output voltage, resulting in energy waste
Solution Approach 1:
The reference value is changed from a fixed parameter to a dynamic parameter that varies with output voltage. The green mode reference value generation circuit dynamically adjusts the reference value based on the output voltage level, allowing the controller to correctly determine green mode entry conditions when the forbidden turning-on time changes with output voltage, thereby reducing energy waste while maintaining reasonable control logic complexity
Solution Approach 2:
The invention changes the parameter of reference value from constant to variable. By making the reference value change with output voltage, the system adapts to different operating conditions and correctly identifies green mode entry points even when forbidden turning-on time varies, solving the energy waste problem without significantly increasing system complexity
2Loss of energy
If the reference value is changed with output voltage, then the controller can correctly enter green mode when forbidden turning-on time changes, but the control system becomes more complex
Solution Approach 1:
The system implements dynamic adjustment of the reference value based on output voltage through a dedicated green mode reference value generation circuit. This circuit dynamically generates appropriate reference values corresponding to different output voltage levels, enabling accurate green mode detection while keeping the overall control system architecture relatively simple and modular
Solution Approach 2:
The green mode reference value generation circuit acts as an intermediary component that bridges the output voltage signal and the green mode determination logic. It processes the output voltage information and generates the corresponding dynamic reference value, isolating the complexity from the main control logic and making the system easier to implement and maintain
Data Source
AI summary
A synchronous rectifier applied to a secondary side of a power converter includes a forbidden turning-on time generation circuit, a green mode signal generation circuit, and a controller. The forbidden turning-on time generation circuit generates a forbidden turning-on time corresponding to the secondary side according to a synchronous signal of the secondary side. The green mode signal generation circuit enables a green mode signal when the forbidden turning-on time is greater than a reference value by at least one time, and disables the green mode signal when the forbidden turning-on time is continuously less than a reference value by a predetermined number of times. The reference value is changed with an output voltage of the secondary side. The controller enters a green mode when the green mode signal is enabled, and leaves the green mode when the green mode signal is disabled.