Galvanically Isolated Power Converter Dual Controller
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Solution Overview
Problem
Switch mode power supplies face challenges in efficiently regulating output voltage and managing energy transfer across galvanically isolated primary and secondary controllers, particularly in varying loading conditions, leading to inefficiencies and potential output voltage drops.
Innovation Solution
The implementation of a power converter with a primary controller and a secondary controller, both galvanically isolated, where the secondary controller transmits request signals to control the power switch's ON state and determines the turn-off conditions based on loading conditions, ensuring efficient energy transfer and output voltage regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single controller is used to regulate output voltage and control power switch, then device complexity is reduced, but output voltage regulation precision and energy transfer efficiency deteriorate under varying loading conditions
Solution Approach 1:
The controller is divided into two separate controllers: a primary controller that controls the power switch and an auxiliary controller that monitors output voltage and generates request signals. This segmentation allows each controller to specialize in specific functions, improving output voltage regulation precision while maintaining manageable device complexity through clear functional division.
2Reliability
If the power switch is kept ON for longer periods to meet heavy loading demands, then output voltage regulation is maintained, but energy transfer efficiency and switching component reliability worsen due to increased thermal stress
Solution Approach 1:
The auxiliary controller generates periodic request signals that trigger the primary controller to switch the power switch ON only when needed. This periodic action pattern allows the power switch to remain OFF during light loading conditions, reducing thermal stress and improving energy transfer efficiency, while still maintaining output voltage stability by switching ON during heavy loading demands.
3Speed
If the power switch switching frequency is increased to improve response to loading changes, then output voltage regulation speed is improved, but energy losses and thermal effects on components worsen
Solution Approach 1:
The system dynamically adjusts the power switch switching frequency based on actual loading conditions. The auxiliary controller monitors output voltage and generates request signals at varying frequencies: higher frequency during light loading to improve response speed, and lower frequency during heavy loading to reduce switching losses. This dynamic adaptation resolves the contradiction between response speed and energy efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables precise regulation of output voltage and efficient energy transfer, maintaining desired output levels even under heavy loading conditions by adjusting turn-off conditions and request signal rates, thereby enhancing the overall efficiency and stability of the power converter.
Implementation Method 1
The energy transfer element (e.g., a coupled inductor) may include a primary winding and a secondary winding that are galvanically isolated from one another
Data Source
AI summary
A power converter controller includes a primary controller and a secondary controller. The primary controller is coupled to receive one or more request signals from the secondary controller and transition a power switch from an OFF state to an ON state in response to the received request signals. The secondary controller is coupled to transmit the request signals to the primary controller and control the amount of time between the transmission of each of the request signals. The secondary controller includes a timing circuit that sets a minimum amount of time between the transmission of the request signals. The secondary controller also includes a secondary switch control circuit coupled to trigger the timing circuit in response to transmitting a request signal.