Bidirectional Flyback Converter Communication via Pulse Transformer
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Solution Overview
Problem
Existing secondary-side controlled flyback converters lack bidirectional communication between the primary-side and secondary-side controllers, leading to inefficiencies and potential damage due to miscommunication and lack of feedback.
Innovation Solution
Implementing a bidirectional communication scheme between the primary-side controller (PSC) and the secondary-side controller (SSC) using a pulse transformer for signal transmission, allowing the SSC to control the active clamp FET on the primary side and enabling acknowledgement signals to confirm receipt of control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If unidirectional control signals are used from secondary-side to primary-side, then device complexity is reduced, but reliability deteriorates due to lack of feedback and potential miscommunication
Solution Approach 1:
The patent implements bidirectional communication by adding an acknowledgment signal path from primary-side controller back to secondary-side controller. This feedback mechanism confirms successful receipt of control signals, enabling the secondary-side controller to detect communication failures and implement retry logic, thereby significantly improving communication reliability without requiring complete system redesign
Solution Approach 2:
The patent introduces a communication protocol with intermediate acknowledgment signals as mediators between the primary-side and secondary-side controllers. These acknowledgment signals serve as intermediaries that carry status information back to the controlling side, enabling reliable communication without direct complex interaction between controllers
2Reliability
If bidirectional communication is implemented, then communication reliability is improved, but device complexity increases due to additional signal paths
Solution Approach 1:
The patent utilizes the existing pulse transformer in the flyback converter circuit to carry both power-related signals and communication signals. By making the pulse transformer multi-functional, the patent avoids adding separate communication hardware, thus improving reliability through bidirectional communication while minimizing the increase in device complexity
3Object-affected harmful factors
If simultaneous MOSFET activation is prevented through communication, then converter damage risk is reduced, but communication overhead increases
Solution Approach 1:
The patent implements preliminary action by having the primary-side controller send an acknowledgment signal immediately upon receiving a control signal, before any potential harmful event can occur. This early confirmation allows the secondary-side controller to proactively prevent simultaneous MOSFET activation by adjusting its timing, thus reducing damage risk with minimal time overhead
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 enhances the reliability and efficiency of the flyback converter by ensuring accurate communication and preventing simultaneous activation of primary and secondary MOSFETs, thus reducing the risk of converter damage.
Implementation Method 1
a pulse transformer coupled between the primary side and the secondary side. The pulse transformer transmits a control signal from the secondary-side controller to the primary-side controller
Data Source
AI summary
An USB-PD power converter with primary and secondary side controllers that bidirectionally communicate with each other. In one embodiment, the USB-PD power converter has a first transformer in data communication with the primary-side controller and the secondary-side controller. The secondary-side controller is configured to generate control signals and receive acknowledgement signals from the primary-side controller via the first transformer. The primary-side controller is configured to generate the acknowledgment signals and receive the control signals from the secondary-side controller via the first transformer.