Resonant Converter Controller Timing Synchronization
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Solution Overview
Problem
Resonant switched-mode power converters face challenges in providing suitable timing control for secondary-side synchronous rectifiers relative to primary-side power switches, affecting power conversion efficiency.
Innovation Solution
A controller with an oscillator, advance timing generator, and dead zone generator is used to generate timing signals for secondary-side synchronous rectifiers, ensuring proper synchronization and adjustment of switching frequencies to optimize power conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional timing control methods are used for secondary-side synchronous rectifiers, then device complexity is reduced, but power conversion efficiency deteriorates due to improper timing synchronization between primary-side and secondary-side switches
Solution Approach 1:
The oscillator generates a freeze signal in advance during dead zones to preemptively prevent phase accumulation, ensuring that the secondary-side synchronous rectifier is properly timed relative to the primary-side power switches before the switching event occurs. This preliminary timing control resolves the synchronization issue without requiring complex feedback mechanisms.
Solution Approach 2:
The freeze signal acts as an intermediary mechanism between the dead zone generator and the oscillator phase accumulation process. By introducing this intermediate control signal, the patent achieves precise timing synchronization between primary and secondary switches without directly complexifying the overall controller architecture.
2Measurement precision
If the oscillator continuously accumulates phase during dead zones, then timing precision is maintained, but harmful effects occur due to improper synchronization of secondary-side rectifier timing
Solution Approach 1:
The freeze signal applies preliminary anti-action by preventing phase accumulation during dead zones when improper synchronization would occur. This counter-action is taken in advance to offset the harmful synchronization effects before they can manifest, ensuring proper timing between primary and secondary switches.
Solution Approach 2:
By freezing the oscillator phase during dead zones before secondary-side switching events, the system preemptively establishes correct timing relationships, preventing synchronization errors rather than correcting them after they occur.
Data Source
AI summary
In accordance with an embodiment, a switch controller for a switched-mode power supply includes an oscillator, an advance timing generator, and a dead zone generator. The advance timing generator generates an advance timing output pulse having a first pulse width that is asserted when the oscillator reaches a first phase. The dead zone generator produces a dead zone output having a second pulse width when the advance timing output pulse is de-asserted. This dead zone output pulse is coupled to a freeze input of the oscillator that freezes the phase accumulation of the oscillator when asserted. The controller also has a primary switch logic circuit that produces primary switch drive signals having a dead zone coincident with the dead zone output, and a secondary switch logic circuit that generates a secondary switch drive signal that is de-asserted when the advance timing output pulse becomes asserted.