Zero Voltage Switching Power Supply Control Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional switching mode power supplies face challenges in achieving higher power density and efficiency due to volume limitations in electronic devices, necessitating increased switching frequency and improved adapter efficiency to support fast-charging technologies.
Innovation Solution
The implementation of a switching mode power supply with a primary and secondary switch circuit, controlled by a primary and secondary control circuit, which turns on the primary switch circuit based on current or voltage thresholds and controls the secondary switch circuit to be ON for a period before the primary switch circuit is activated, enabling zero voltage switching and reducing power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If switching frequency is increased to reduce passive component size, then power density is improved, but power loss increases due to non-zero voltage switching
Solution Approach 1:
The secondary switch circuit is turned on in advance before the primary switch circuit to pre-discharge the parasitic capacitor of the primary switch, ensuring zero voltage across the primary switch before it turns on. This preliminary action eliminates voltage overlap during switching, reducing power loss while enabling high switching frequency operation with reduced passive component size.
2Productivity
If switching frequency is increased to support fast-charging, then power density is improved, but adapter efficiency deteriorates due to increased switching losses
Solution Approach 1:
The secondary switch circuit is activated in advance to pre-discharge the primary switch's parasitic capacitor, ensuring the primary switch turns on at zero voltage. This eliminates switching losses that would otherwise increase with frequency, enabling fast-charging capability while maintaining adapter efficiency.
3Reliability
If conventional feedback control is used with opto-coupler, then electrical isolation is maintained, but device volume increases due to component size
Solution Approach 1:
The patent extracts and eliminates the opto-coupler from the feedback circuit by implementing a feedback control method that operates without requiring electrical isolation components. The control circuit directly senses primary side parameters and controls switching based on these measurements, removing the volume-consuming opto-coupler while maintaining system reliability.
Data Source
AI summary
A switching mode power supply with zero voltage switching is discussed. It adopts a primary control circuit to turn on a primary switch circuit when a current flowing through the primary switch circuit reaches an inverse current threshold or when a variation rate of a voltage signal indicative of a voltage across the primary switch circuit reaches a rate threshold.