Switching Power Supply Mode Transition for Stable Output Voltage
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Solution Overview
Problem
Existing switching power supplies experience oscillations in output voltage during transitions between pulse suppression and continuous conduction modes when operating with average output loads, and there is a need for more efficient and energy-saving solutions.
Innovation Solution
Implementing a comparator that compares the output voltage with a reference voltage for at least 20% of the conduction phase of a switch, and transitioning between modes based on this comparison, along with a zero current detection circuit to manage the switching power supply's operating modes, reducing delays and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the switching power supply operates in pulse suppression mode to reduce energy consumption, then energy efficiency is improved, but output voltage oscillations occur during mode transitions
Solution Approach 1:
The patent applies preliminary action by forcing the comparator output to a specific state for at least 20% of the conduction time before actual mode transition occurs. This preliminary forcing of the comparator output prepares the control circuit in advance, ensuring a smoother transition from pulse suppression mode to continuous conduction mode and preventing output voltage oscillations while maintaining energy efficiency benefits
2Stability of the object's composition
If the comparator continuously monitors output voltage to prevent oscillations, then output voltage stability is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic action by having the comparator operate in a forced state during specific portions of the conduction cycle (at least 20% of the conduction time) rather than continuously monitoring. This periodic forcing of the comparator output reduces energy consumption compared to continuous monitoring while still maintaining output voltage stability during critical transition periods
3Stability of the object's composition
If the mode transition is delayed until current is zero to reduce oscillations, then output voltage stability is improved, but response time worsens
Solution Approach 1:
The patent applies preliminary action by forcing the comparator output in advance during the conduction phase, which prepares the control circuit before the actual mode transition is needed. This preliminary action reduces the effective response time for mode transitions while maintaining output voltage stability, as the control circuit is already prepared when the transition becomes necessary
Data Source
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AI summary
The present description relates to a switching power supply comprising: - a first switch connecting a first node receiving a first supply voltage to a second node providing a second output voltage; - a second switch connecting a third node receiving a fourth reference voltage to said second output node; and - a comparator adapted to compare said second output voltage to a third comparison voltage, wherein, when the switching power supply operates in a pulse suppression mode, the comparator is adapted to indicate that the second output voltage is higher than the third comparison voltage during a part of the conduction phase of said first switch, and wherein the switching power supply transitions from a pulse suppression mode to a continuous conduction mode as soon as said second output voltage is lower than said third comparison voltage.