Power Supply Load Detection Using Burst Mode Pause Windows
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Solution Overview
Problem
Existing methods for detecting whether a load is connected to or detached from a power supply device face challenges in accurately determining the connection status due to increased output voltage ripple and reduced room for adding a test signal, especially in burst mode operations, which limits the effectiveness of load detection.
Innovation Solution
A method and device that determine the necessity of load detection based on a detection voltage, estimate a specific time point during a switching or burst cycle when the output voltage decreases, and apply a test signal for a predetermined period without switching operations, allowing for accurate comparison of waveforms to detect load connection or detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the switching frequency is decreased, then the load detection accuracy is improved, but the response speed deteriorates
Solution Approach 1:
The patent applies periodic action by using burst mode operation where the power supply device switches between active and idle states in periodic cycles. During each burst cycle, multiple switching operations are performed to maintain output voltage, followed by a pause period. This periodic operation allows the system to achieve effective load detection during the pause periods while maintaining adequate response through the repeated burst cycles, thus resolving the contradiction between detection accuracy and response speed.
2Measurement precision
If the test signal amplitude is increased, then the load detection accuracy is improved, but the output voltage stability deteriorates
Solution Approach 1:
The patent applies preliminary action by performing load detection during the pause periods between burst cycles, before the next switching operation begins. This timing allows the test signal to be applied without interfering with the voltage regulation process, as the power switch is already in an off state. The detection is completed in advance of the next voltage adjustment cycle, thus improving detection accuracy while maintaining output voltage stability.
3Stability of the object's composition
If the output voltage ripple is reduced, then the room for test signal addition is increased, but the load detection capability deteriorates
Solution Approach 1:
The patent applies dynamics by adapting the load detection strategy to the dynamic burst mode operation characteristics. Instead of using continuous detection that would require excessive voltage margin, the system dynamically selects pause periods within the burst cycle as optimal detection windows. This dynamic approach allows load detection capability to be maintained by utilizing the natural voltage stabilization periods, while keeping the test signal amplitude within safe margins that preserve output voltage stability.
Data Source
AI summary
A load detecting method relates to detecting connection or detachment between a power supply device and a load, and the load detecting method includes steps of determining whether a load detection operation is necessary or not, based on a detection voltage corresponding to an output voltage from the power supply device, when determining the load detection operation to be necessary, estimating a specific time point in a first period during which the output voltage of the power supply device decreases from a first level to a second level, and applying a test signal to the output voltage for a predetermined detection period with reference to the specific time point. The switching operation of a power switch of the power supply device does not occur in the first period.