Switching Power Supply Controller Standby Mode Detection
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Solution Overview
Problem
Switching power supply apparatuses face issues with erroneous transitions from standby to normal mode due to varying response times of feedback signals, leading to transient resonance currents and audible noise, especially when feedback response is quick.
Innovation Solution
A controller for a current resonance switching power supply apparatus that includes a load current detection circuit and a standby detection circuit, which generates feedback signals and load current signals to accurately determine the mode of operation, preventing erroneous transitions by using a delay circuit and NOR circuit to ensure stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the feedback response time is short to enable quick detection of standby mode, then the responsiveness of the power supply is improved, but erroneous transitions from standby to normal mode occur due to transient feedback voltage changes
Solution Approach 1:
The patent applies preliminary action by requiring the feedback voltage to exceed the threshold for a predetermined time period before confirming mode transition. This preliminary verification step prevents erroneous transitions caused by transient feedback voltage changes while maintaining quick response capability through the fast feedback response.
2Use of energy by moving object
If burst control is implemented to reduce standby power consumption, then energy efficiency is improved, but audible noise is generated due to transient resonance currents during switching
Solution Approach 1:
The patent applies preliminary anti-action by detecting standby mode beforehand and preemptively suppressing the resonance current before burst control switching occurs. This prevents the transient resonance current that causes audible noise while maintaining the energy-saving benefits of burst control.
Solution Approach 2:
The patent converts the harmful resonance current into a beneficial detection mechanism. By detecting the resonance current, the system identifies when to suppress it, thereby eliminating audible noise while maintaining efficient standby operation through burst control.
3Object-generated harmful factors
If soft start and soft end operations are performed to eliminate audible noise, then noise reduction is achieved, but device complexity increases
Solution Approach 1:
The patent extracts the essential function of noise suppression by selectively suppressing only the resonance current during standby mode transitions, rather than implementing full soft start and soft end operations. This reduces device complexity while maintaining effective noise reduction.
Data Source
AI summary
A controller of a current resonance switching power supply apparatus configured to supply a constant output voltage to a load. The current resonance switching power supply apparatus includes a resonance circuit, and generates a feedback signal indicative of an error between the output voltage and a target voltage. The controller includes a load current detection circuit that receives a part of a resonance current of the resonance circuit, performs averaging and outputs a load current signal, and a standby detection circuit that receives the feedback signal and the load current signal, and determines that the load is in a standby mode upon detecting that the load current signal is lower than a first threshold and the feedback signal is lower than a second threshold, and is in a normal mode upon detecting that the feedback signal continues to be higher than the second threshold for more than a predetermined time.