Resonance Voltage Attenuation Detection Circuit for Switching Power Supplies
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Solution Overview
Problem
Conventional switching power supplies face challenges in maintaining efficient operation and minimizing noise and ripple when switching between PWM and quasi-resonance control modes, especially when the output voltage is switched, leading to fluctuations in resonance amplitude detection and potential sound noise.
Innovation Solution
A resonance voltage attenuation detection circuit is implemented, utilizing a first voltage comparator and a time-out circuit to detect attenuation in the resonance voltage of a transformer's winding, allowing for precise control of switching element timing to ensure stable operation in both PWM and quasi-resonance modes, thereby reducing switching loss, noise, and ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the switching power supply switches between PWM control and quasi-resonance control during normal operation, then power efficiency is improved and switching loss is reduced, but switching noise and ripple increase
Solution Approach 1:
The patent changes the control mode parameters dynamically by switching between PWM and quasi-resonance control based on operating conditions. The power control IC monitors system state and adjusts the control method to optimize power efficiency while managing switching noise through parameter adjustment rather than fixed operation mode.
Solution Approach 2:
The patent implements dynamic control by allowing the switching power supply to transition between PWM and quasi-resonance control modes during normal operation. This dynamic adaptation enables the system to respond to changing load conditions and optimize performance, with the power control IC managing mode transitions based on real-time operational parameters.
2Adaptability or versatility
If the output voltage is switched to different levels, then adaptability is improved, but resonance amplitude detection becomes unstable leading to sound noise
Solution Approach 1:
The patent employs feedback mechanisms where the power control IC continuously monitors the resonance voltage amplitude and uses this information to adjust control parameters. When output voltage switching causes resonance amplitude to drop below reliable detection thresholds, the feedback system detects this condition and triggers appropriate corrective actions to maintain stable operation and prevent sound noise.
Solution Approach 2:
The patent implements preliminary detection of resonance voltage amplitude before switching operations. The power control IC monitors resonance characteristics in advance and prepares appropriate control adjustments to prevent detection instability during voltage transitions, ensuring smooth switching between output voltage levels without causing sound noise.
3Measurement precision
If the resonance voltage amplitude becomes small during voltage switching, then measurement precision deteriorates, but control stability is required
Solution Approach 1:
The patent introduces an intermediary detection mechanism that monitors resonance voltage amplitude through a dedicated detection circuit in the power control IC. This intermediary system provides early warning when amplitude becomes too small for reliable detection, allowing the main control system to take preventive actions before measurement precision deteriorates enough to affect switching cycle stability.
Solution Approach 2:
The patent implements preliminary anti-action by detecting when resonance voltage amplitude is approaching levels that would compromise measurement precision. The power control IC takes preventive measures before actual detection failure occurs, such as adjusting control parameters or preventing switching operations that would cause amplitude to drop below reliable thresholds, thereby maintaining switching cycle stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively stabilizes the switching cycle and reduces noise and ripple, enhancing average power efficiency and miniaturizing transformer components, ensuring a compact and efficient switching power supply.
Implementation Method 1
a first voltage comparator circuit that compares a voltage of the winding with a predetermined first voltage
Implementation Method 2
a time-out circuit that performs clocking operation in accordance with an output of the first voltage comparator circuit
Implementation Method 3
a voltage conversion transformer; a transformer having an auxiliary winding and monitor a voltage (including a divided voltage) induced in the auxiliary winding
Data Source
AI summary
A resonance voltage attenuation detection circuit detects attenuation of a resonance voltage of a winding of a transformer. The resonance voltage attenuation detection circuit includes a first voltage comparator circuit and a time-out circuit. The first voltage comparator circuit compares a voltage of the winding with a predetermined first voltage. The time-out circuit performs clocking operation in accordance with an output of the first voltage comparator circuit. The time-out circuit outputs an attenuation detection signal when the time-out circuit has clocked a preset period which is shorter than a time required for a peak voltage of the winding to be attenuated from the first voltage to a predetermined second voltage lower than the first voltage.