Adaptive Threshold Switching Power Supply Control
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Solution Overview
Problem
Conventional flyback switching converters experience high system loss and low efficiency due to the conventional driving method, which results in significant energy wastage and inefficient energy transfer.
Innovation Solution
A driving method and circuit for a switching mode power supply that involves turning off the auxiliary switch after the auxiliary current reaches a reference current and turning on the primary switch after the primary switching voltage reaches its valley value, with the reference auxiliary current adjusted based on threshold valley voltages to optimize energy transfer and reduce losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the auxiliary switch is turned off after the auxiliary current reaches a preset reference auxiliary current in conventional driving method, then the control is simple, but the system loss is large and efficiency is low
Solution Approach 1:
The patent implements feedback control by detecting the valley value of the primary switching voltage and using it to dynamically adjust the reference auxiliary current. The control circuit monitors the primary switching voltage waveform, identifies the valley point, and feeds this information back to modify the reference current threshold, creating a closed-loop control system that optimizes switching timing based on actual operating conditions.
Solution Approach 2:
The reference auxiliary current is transformed from a fixed preset value to a dynamic variable that changes based on the detected valley value of the primary switching voltage. This dynamic adjustment allows the system to adapt the auxiliary switch turn-off timing to varying load conditions and voltage levels, optimizing performance across different operating points rather than relying on a static threshold.
2Use of energy by moving object
If the reference auxiliary current is kept constant in conventional driving method, then the control circuit is simple, but the energy transfer efficiency is low
Solution Approach 1:
The patent changes the parameter of reference auxiliary current from a constant value to a variable that depends on the valley value of the primary switching voltage. By establishing a relationship between these two parameters, the system optimizes energy transfer efficiency through parameter adaptation rather than using a fixed current threshold, allowing the reference current to scale with operating conditions.
3Loss of energy
If the auxiliary switch is turned off based on fixed reference current threshold, then the switching control is straightforward, but significant energy wastage occurs
Solution Approach 1:
The system performs preliminary detection of the valley value of the primary switching voltage before determining the optimal reference auxiliary current threshold. By预先 (in advance) identifying the valley point characteristics, the control circuit can set an optimized reference current that prevents excessive energy wastage during the auxiliary switch off-state, rather than relying on post-hoc adjustments.
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
This approach decreases system losses and improves efficiency by adjusting the reference auxiliary current to manage the valley value of the primary switching voltage, thereby enhancing the overall performance of the switching mode power supply.
Implementation Method 1
a transformer having a primary winding and an auxiliary winding with an auxiliary current flowing through the auxiliary winding
Data Source
AI summary
A switching mode power supply with an adaptive setting of a threshold valley voltage. The switching mode power supply decreases a reference auxiliary current when a valley value of a primary switching voltage across a primary switch is smaller than a first threshold valley voltage. And in addition, the switching mode power supply can increase the reference auxiliary current when the valley value of the primary switching voltage is larger than a second threshold valley voltage.