Switching Power Supply Pulse Width Holder for Light Load Efficiency
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Solution Overview
Problem
Conventional switching power supply devices experience efficiency deterioration due to short pulse widths of switching control signals during light load conditions, leading to switching losses and inadequate power supply to the load.
Innovation Solution
A switching power supply device with a feedback voltage clamp circuit that holds the pulse width of the switching control signal at a minimum capable of contributing to power supply, incorporating a pulse width modulation oscillator and a feedback voltage clamp circuit to regulate the pulse width, ensuring efficient power delivery to the load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pulse width of the switching control signal is reduced during light load conditions, then the switching frequency increases and power conversion speed improves, but the pulse width becomes too short to supply sufficient power to the load and switching losses increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the pulse width of the switching control signal based on load conditions. During light load conditions, the pulse width is maintained at a minimum threshold value rather than being reduced proportionally with the load, preventing the pulse width from becoming too short. This parameter adjustment resolves the contradiction by ensuring the pulse width remains sufficient for power supply while adapting to light load conditions, thereby reducing switching losses without compromising power delivery capability.
2Use of energy by moving object
If the pulse width of the switching control signal is reduced during light load conditions, then the switching frequency increases and efficiency improves, but the power supply capability to the load becomes insufficient
Solution Approach 1:
The patent implements parameter changes by establishing a minimum pulse width threshold that prevents the pulse width from becoming too short during light load conditions. The control circuit monitors the pulse width and maintains it above the threshold value, ensuring sufficient power supply capability to the load while still adapting to light load conditions to improve efficiency. This resolves the contradiction by finding an optimal parameter range that balances efficiency improvement with adequate power delivery.
3Adaptability or versatility
If the switching control signal pulse width is allowed to vary freely with load conditions, then the system adapts to different load demands, but during light load conditions the pulse width becomes too short causing switching losses and efficiency deterioration
Solution Approach 1:
The patent applies parameter changes by introducing a minimum pulse width threshold that constrains the pulse width variation during light load conditions. The control circuit includes a pulse width modulation unit that ensures the pulse width remains above this threshold value, preventing excessive shortening that would cause switching losses. This resolves the contradiction by maintaining load adaptation capability through controlled parameter adjustment while preventing the harmful effect of overly short pulse widths.
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 improves power supply efficiency by maintaining a sufficient pulse width for the switching control signal, reducing switching losses and enhancing the overall efficiency of the power supply, especially during light load conditions.
Implementation Method 1
a flyback transformer 102... a primary winding L1 of a flyback transformer 102... a secondary winding L2 of the flyback transformer 102
Implementation Method 2
a diode bridge 101 rectifies full waves from a commercially-available alternating current power supply 100
Data Source
AI summary
A switching power supply device includes a switching element connected in series with a primary winding of a transformer, to which an input voltage is applied, a switching operation unit configured to obtain an output voltage from a secondary winding of the transformer, and a controller configured to control switching of the switching element. The controller includes an oscillator configured to output a switching control signal of controlling the switching element, a feedback voltage determination circuit, a drive circuit including a comparator and the like, and a pulse width holder configured to hold a pulse width of the switching control signal, when the load is light, at least at a minimum pulse width capable of contributing to supplying the power to a load.