Switching Power Source Topology Without Diode Bridge Losses
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Solution Overview
Problem
Existing switching power sources face increased losses and costs due to the need for larger heat sinks as output power increases, primarily because of the inefficiencies in diode bridges and power factor correction circuits, which lead to higher input currents and increased board area requirements.
Innovation Solution
A power source device configuration that eliminates diode bridges by using a switching power source with FETs, capacitors, and an inductive load, where the control portion manages the switching elements based on detected AC voltage polarity to apply a square wave voltage directly, effectively performing active clamp operations without diode bridges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If diode bridges and power factor correction circuits are used in switching power sources, then rectification and smoothing of AC voltage can be achieved, but losses increase and heat sink requirements increase as output power increases
Solution Approach 1:
The patent removes the diode bridge and power factor correction circuit from the conventional switching power source configuration. By extracting these loss-generating components, the invention achieves synchronous rectification using only switching elements (FETs), thereby eliminating rectification losses and the associated heat dissipation requirements.
Solution Approach 2:
The invention changes the operating parameters of the switching elements by controlling their on/off states based on AC voltage polarity detection. This parameter control enables the switching elements to function as synchronous rectifiers, replacing the passive diode bridge and eliminating the need for large heat sinks.
2Ease of manufacture
If diode bridges are used for rectification, then AC voltage can be converted to DC voltage, but the number of elements increases and board area increases
Solution Approach 1:
The switching elements (FETs) in the invention serve multiple functions: they perform both the rectification function traditionally handled by diode bridges and the power switching function. This multi-functionality eliminates the need for separate diode bridge components, reducing the overall board area while maintaining full rectification capability.
Solution Approach 2:
The patent merges the rectification function with the power switching function by using the same switching elements for both purposes. By combining these functions into a single component set, the invention reduces the total number of elements required and minimizes board area occupation.
3Power
If output power of switching power source is increased, then power delivery capability is improved, but input current increases and losses in diode bridge increase
Solution Approach 1:
The invention converts the harmful effect of high input current (which causes losses in diode bridges) into a beneficial operation by using synchronous rectification. The switching elements are controlled to minimize conduction losses even at high currents, and the detect portion uses the voltage polarity information to optimize the switching timing, thereby reducing losses while maintaining high power delivery capability.
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 configuration reduces power consumption and losses by allowing synchronous rectification of the AC power source, suppressing input voltage rectification losses, and minimizing the number of elements needed, resulting in an efficient switching power source without the need for diode bridges.
Implementation Method 1
a first capacitor connected between the first terminal and the second terminal of the first switching element; a second capacitor serially connected between the second terminal of the second switching element and the second terminal of the fourth switching element; a third capacitor connected between the first terminal and the second terminal of the third switching element
Implementation Method 2
an inductive load connected between the second terminal of the first switching element and the second terminal of the third switching element
Data Source
AI summary
A power source device includes first FET of which a source is connected to LIVE phase, second FET of which a source is connected to a drain of the first FET, third FET of which a source is connected to NEUTRAL phase, fourth FET of which a source is connected to a drain of the third FET, first capacitor connected between the source and the drain of the first FET, second capacitor serially connected between the drain of the second FET and the drain of the fourth FET, third capacitor connected between the source and the drain of the third FET, fourth capacitor connected between the LIVE and NEUTRAL phases, a detector to detect potentials of the LIVE and NEUTRAL phases, a controller controls the FETs based on a detecting result by the detector, and an inductive load connected between the drains of the first and third FETs.