Inverting Buck-Boost Converter Circuit for Reverse Recovery Mitigation
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Solution Overview
Problem
Conventional inverting buck boost converters operating in continuous conduction mode experience significant reverse recovery issues, leading to voltage and current spikes that reduce power efficiency.
Innovation Solution
The implementation of an auxiliary circuit within the inverting buck boost converter, which includes additional switches, inductors, and capacitors, allows for the transfer of energy stored in the body diode and output capacitance to an auxiliary inductor, thereby minimizing reverse bias and reducing current spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional switching method is implemented in an inverting buck boost converter operating in continuous conduction mode, then the converter can maintain continuous voltage at the output, but voltage and current spikes occur due to reverse recovery of transistors, reducing power efficiency
Solution Approach 1:
The auxiliary circuit proactively transfers energy from the body diode and output capacitance to the auxiliary inductor before the main switching transition occurs. This preliminary energy transfer ensures that when the transistor switches states, there is minimal stored energy in the body diode, preventing reverse recovery current spikes and improving power efficiency while maintaining continuous conduction mode operation
2Loss of energy
If additional switches, inductors, and capacitors are added to reduce reverse recovery effects, then power efficiency is improved, but device complexity increases
Solution Approach 1:
The auxiliary circuit components (auxiliary inductor, body diode, and output capacitance) are integrated into the existing inverting buck boost converter topology. The auxiliary inductor is coupled to the existing switching nodes, and the body diode is naturally formed by the transistor structure, merging the reverse recovery mitigation function with the existing power conversion architecture rather than adding completely separate components
Solution Approach 2:
The auxiliary inductor serves as an intermediary energy storage element that mediates the energy transfer from the body diode and output capacitance. Instead of directly switching the main transistor with stored energy that causes reverse recovery, the auxiliary inductor provides a controlled path for energy transfer, isolating the main switching operation from the reverse recovery effects
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 solution effectively reduces current spikes and enhances power efficiency by ensuring that the body diode of the second switch is completely discharged before reverse biasing, thus preventing energy wastage and maintaining stable output voltage.
Implementation Method 1
transfer of energy stored in the body diode and output capacitance to an auxiliary inductor
Implementation Method 2
energy stored in the body diode
Implementation Method 3
energy stored in the body diode and output capacitance
Data Source
AI summary
An example apparatus includes: a first and second capacitor; a first and second inductor; a first switch having a first and second terminal, the first terminal coupled to the first capacitor, and the second terminal coupled to the first and second inductor; a second switch having a third and fourth terminal, the third terminal coupled to the second terminal, the fourth terminal coupled to the second capacitor; a third switch having a fifth and sixth terminal, the fifth terminal coupled to the first terminal, the sixth terminal coupled to the second inductor; and a diode having a seventh and eighth terminal, the seventh terminal coupled to the sixth terminal, the eighth terminal coupled to the fourth terminal.