Two-Phase DC-DC Converter with Auxiliary Inductor for ZVS
Solution Overview
Problem
Switched-mode power supplies face challenges in reducing both ohmic and switching losses, as increasing transistor size to minimize resistance leads to higher parasitic capacitance and increased switching losses, necessitating a compromise between these losses.
Innovation Solution
A two-phase DC-DC converter design with interleaved buck converter stages and an auxiliary inductor for zero-voltage switching (ZVS) conditions, eliminating the need for additional logic and reducing voltage ripples, thereby allowing smaller capacitance values and minimizing losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If additional switches and auxiliary inductor are added to achieve zero-voltage switching, then switching losses are reduced, but device complexity increases
Solution Approach 1:
The auxiliary inductor is designed to serve multiple functions: enabling zero-voltage switching for both the first and second converter stages, and providing current sharing between stages. The same auxiliary inductor is shared by both phases, eliminating the need for separate auxiliary inductors for each stage and reducing overall component count.
Solution Approach 2:
The circuit uses the existing inductor currents from the buck converter stages to automatically charge and discharge the parasitic capacitances of the switches during switching transitions. This self-assisted ZVS mechanism eliminates the need for additional active control circuits or extra switching components to achieve soft switching.
2Stability of the object's composition
If larger capacitance values are used to reduce output voltage ripples, then voltage stability improves, but component size and cost increase
Solution Approach 1:
The patent uses multiple parallel converter stages that deliver current to a common output node. The interleaved operation of these stages results in current ripple cancellation, where the ripple currents from different stages subtract from each other. This segmentation approach reduces output voltage ripple without requiring large capacitance values, as the effective ripple frequency is multiplied and amplitudes are reduced.
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 reduces output voltage ripples and achieves self-assisted ZVS, minimizing losses and optimizing the size of passive components, while maintaining efficient power conversion.
Implementation Method 1
A switched-mode power supply comprises a first auxiliary inductor configured to generate a first inductive current
Implementation Method 2
outputting an output voltage comprising LC filtering signals obtained from a first node between the first set of switches and from a second node between the second set of switches
Data Source
AI summary
The switched-mode power supply includes a first switch connected to an input terminal for receiving an input voltage, a second switch, a first node between the first switch and the second switch. The switched-mode power supply further includes a third switch connected to the input terminal, a fourth switch, and a second node between the third switch and the fourth switch. A first inductor is connected between the first node and an output terminal, a second inductor is connected between the second node and the output terminal, at least one third inductor is connected between the first node and the second node, and a capacitor is connected to the output terminal.