Switched Capacitor Converter Using Inductive Charge Transfer
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Solution Overview
Problem
Current switched capacitor voltage converters suffer from low conversion efficiency and high switching loss due to significant conduction and switching losses in switch transistors.
Innovation Solution
The addition of an inductive branch between two branches of a conventional Dickson switched capacitor voltage converter allows for the transfer of electric charges on parasitic capacitors from one branch to another via an inductor during the dead time when primary switch transistors are turned off, effectively reducing the voltage difference across switch transistors to zero.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional Dickson switched capacitor voltage converter structure is used, then the circuit has simple power conversion structure, but the conversion efficiency is low due to significant switching loss and conduction loss
Solution Approach 1:
The inductive branch pre-charges or pre-discharges the parasitic capacitors of the switch transistors before the main switching action occurs. During the dead time when primary switches are turned off, the inductor transfers charges to/from the parasitic capacitors, ensuring that when the switches are turned on again, the voltage difference across them is minimized or zero, thereby reducing switching loss.
Solution Approach 2:
The inductive branch acts as an intermediary between the two branches of the switched capacitor voltage converter. It mediates the charge transfer between parasitic capacitors of different branches, enabling zero voltage switching by controlling the charge distribution through the inductor during the dead time intervals.
2Power
If more switch transistors are used to achieve voltage conversion, then the voltage conversion ratio can be achieved, but the conduction loss and switching loss increase
Solution Approach 1:
The parasitic capacitors of the switch transistors, which normally represent unwanted energy storage elements, are utilized by the inductive branch to perform useful charge transfer functions. The inductor exploits the charge already present on these parasitic capacitors to reduce switching losses, turning a harmful factor into a beneficial resource for improving overall converter efficiency.
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 significantly reduces switching loss and improves conversion efficiency by ensuring zero voltage switching of primary switch transistors.
Implementation Method 1
an electric charge or electric charges on parasitic capacitors of one branch are completely transferred to another branch via the inductor
Data Source
AI summary
A switched capacitor voltage converter includes an inductive branch and two branches, by controlling a turning on and off of switch transistors, charges on a parasitic capacitor of one branch are completely transferred to another branch of the two branches via the inductive branch within a period of time after primary switch transistors are turned off, and voltage difference between both terminals of each of the primary switch transistors become zero, and then the primary switch transistors are started to be turned on, the respective voltage differences of the primary switch transistors are zero at a moment when the primary switch transistors are turned on.