HEMT Power Circuit Sigmoid Gate Driver for DC-DC Converter Loss Reduction
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Solution Overview
Problem
Conventional diodes experience significant energy losses due to circulation and switching losses, which are substantial in applications like rectifier diodes, bridge rectifiers, and DC to DC converters, necessitating a reduction in these losses to align with energy-saving trends.
Innovation Solution
A power circuit utilizing a High Electron Mobility Transistor (HEMT) and a gate driver circuit, where the gate driver circuit forms a sigmoid function between the gate and source of the HEMT, reducing energy loss by operating according to specific characteristic equations, and the HEMT generates a rectification characteristic similar to a diode with energy loss proportional to the gate region area, significantly less than conventional diodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional diode is used as a rectifier element, then the rectifying function is achieved, but the circulation loss and switching loss are significant
Solution Approach 1:
The patent changes the fundamental parameters of the rectifier element by replacing the diode's p-n junction structure with a HEMT's field effect structure. This parameter change enables the rectifier to achieve lower on-resistance and faster switching characteristics, directly reducing circulation loss and switching loss while maintaining the rectifying function.
Solution Approach 2:
The patent substitutes the conventional diode's physical rectifying mechanism (p-n junction) with a field-effect controlled mechanism (HEMT). This substitution allows for electronic control of the rectifying action through gate voltage, enabling reduced loss operation while maintaining circuit functionality.
2Loss of energy
If the cut-off voltage of the diode is reduced to lower circulation loss, then the energy consumption decreases, but the diode's rectifying performance deteriorates
Solution Approach 1:
The patent changes the controlling parameter from fixed diode cut-off voltage to dynamically controllable HEMT gate voltage. This allows optimization of the on-resistance parameter independently from the rectifying function, achieving low circulation loss without compromising rectifying performance through precise gate voltage control.
3Loss of energy
If a HEMT is used instead of a diode, then the energy loss is reduced significantly, but the device structure becomes more complex
Solution Approach 1:
The HEMT structure serves multiple functions simultaneously: it provides the rectifying action, the switching function, and the low-resistance conduction path. This multi-functionality consolidates what would otherwise require separate components, reducing overall device complexity despite the advanced transistor structure.
Solution Approach 2:
The patent merges the rectifier and switch functions into a single HEMT device, eliminating the need for separate diode and switch components. This consolidation reduces the total number of components and interconnections, offsetting the increased complexity of the HEMT structure itself.
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 proposed solution reduces energy loss by approximately ¼ to ⅕ compared to conventional diodes, achieving lower circulation and switching losses while maintaining high efficiency and fast switching capabilities.
Implementation Method 1
a High Electron Mobility Transistor (HEMT) and a gate driver circuit... the HEMT generates a rectification characteristic similar to a diode with energy loss proportional to the gate region area
Data Source
AI summary
A power circuit is applicable to a Direct Current (DC) to DC converter. The power circuit includes a gate driver circuit and a High Electron Mobility Transistor (HEMT). The gate driver circuit functions as a Sigmoid (S) function and controls a gate and a source of the HEMT with a cross voltage of the sigmoid (S) type function. Accordingly, an overall characteristic curve of the HEMT and the gate driver circuit is like a characteristic curve of a single rectifier diode, so as to achieve a rectifying, freewheeling, or reversing effect. In addition, since an energy loss is low when the HEMT is conducted, the energy loss of the whole power circuit is much less than that of a conventional diode.