High Bandwidth Power Supply Using GaN Switching Converters
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Solution Overview
Problem
Traditional power instruments with linear devices face high power dissipation issues at low output voltage and high current, requiring aggressive thermal management, which increases solution density, cost, and acoustic noise, while switching converters struggle with efficiency and responsiveness, especially at zero volts.
Innovation Solution
The use of high-speed switching converters with Gallium-nitride transistors and a multi-phase switching converter topology with both positive and negative DC rails, along with pulse width modulation and resonant filters, to achieve high efficiency and responsiveness, reducing thermal management needs and enabling wider control bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If linear devices are used to achieve high response speed and high output impedance, then responsiveness is improved, but power dissipation increases significantly
Solution Approach 1:
The patent changes the operating parameters of the transistor by using it in switching mode rather than linear mode. The transistor operates in cutoff or saturation regions instead of the active region, fundamentally changing its electrical characteristics to reduce power dissipation while maintaining responsiveness through high-frequency switching operation.
Solution Approach 2:
The patent employs periodic switching action where the transistor is rapidly turned on and off at high frequency. This periodic operation allows the device to spend minimal time in high-dissipation states while maintaining the ability to respond quickly to control signals, effectively reducing average power dissipation compared to continuous linear operation.
2Reliability
If aggressive thermal management is implemented to handle large power dissipation, then reliability is improved, but solution density decreases and cost increases
Solution Approach 1:
The patent extracts the thermal management burden from the system by eliminating the source of excessive heat generation. By switching the transistor to operation in cutoff or saturation regions, the design removes the continuous high-power dissipation problem that would require complex thermal management, fans, and heatsinks.
3Loss of energy
If switching converters are used to reduce power dissipation, then energy efficiency is improved, but responsiveness deteriorates especially at zero volts
Solution Approach 1:
The patent changes the switching frequency parameter to operate at very high frequencies, which enables the switching converter to respond quickly to control signals and load changes. This high-frequency operation, combined with appropriate LC filter design, maintains responsiveness while keeping the switching device out of the linear region where power dissipation occurs.
4Speed
If high switching frequency is used to improve responsiveness, then control bandwidth is improved, but switching losses increase
Solution Approach 1:
The patent changes the transistor technology parameter by using Gallium-nitride (GaN) transistors instead of traditional silicon devices. GaN transistors have superior switching characteristics with lower on-resistance and faster switching speeds, which reduces both conduction losses during the on-state and switching losses during transitions, enabling high-frequency operation with minimal power loss.
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 power dissipation, thermal management requirements, and noise, while maintaining high output impedance and responsiveness, especially at zero volts, by efficiently managing switching frequencies and currents.
Implementation Method 1
The gates of switch 11 and switch 12 are controlled by a pulse width modulator 14
Implementation Method 2
resonant filters, to achieve high efficiency and responsiveness
Data Source
AI summary
A switching converter has a first converter output for connection to a user load and a second converter output for connection to the user load. A first direct current rail power negative terminal has a first positive output and a first negative output connected to the second converter output. A second direct current rail power negative terminal has a second negative output and a second positive output connected to the first positive output. A first switch has a first positive terminal connected to the first positive output, a first negative terminal and a first control terminal. A second switch has a second positive terminal connected to the first negative terminal, a second negative terminal connected to the second negative output, and a second control terminal. A pulse width modulator has a first modulator output connected to the first control terminal, and a second modulator output connected to the second control terminal. An inductance is connected between the first converter output and the first negative terminal. A comparator controls the first pulse width modulator based on a voltage difference between a current measurement voltage that varies based on current through the inductance and a first set point voltage.