DC-DC Converter Circuit With Capacitive Divider for High-Voltage Isolation
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Solution Overview
Problem
Designing high-voltage DC-DC converter circuits for reduced pressure environments, such as in-flight aircraft, poses challenges due to corona and partial discharge sensitivity, and the need for custom, non-standard pulse transformers that increase PCB size and costs.
Innovation Solution
A high-voltage DC-DC converter circuit design that includes a high-side transistor, a low-side transistor, a gate driver power supply, a converter control, and a capacitance divider network, with isolation transformers to reduce voltage stress and eliminate the need for custom pulse transformers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If custom non-standard pulse transformers are used in high-voltage DC-DC converters, then voltage stress is managed and reliability is maintained, but PCB size increases and unit cost increases
Solution Approach 1:
The pulse transformer is divided into two separate components: a standard high-voltage transformer and a capacitance divider network. This segmentation allows the use of off-the-shelf transformers with standard footprints while maintaining the required voltage stress management through the capacitance divider, thereby reducing PCB size without compromising reliability
Solution Approach 2:
The invention changes the electrical parameters at the transformer output by introducing a capacitance divider network. This network transforms the voltage and impedance characteristics to match the requirements of the secondary side, allowing standard transformers to be used instead of custom-designed ones, thus reducing PCB area while maintaining proper voltage stress distribution
2Reliability
If custom non-standard pulse transformers are used in high-voltage DC-DC converters, then voltage stress is managed and reliability is maintained, but unit cost increases
Solution Approach 1:
The high-voltage transformer is designed with universal standard specifications that can be purchased off-the-shelf, eliminating the need for custom manufacturing. The capacitance divider network provides the specialized voltage transformation function, allowing the transformer itself to be a standard component, thus reducing unit cost while maintaining reliability through proper voltage stress management
Solution Approach 2:
The invention replaces expensive custom-designed pulse transformers with a combination of inexpensive standard transformers and simple capacitance divider components. This substitution significantly reduces unit cost while achieving the same functional outcome through a more economical component selection
3Stress or pressure
If custom non-standard pulse transformers are used in high-voltage DC-DC converters, then voltage stress is managed, but supply chain requirements increase
Solution Approach 1:
The transformer is specified with standard universal parameters that are widely available in the supply chain, eliminating the need for custom manufacturing and complex supply chain arrangements. The capacitance divider network handles the specialized voltage management requirements, allowing the transformer to be a standard off-the-shelf component with reliable supply chain support
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 circuit design reduces voltage stress by half, eliminates the need for custom transformers, and maintains reliability while minimizing PCB size and costs, thus addressing the challenges of high-voltage converter circuits in reduced pressure environments.
Implementation Method 1
The capacitance divider network includes a first capacitor and a second capacitor. The first capacitor is electrically connected in series, at a DC-link midpoint node, to the second capacitor. The first capacitor is also electrically connected to the positive DC supply terminal, and the second capacitor is electrically connected to the negative DC supply terminal.
Implementation Method 2
The gate driver power supply is electrically isolated from the high-side transistor and the low-side transistor
Data Source
AI summary
A DC-DC converter circuit includes a high-side transistor, a low side transistor, a gate driver power supply, a converter control, and a capacitance divider network. The high-side transistor includes a high-side drain terminal, a high-side source terminal, and a high-side gate terminal. The high-side drain terminal is coupled to a positive DC supply terminal. The gate driver power supply is electrically isolated from the high-side transistor and the low-side transistor. The converter control is configured to supply high-side control commands and low-side control commands to the high-side transistor and the low-side transistor, respectively. The capacitance divider network includes a first capacitor and a second capacitor. The first capacitor is electrically connected in series, at a DC-link midpoint node, to the second capacitor. The DC-link midpoint node, the gate driver power supply, and the converter control are all electrically connected to, and share, a local electrical ground.