Supply circuit for power module with built-in isolation transformer and associated power module
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Solution Overview
Problem
Conventional isolated power supplies for power modules are limited by a narrow operating temperature range, bulkiness, and mechanical stress vulnerabilities, which hinder their integration into compact power modules and effective heat management.
Innovation Solution
A compact electrical power supply circuit using a transformer with a primary and secondary circuit on double-sided substrates, featuring adjustable metal tracks and connectors for reduced stray capacitance, improved high-temperature resistance, and optional polymer encapsulation or magnetic core, allowing for enhanced mechanical and thermal reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional isolated power supplies are used, then isolation function is provided, but the operating temperature range is limited and the size is bulky
Solution Approach 1:
The power supply circuit is segmented into two separate substrates (first substrate and second substrate) that can be independently manufactured and optimized. This segmentation allows each substrate to be designed for specific temperature ranges and cooling requirements, enabling extended operating temperature ranges while maintaining compact overall size through precise spatial arrangement.
Solution Approach 2:
The invention transitions from a single-plane transformer design to a three-dimensional dual-substrate configuration. By stacking substrates vertically and using electrical connectors to establish connections through the thickness direction, the design achieves compact footprint while providing adequate thermal management pathways in multiple dimensions.
2Temperature
If transformer is integrated into PCB, then isolation function is achieved, but the operating temperature range remains limited
Solution Approach 1:
The transformer is divided into primary winding on first substrate and secondary winding on second substrate, with electrical connectors providing the magnetic coupling path. This segmentation allows each substrate to be optimized for high-temperature operation independently, avoiding the temperature limitations of conventional integrated PCB transformers while managing integration complexity through standardized connector interfaces.
Solution Approach 2:
Electrical connectors serve as intermediaries between the two substrates, providing both electrical connection and magnetic coupling pathways. These connectors are specifically designed to maintain electrical integrity and magnetic flux continuity at high temperatures, enabling extended operating temperature ranges without requiring complex direct integration of the transformer into the PCB.
3Temperature
If single-sided substrate is used for inductance, then integration is simplified, but heat sink capacity is limited
Solution Approach 1:
The design transitions from single-sided substrate to double-sided substrate configuration, utilizing both the front and back surfaces of each substrate for heat dissipation. This dimensional utilization effectively doubles the available heat sink capacity compared to single-sided designs, while the substrate structure remains relatively simple through standard manufacturing techniques.
Solution Approach 2:
The first and second substrates are merged into a stacked configuration where both substrates contribute to heat sinking. The electrical connectors and magnetic circuit elements serve dual purposes of electrical connection and thermal management, combining multiple functions into integrated components that improve heat sink capacity without proportionally increasing device complexity.
4Reliability
If transformer with wound wire is used, then isolation function is provided, but mechanical resistance to vibrations and thermal cycles is reduced
Solution Approach 1:
The invention replaces the mechanical wound wire transformer construction with a planar transformer design using printed metal tracks on substrates. This substitution eliminates the mechanical vulnerabilities of wound wire to vibrations and thermal cycling, while achieving the same electrical transformation and isolation functions through electromagnetic induction in a rigid, vibration-resistant planar structure.
Solution Approach 2:
The transformer employs composite construction combining substrate materials, metal track materials, and connector materials with complementary properties. This composite approach optimizes mechanical resistance to vibrations and thermal cycles by selecting materials with matched thermal expansion coefficients and high structural integrity, while maintaining the necessary electrical and magnetic performance.
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 enables a compact, reliable, and high-temperature-resistant power supply circuit with controlled stray capacitance, improving mechanical resistance and extending the operating temperature range beyond 150°C, suitable for integration within power modules.
Implementation Method 1
an electrical transformer including a primary circuit and a secondary circuit
Data Source
AI summary
Electrical power supply circuit for a power module comprising an electrical transformer, a first substrate having a first side including a heat sink and a second side, a second substrate having a first side including a heat sink and a second side, first metal tracks disposed on the second side of the first substrate, second metal tracks disposed on the second side of the second substrate, electrical connectors disposed between the first and second substrates to electrically connect a first metal track to a second metal track, the primary circuit of the electrical transformer comprising a first part of the first metal tracks and a first part of the second metal tracks, and the secondary circuit of the electrical transformer comprising a second part of the first metal tracks and a second part of the second metal tracks.