Transformer-Isolated Gate Driver With Adaptive Bias Boost
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Solution Overview
Problem
Existing drive circuits for semiconductor switches face challenges in providing an economical and efficient solution that can accommodate varying current and voltage requirements across different types of switches, leading to increased manufacturing costs and inefficiencies, especially in higher power applications.
Innovation Solution
A drive circuit design that incorporates a transformer with a primary and secondary side circuit, allowing for flexible gate charge handling by using a secondary bias circuit with a storage capacitor and an external bootstrap capability, enabling it to adapt to different gate charge levels through a combination of internal and external components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If drive circuits are designed to provide higher current and voltage for higher power applications, then gate charge handling capability is improved, but manufacturing cost increases
Solution Approach 1:
The drive circuit incorporates a selectable bias configuration that allows dynamic adjustment between different operating modes. A second bias circuit with storage capacitor can be selectively enabled or disabled based on the specific application requirements, allowing the same circuit to adapt to both low-power and high-power applications without requiring different manufacturing processes
Solution Approach 2:
The drive circuit is designed with universal functionality to handle multiple types of semiconductor switches (MOSFETs, IGBTs, GaN FETs, SiC FETs) with varying gate charge requirements. The circuit can operate in two modes: using only the primary bias circuit for lower power applications, or combining primary and secondary bias circuits for higher power applications, making it suitable for a broad range of applications without increasing manufacturing complexity
2Power
If drive circuits are designed with higher current and voltage capabilities, then power delivery is improved, but efficiency decreases
Solution Approach 1:
The circuit dynamically selects between different bias configurations based on actual power requirements. The second bias circuit with storage capacitor is only activated when higher power delivery is needed, allowing the circuit to maintain high efficiency in low-power applications while providing adequate power capability when required
Solution Approach 2:
The circuit changes its operational parameters by selectively enabling or disabling the second bias circuit. This parameter change allows the same hardware to operate at different power levels with optimized efficiency characteristics for each operating point, avoiding the continuous energy loss that would result from always operating at maximum capability
3Device complexity
If external bias supplies are eliminated, then device complexity is reduced, but gate charge handling capability for high power applications is limited
Solution Approach 1:
The patent merges the primary bias circuit and secondary bias circuit into a single integrated drive circuit. The storage capacitor and second bias circuit are incorporated within the same device package, eliminating the need for external bias supplies while maintaining the capability to handle high gate charge requirements through the combined bias circuits
Solution Approach 2:
The second bias circuit with storage capacitor is nested within the overall drive circuit architecture, which itself is integrated with the transformer and primary bias circuit. This nested structure allows multiple functional elements to be contained within a single device, reducing external component requirements while maintaining enhanced gate charge handling capability
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 design enhances gate charge handling capability, reduces component count and complexity, improves reliability, and optimizes efficiency by eliminating the need for external bias supplies, while maintaining flexibility for higher power applications.
Implementation Method 1
The transformer has a primary winding and a secondary winding. The primary side circuit is configured to operably couple a first signal to the primary winding of the transformer. The secondary side circuit is configured to provide, in response to the first signal coupled from the primary winding to the secondary winding, a second signal
Implementation Method 2
the secondary bias circuit comprises a storage capacitor that is configured to accumulate voltage when the secondary side circuit is providing the primary bias
Data Source
AI summary
A drive circuit comprises a transformer, a primary side circuit communicating with a primary winding of the transformer, and a secondary side circuit communicating with a secondary winding of the transformer. The primary side circuit couples to a primary side supply voltage and to an input signal and couples a first signal to the primary winding. The secondary side circuit communicates with the semiconductor switch and provides, responsive to the first signal, a second signal to control the semiconductor switch, comprising at least one of a primary bias and a secondary bias. For a first gate charge level range, the secondary side circuit provides the primary bias. For a second gate charge level range greater than the first range, the secondary side circuit is controlled by a secondary bias circuit comprising a storage capacitor configured to accumulate voltage when the secondary side circuit is providing the primary bias.