Parallel Power Transistor Gate Driving with Individual Gate Voltages
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Solution Overview
Problem
In semiconductor devices with parallel power transistors, the use of common gate voltage is limited by the short-circuit tolerance of IGBTs, restricting MOSFET characteristic improvement, leading to increased component count, circuit scale, and cost, as well as performance degradation due to varying transfer delays in separate drive circuits.
Innovation Solution
A semiconductor device with first and second power transistors connected in parallel, driven by individual gate voltages using a common drive circuit with separate amplifiers for each transistor, allowing for distinct power voltages and reducing transfer delay variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate drive circuits are prepared for each power transistor, then individual gate voltage control is achieved, but the number of components and circuit scale increase
Solution Approach 1:
The patent merges the drive circuit functionality into a single shared unit that controls multiple power transistors. The drive circuit generates a common drive signal that is then distributed to multiple amplifiers, each responsible for amplifying the signal to the appropriate gate voltage level for its associated transistor. This consolidation reduces the overall circuit scale while maintaining individual control capability.
Solution Approach 2:
The drive circuit is designed with universal functionality to control multiple types of power transistors (MOSFETs and IGBTs) with different gate voltage requirements. It generates a single drive signal that can be adaptively amplified by different amplifiers to match the specific needs of each transistor type, making the drive circuit applicable to various transistor configurations.
2Productivity
If separate drive circuits with different power voltages are used, then characteristic improvement is achieved, but transfer delay variation increases
Solution Approach 1:
The patent segments the voltage amplification function into separate amplifiers for different transistor types. Each amplifier is optimized for its specific transistor's gate voltage requirements, allowing characteristic improvement while maintaining synchronized drive signals from a common source to minimize transfer delay variation.
Solution Approach 2:
The drive circuit acts as an intermediary that generates a unified drive signal, which is then processed by individual amplifiers. This intermediary approach ensures that all transistors receive their appropriate gate voltages through a coordinated system, reducing transfer delay variation while achieving characteristic improvement.
3Device complexity
If common gate voltage is used for driving power transistors, then circuit simplicity is maintained, but MOSFET characteristic improvement is limited
Solution Approach 1:
The patent applies local quality by providing customized gate voltage amplification for different transistor types. While the drive circuit maintains a unified structure, each amplifier is tailored to the specific requirements of its associated transistors, enabling MOSFET characteristic improvement without significantly increasing overall circuit complexity.
Data Source
AI summary
A semiconductor device includes: first and second power transistors connected in parallel with each other and having different saturated currents; and a gate driver driving the first and second power transistors with individual gate voltages, respectively, the gate driver includes a drive circuit receiving an input signal and outputting a drive signal, a first amplifier amplifying the drive signal in accordance with first power voltage and supplying the amplified drive signal to a gate of the first power transistor, and a second amplifier amplifying the drive signal in accordance with second power voltage different from the first power voltage and supplying the amplified drive signal to a gate of the second power transistor.