IGBT Gate Drive Circuit With Switchable Current Capability
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Solution Overview
Problem
Intelligent power modules (IPMs) have fixed drive capability for semiconductor chips, requiring new development when the drive capability is excessively high or insufficient for the load, such as a motor.
Innovation Solution
A drive circuit for switching elements in IPMs that includes a constant current supply unit, signal level determination unit, and drive capability switching unit to adjust the current amount based on input signal levels, allowing flexible drive capability selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive capability of the MOS transistor is fixed to a constant current value, then the IPM structure is simple and reliable, but the adaptability to different load requirements deteriorates
Solution Approach 1:
The patent applies the Dynamics principle by making the drive capability adjustable rather than fixed. The constant current value supplied to the IGBT gate can be dynamically changed based on load requirements through switching between different current paths (first constant current path with current source 201 and second constant current path with current source 202), allowing the drive circuit to adapt to different operating conditions while maintaining circuit reliability.
Solution Approach 2:
The patent implements Parameter changes by varying the current amount supplied to the IGBT gate. Different current values (first constant current value from current source 201, second constant current value from current source 202) are used depending on the drive capability requirements. This allows the same IPM to serve multiple applications with different load characteristics without requiring new development.
2Ease of manufacture
If the drive capability is fixed in the IPM, then the manufacturing cost is reduced, but the productivity in terms of application flexibility deteriorates
Solution Approach 1:
The patent applies the Universality principle by designing the IPM with multi-functional drive capability. The drive circuit can operate in different modes (first drive capability with current source 201, second drive capability with current source 202) to accommodate various application requirements. This allows a single IPM design to serve multiple applications with different power conversion needs, eliminating the requirement for new development for each application while maintaining manufacturing simplicity.
3Manufacturing precision
If a new IPM is developed for each drive capability requirement, then the drive capability matches the load perfectly, but the development time and cost increase
Solution Approach 1:
The patent makes the drive capability dynamic and adjustable within the same IPM. By switching between different constant current sources (201 and 202) with different current values, the IPM can be configured to match different load requirements without requiring new development. This dynamic adjustment capability achieves precise drive capability matching while avoiding the time and cost of developing new IPMs for each application.
Solution Approach 2:
The patent changes the current parameter (constant current value) to match different drive capability requirements. The first constant current source (201) provides one current value, while the second constant current source (202) provides another current value. By selecting which current source to use, the IPM can be precisely matched to different load requirements without new development, achieving both precision and time efficiency.
Data Source
AI summary
A gate drive circuit, in order to cause an IGBT in a semiconductor elements to switch to the ON state according to the signal level of an input signal, includes a constant current supply unit configured to supply constant current to the gate of the IGBT, a switching signal input terminal to which a switching signal is input, a signal level determination unit configured to determine a signal level of the switching signal, and a drive capability switching unit configured to, by changing a current amount of constant current output from the constant current supply unit, based on a determination result in the signal level determination unit and a signal level of the input signal, switch the drive capability of the constant current supply unit.