Power Semiconductor Gate Capacitance for Noise-Immune Ignition Control
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Solution Overview
Problem
Conventional semiconductor devices in ignition systems for automobile internal-combustion engines face noise immunity issues due to external noise, leading to potential malfunctions and incorrect ignition timing, which can be exacerbated by the increased chip size and cost associated with using large capacitance capacitors to enhance noise immunity.
Innovation Solution
A semiconductor device with a power semiconductor chip, a threshold setting unit, and a breaker circuit that utilizes the gate capacitance as an auxiliary power supply to stabilize the voltage signal during sudden drops in the control signal, preventing malfunctions and erroneous ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large capacitance capacitors are used to enhance noise immunity, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The invention utilizes the gate capacitance of the power semiconductor chip itself as an auxiliary power supply for the threshold setting unit. The gate capacitance, which is inherently present in the power semiconductor chip, is repurposed to provide backup power during voltage drops, eliminating the need for external large capacitance capacitors. This self-service approach maintains noise immunity while avoiding additional components that would increase chip size and complexity.
Solution Approach 2:
The gate capacitance of the power semiconductor chip serves dual functions: its primary function in switching operation and its secondary function as an auxiliary power supply for the threshold setting unit. By making the gate capacitance multi-functional, the invention eliminates the need for separate large capacitance capacitors, thereby maintaining reliability without increasing device complexity.
2Reliability
If large capacitance capacitors are used to enhance noise immunity, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The invention utilizes the gate capacitance of the power semiconductor chip itself as an auxiliary power supply for the threshold setting unit. The gate capacitance, which is inherently present in the power semiconductor chip, is repurposed to provide backup power during voltage drops, eliminating the need for external large capacitance capacitors. This self-service approach maintains noise immunity while avoiding additional components that would increase chip size and complexity.
Solution Approach 2:
Instead of using expensive large capacitance capacitors, the invention leverages the existing gate capacitance of the power semiconductor chip, which is already part of the device structure. This approach uses a resource that is already available at no additional cost, thereby reducing manufacturing costs while maintaining the required noise immunity.
3Device complexity
If conventional threshold setting units are used, then device simplicity is maintained, but noise immunity deteriorates during voltage drops
Solution Approach 1:
The invention utilizes the gate capacitance of the power semiconductor chip itself as an auxiliary power supply for the threshold setting unit. The gate capacitance, which is inherently present in the power semiconductor chip, is repurposed to provide backup power during voltage drops, eliminating the need for external large capacitance capacitors. This self-service approach maintains noise immunity while avoiding additional components that would increase chip size and complexity.
Solution Approach 2:
The gate capacitance acts as an intermediary energy storage element between the control signal voltage and the threshold setting unit. During voltage drops, the gate capacitance mediates by providing backup power to the threshold setting unit, preventing malfunction without requiring direct connection to external large capacitance capacitors.
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 effectively enhances noise immunity by maintaining stable operation during voltage fluctuations, preventing malfunctions and ensuring accurate ignition timing without the need for large capacitance capacitors, thus reducing costs and chip size.
Implementation Method 1
the feed circuit uses, as an auxiliary power supply, an electric charge stored in gate capacitance of the power semiconductor chip
Data Source
AI summary
A semiconductor device includes a power semiconductor chip, a threshold setting unit and a breaker circuit. The power semiconductor chip is connected between an output terminal and an earth terminal, and is configured to be turned on or off according to a potential at a gate terminal thereof. The threshold setting unit outputs an interrupt signal upon detecting that a voltage of a control signal received at an input terminal is lower than a predetermined voltage. The breaker circuit is connected between the gate terminal and the earth terminal, and switches on upon receiving the interrupt signal to thereby turn off the power semiconductor chip. The threshold setting unit includes a feed circuit that is configured to supply an electric charge stored in gate capacitance of the power semiconductor chip to the threshold setting unit responsive to a sudden drop of the voltage of the control signal.