Semiconductor Integrated Circuit Overvoltage Protection
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Solution Overview
Problem
In semiconductor integrated circuit devices with limited external terminals, conventional methods to prevent breakdown due to short circuits between adjacent terminals are impractical, as they require additional terminals to function effectively.
Innovation Solution
The integration of an overvoltage protection circuit that connects the second external terminal to an overvoltage protection circuit, masking the control signal for the transistor when a predetermined threshold is reached, preventing excessive current flow and transistor breakdown without the need for an extra external terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-connected terminal is used as an external terminal adjacent to a high withstand voltage terminal to prevent breakdown, then reliability is improved, but device complexity increases due to requiring additional terminals
Solution Approach 1:
The patent merges the protection function with an existing functional terminal (the second external terminal that outputs control signals). Instead of adding a separate non-connected terminal, the invention integrates overvoltage protection circuitry into the existing terminal structure, allowing the same terminal to serve both signal output and protection functions.
Solution Approach 2:
The patent introduces an intermediary overvoltage detection circuit that monitors the voltage at the second external terminal and intervenes when overvoltage conditions are detected. This intermediary circuit masks the control signal to prevent excessive current flow, acting as a mediator between the external terminal and the internal transistor without requiring additional external terminals.
2Reliability
If additional external terminals are provided to prevent short circuit breakdown, then reliability is improved, but mounting space increases
Solution Approach 1:
The protection function is merged with existing external terminals, eliminating the need for additional terminals that would increase mounting space. The second external terminal continues to serve its primary function of outputting control signals while simultaneously providing overvoltage protection feedback.
Solution Approach 2:
The second external terminal is designed to serve multiple functions: outputting control signals for transistor operation and providing overvoltage protection feedback. This multi-functionality reduces the total number of external terminals required, thereby reducing mounting space while maintaining reliability.
3Area of stationary object
If the number of external terminals is minimized to reduce mounting space, then area is reduced, but reliability deteriorates due to increased short circuit risk
Solution Approach 1:
An intermediary overvoltage detection circuit is introduced that monitors the voltage at the second external terminal and intervenes when overvoltage conditions are detected. This intermediary mechanism provides active protection against short circuits between adjacent terminals without requiring additional external terminals, thus maintaining both compact area and high reliability.
Solution Approach 2:
The patent implements a feedback mechanism where the voltage at the second external terminal is monitored and fed back to the overvoltage protection circuit. When the voltage exceeds a predetermined threshold, the feedback signal triggers masking of the control signal to prevent excessive current flow, enabling active protection with minimal terminal count.
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
This configuration effectively prevents transistor breakdown and overheating during short circuits between high and low voltage terminals, ensuring device functionality with minimal external terminals, thus reducing the risk of short circuits and maintaining device integrity.
Implementation Method 1
an overvoltage protection circuit masking a control signal for turning on and off the transistor so that, when a voltage at the second terminal reaches a predetermined threshold, the transistor is kept off
Data Source
AI summary
In a semiconductor integrated circuit device of the invention, a plurality of external terminals include: a first external terminal (VCC, U, V and W terminals in the FIGURE) receiving a higher voltage than the other external terminals; and a second external terminal (FG terminal in the FIGURE) arranged adjacent to the first external terminal as one of the other external terminals, the second external terminal feeding out, from one end of a transistor Q1, a control pulse signal corresponding to the turning on and off of the transistor Q1, and the second external terminal is connected to an overvoltage protection circuit (consisting of R1, R2, Q2 and AND) that masks a control signal for turning on and off the transistor Q1 so that, when a voltage at the second external terminal reaches a predetermined threshold, the transistor Q1 is kept off all the time. In this way, it is possible to prevent, without the need for an extra external terminal, breakdown in case of a short circuit between adjacent external terminals.