MOSFET Current-Mirror Voltage Protection for Common-Mode Fluctuations
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Solution Overview
Problem
Existing voltage protection circuits for electrical devices are inadequate in mitigating common-mode voltage fluctuations, which can exceed acceptable ranges and cause damage or unreliable operation during tests like bulk current injection, leading to increased costs due to the use of chokes for protection.
Innovation Solution
A voltage protection circuit utilizing a transceiver with MOSFETs and current mirrors that compares common-mode voltage to a reference voltage, sourcing or sinking current to stabilize the voltage within acceptable ranges, thereby preventing damage and maintaining device reliability without the need for additional chokes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chokes are used to protect electrical devices from common-mode voltage fluctuations, then device reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive chokes with a cost-effective protection circuit implemented using standard MOSFETs and current mirrors that can be manufactured using conventional semiconductor fabrication processes. The circuit uses readily available components and standard manufacturing techniques to achieve voltage protection without the high cost of choke-based solutions
Solution Approach 2:
The patent substitutes the mechanical/inductive choke-based voltage protection system with an electronic circuit implementation using MOSFETs and current mirrors. This electronic substitution eliminates the need for bulky inductive components while achieving the same voltage clamping and protection function through semiconductor devices and active circuit control
2Object-affected harmful factors
If chokes are used for voltage protection, then common-mode voltage fluctuations are mitigated, but device complexity increases
Solution Approach 1:
The patent extracts the voltage protection function from the main signal path by implementing it as a separate protection circuit that activates only when voltage thresholds are exceeded. The MOSFETs are configured to remain inactive during normal operation and only engage when common-mode voltage exceeds safe levels, thus protecting the main circuit without adding continuous complexity
Solution Approach 2:
The patent introduces current mirrors as intermediary elements that mediate between the voltage protection requirement and the main circuit operation. The current mirrors provide isolated current copying and control paths that enable voltage clamping functionality without directly interfering with the primary signal paths, thus reducing the impact on overall circuit complexity
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
Effectively protects electrical devices from common-mode voltage fluctuations by stabilizing voltages within safe ranges, reducing the risk of damage and improving reliability without the added cost of chokes, thus enhancing the cost-effectiveness of voltage protection.
Implementation Method 1
conducting current between the source terminal and a drain terminal of the MOSFET to turn on a current mirror when a difference between a value of the common-mode voltage and a value of the reference voltage exceeds a threshold
Data Source
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AI summary
A voltage protection circuit (300), includes: a first metal oxide semiconductor field effect transistor (MOSFET) (308) having a gate terminal coupled to a first node (384), a source terminal coupled to a second node (382), and a drain terminal coupled to a third node (388); a second MOSFET (310) having a gate terminal coupled to the first node (384), a source terminal coupled to the second node (382), and a drain terminal coupled to a fourth node (386); a first current mirror (304) coupled to the third node (388) and configured to couple to a fifth node (378), a sixth node (380) and a regulator supply (392); and a second current mirror (306) coupled to the fourth node (386), and configured to couple to the fifth node (378), the sixth node (380) and a ground node (390).