High-Voltage MOSFET eFuse With Resettable Current Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High voltage DC electronic systems face protection challenges due to the limited availability, high cost, and replacement requirements of conventional high voltage DC fuses, which are not effectively addressing short circuits and malfunctions in applications like electric vehicles.
Innovation Solution
An electronic fuse (eFuse) is developed, utilizing a low 'on' resistance N-type MOSFET switch and a sense circuit to monitor and control high voltage load currents, tripping when exceeding a set threshold and allowing for reset without replacement, with temperature compensation to stabilize the sensing circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional high voltage DC fuses are used for protection, then current protection is provided, but the device cost and system cost increase significantly
Solution Approach 1:
The patent replaces the mechanical fuse system with an electronic control system using a MOSFET switch and sense circuit. The MOSFET acts as an electronically controlled switch that can be rapidly opened to stop current flow, eliminating the need for expensive high voltage DC fuses while maintaining protection functionality.
Solution Approach 2:
The patent uses a low voltage sense circuit to monitor and control the high voltage circuit. The sense circuit creates a low voltage copy or representation of the high voltage current conditions, allowing safe monitoring and control without directly exposing low voltage components to high voltage, thereby reducing overall system cost.
2Reliability
If conventional high voltage DC fuses are used for protection, then current protection is provided, but replacement costs and system downtime increase when the fuse blows
Solution Approach 1:
The MOSFET-based protection system can be rapidly reset by controlling the gate voltage, allowing the system to restore operation quickly after a fault condition is cleared. This self-reset capability eliminates the need for manual fuse replacement and reduces system downtime significantly.
Solution Approach 2:
The system continuously monitors current through the sense circuit before faults occur, allowing for preventive action or rapid response when thresholds are exceeded. This continuous monitoring enables faster protection response and quicker system recovery compared to passive fuse operation.
3Object-affected harmful factors
If a high voltage diode is used to protect the sensing circuit from high drain-to-source voltage, then the sensing circuit is protected, but temperature variability increases
Solution Approach 1:
The patent uses a programmable voltage reference that can be adjusted to compensate for temperature-induced voltage changes in the high voltage diode. By changing the reference voltage parameter based on temperature conditions, the system maintains accurate current sensing despite temperature variations caused by the protective diode.
Solution Approach 2:
The sense circuit incorporates feedback mechanisms that monitor the voltage drop across the MOSFET and adjust control signals accordingly. This feedback loop compensates for temperature variations in the protective diode, maintaining stable sensing operation across different temperature conditions.
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 eFuse provides effective current protection in high voltage applications, reducing system downtime and costs by allowing for self-reset and maintaining consistent performance across varying temperatures.
Implementation Method 1
A high voltage diode is used to protect the sensing circuit
Implementation Method 2
both temperature variabilities are corrected using either a positive or negative temperature compensated thermistor
Data Source
AI summary
An eFuse for use in high voltage applications is disclosed. In one embodiment, an apparatus includes a solid-state switch having source and drain terminals connected to switch a load current from a high voltage source through a high voltage load. The apparatus also includes a sense circuit that senses a voltage between the switch source and drain terminals and turns off the switch when the voltage exceeds a selected voltage level.