Bidirectional Current Control Circuit for Fuse-Free Peak Limiting
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Solution Overview
Problem
Existing circuits fail to effectively limit current levels in different current directions with minimal circuit effort, leading to potential damage from peak currents and increased wear due to high currents, and require replacement of melted fuses.
Innovation Solution
A method and circuit using two transistor switches with short-circuited source terminals, controlled by analog transistor controllers, measure and regulate current flow in both directions, allowing continuous and real-time adjustment to prevent peak currents by linear control, replacing electromechanical fuses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuses are used to prevent damage from peak currents, then device protection is improved, but circuit wear increases and maintenance effort increases due to fuse replacement
Solution Approach 1:
The patent replaces the mechanical fuse system with an electronic current control system using transistor switches (Q1, Q2) and control electronics. The transistors are controlled to limit current through the load, eliminating the need for mechanical fuses that require replacement after blowing. This substitution provides continuous current protection without maintenance intervention.
2Manufacturing precision
If current limiting is implemented for both current directions, then current control precision is improved, but device complexity increases
Solution Approach 1:
The patent employs asymmetric current control where transistor Q1 limits current in one direction and transistor Q2 limits current in the opposite direction. Each transistor is controlled by its own controller (31, 32) with independent target current settings. This asymmetric approach allows precise control for each current direction while maintaining circuit simplicity through dedicated control paths.
3Manufacturing precision
If analog transistor controllers are used for continuous current regulation, then current control precision is improved, but device complexity increases compared to digital control
Solution Approach 1:
The patent implements feedback control where controllers (31, 32) continuously monitor the actual current through sensors and adjust the gate voltages of transistors (Q1, Q2) accordingly. The controllers compare the measured current with target current values and dynamically regulate the transistor conduction to maintain precise current control. This closed-loop feedback mechanism enables continuous analog regulation while keeping the control architecture manageable through dedicated control paths.
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 provides safe and effective current path definition and short-circuit current limitation, minimizing circuit wear and eliminating the need for fuse replacement, while allowing different current directions with minimal circuit effort.
Implementation Method 1
gate voltages at gate terminals of the transistor switches are set by analog transistor controllers associated to the transistor switches, thus regulating an actual current through the transistor switches
Implementation Method 2
the actual current is measured by a current measuring device between the transistor switches
Implementation Method 3
the source or emitter terminals of said transistor switches are electrically short-circuited
Data Source
AI summary
A current control circuit has a first and a second load component and/or generator component between which a current flows in a first or in a second current direction. Two transistor switches are connected in series between the first and the second load component and/or generator component. Source or emitter terminals of the transistor switches are electrically short-circuited. Gate voltages of the transistor switches are set by analog transistor controllers. A current measurement device measures an actual current between the transistor switches. A digital controller specifies a first target current for the first current direction and a second target current for the second current direction to the transistor controllers. Depending on the respective difference between the actual current and the target current, corresponding gate voltages for the transistor switches are set by the transistor controllers to control the actual current through the transistor switches.