Semiconductor Regulator Circuit Current Limiting
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Solution Overview
Problem
In semiconductor integrated circuits with regulator circuits, it is challenging to appropriately control current flowing through the output transistor to prevent overcurrent and ensure effective current limiting, especially when the operating range of the input voltage is wide and the input-output potential difference is small, leading to variations in limited current values and reduced effectiveness of current-limiting operations.
Innovation Solution
The semiconductor integrated circuit incorporates a current-limiting circuit with a replica transistor and a potential regulation circuit to equalize the drain potential of the output transistor with that of the replica transistor, using a voltage follower or current mirror circuit to maintain a consistent drain-source voltage, thereby ensuring appropriate current limiting by setting the mirror ratio of currents between the output and replica transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the operating range of input voltage is wide and input-output potential difference is small, then the regulator circuit can operate under more conditions, but the current limiting effectiveness deteriorates and limited current values vary
Solution Approach 1:
The patent applies equipotentiality by equalizing the drain potentials of the output transistor and replica transistor through the potential regulation circuit. This ensures that both transistors operate at the same potential level, making the current mirror relationship accurate and stable regardless of input voltage variations or small input-output potential differences, thereby maintaining effective current limiting across a wide operating range
2Device complexity
If conventional current limiting circuits are used without drain potential equalization, then the circuit structure is simple, but the current limiting effectiveness deteriorates under varying input voltage conditions
Solution Approach 1:
The patent introduces a potential regulation circuit as an intermediary component between the replica transistor and output transistor. This intermediary circuit actively equalizes the drain potentials of both transistors, ensuring accurate current mirroring and reliable current limiting without significantly complicating the overall circuit structure
3Ease of operation
If the drain potential of output transistor and replica transistor are not equalized, then the circuit operation is simpler, but the limited current values vary and current limiting becomes ineffective
Solution Approach 1:
The potential regulation circuit implements feedback control by continuously monitoring and adjusting the drain potential of the output transistor to match that of the replica transistor. This feedback mechanism ensures that the current mirror relationship remains accurate, maintaining consistent limited current values and effective current limiting across varying operating conditions
Data Source
AI summary
A semiconductor integrated circuit includes an output transistor, an error amplifier, a replica transistor, a current-limiting circuit, and a potential regulation circuit. The output transistor is electrically connected between a power supply-side first node and an output-side second node. The replica transistor is electrically connected between the first node and a fourth node. The replica transistor constitutes a circuit that is configured to operate to correspond to the output transistor. The current-limiting circuit has an input node, that is electrically connected to a fifth node between the fourth node and a first current source, and an output node that is electrically connected to a gate of the output transistor and a gate of the replica transistor. The potential regulation circuit is electrically connected to the second node and the fourth node.