Linear Regulator Bias Control for High-Temperature Leakage Suppression
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Solution Overview
Problem
Existing linear regulators face challenges in suppressing output leakage current at high temperatures, which leads to increased circuit current consumption and reduced efficiency, especially in light-load conditions.
Innovation Solution
The linear regulator incorporates a load configured to draw a first leakage current from a common control terminal of the transistors, and a bias current adjuster that increases the bias current by the same amount as the leakage current when the transistor is turned on, effectively suppressing the output leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional linear regulator design is used, then circuit simplicity is maintained, but output leakage current increases at high temperatures
Solution Approach 1:
A load transistor is introduced as an intermediary component connected to the control terminal of the main transistor. This load transistor actively draws leakage current away from the control terminal, preventing it from flowing to the output. The load transistor acts as a mediator that intercepts and redirects the harmful leakage current path.
Solution Approach 2:
The bias current supplied to the load transistor is dynamically adjusted based on temperature conditions. At high temperatures where leakage current increases, the bias current to the load transistor is increased to enhance its leakage drawing capability. This parameter change allows the circuit to adaptively suppress temperature-dependent leakage effects.
2Use of energy by moving object
If light-load operation is implemented, then energy efficiency is improved, but output leakage current becomes more significant
Solution Approach 1:
The circuit employs feedback mechanisms where the load transistor's bias current is adjusted based on the operating conditions. During light-load operation, the feedback system increases the bias current to the load transistor, enhancing its ability to draw leakage current. This feedback control ensures that leakage suppression is dynamically matched to the load condition.
Solution Approach 2:
The harmful leakage current is extracted from the main signal path by routing it through the load transistor to ground. By separating the leakage current path from the output path, the leakage is removed from the harmful output current, allowing efficient light-load operation without leakage penalties.
3Object-generated harmful factors
If bias current is increased to suppress leakage, then leakage current is reduced, but circuit power consumption increases
Solution Approach 1:
The bias current supplied to the load transistor is made dynamic rather than fixed. The bias current adjusts automatically based on temperature and load conditions - increasing when leakage suppression is needed (high temperature or light-load) and decreasing when full suppression capability is not required (heavy-load or low-temperature conditions). This dynamic adjustment optimizes the trade-off between leakage suppression and power consumption.
Data Source
AI summary
A linear regulator includes: a first transistor of an N-channel type configured to be connected between an application terminal for an input terminal and an application terminal for a stabilized voltage; a second transistor of an N-channel type configure to, by forming a current mirror type output stage with the first transistor, generate an output current flowing in the first transistor by mirroring a bias current flowing in the second transistor itself; a feedback controller circuit configured to control the bias current according to the difference between a feedback voltage corresponding to the stabilized voltage and a predetermined reference voltage; and a load configured to draw a first leakage current from a control terminal common to the first and second transistors.