Voltage Regulator Leakage Current Control Circuit
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Solution Overview
Problem
Existing voltage regulators experience an increase in output voltage due to leakage current from PMOS transistors under high temperature and light load conditions, leading to instability in output voltage regulation.
Innovation Solution
Incorporation of a leakage current control circuit using an NMOS transistor connected to the output terminal, which redirects the leakage current to prevent output voltage increases by causing it to flow through the NMOS transistor when the output voltage rises.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PMOS transistor is used as the output transistor in a voltage regulator, then the voltage regulator can achieve good regulation performance under normal conditions, but under high temperature and light load conditions, leakage current from the PMOS transistor causes output voltage to increase
Solution Approach 1:
The patent introduces a leakage current control circuit that detects the harmful leakage current from the PMOS transistor and redirects it through a dedicated path (using NMOS transistor 123 and resistor 113) to ground. This converts the harmful leakage current into a controlled current path, preventing it from causing output voltage increase while maintaining the beneficial output transistor functionality.
Solution Approach 2:
The patent introduces an intermediary leakage current control circuit between the PMOS output transistor and the output terminal. This intermediary circuit, comprising NMOS transistor 123 and resistor 113, mediates the leakage current by providing an alternative path, thus isolating the harmful effect from the output while preserving the main transistor's voltage regulation function.
2Device complexity
If the leakage current is allowed to flow normally, then the circuit structure remains simple, but the output voltage increases under light load conditions
Solution Approach 1:
The patent segments the current path by introducing a separate leakage current control circuit that is distinct from the main voltage regulation path. The leakage current is separated and directed through NMOS transistor 123 and resistor 113 to ground, while the main regulation function continues through the original PMOS transistor 111, thus managing complexity through functional segmentation.
3Reliability
If the NMOS transistor is added to control leakage current, then output voltage stability is improved under light load conditions, but the device complexity increases
Solution Approach 1:
The leakage current control circuit is designed to operate automatically based on the operating conditions. The NMOS transistor 123 is activated when leakage current becomes significant (high temperature and light load conditions), and remains inactive during normal operation. This self-service mechanism provides voltage stability improvement only when needed, minimizing the impact of added 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 prevents output voltage increases caused by leakage currents, ensuring stable voltage regulation even under high temperature and light load conditions, and can operate in other scenarios where leakage currents occur.
Implementation Method 1
the leakage current control circuit causes the leakage current to flow through the NMOS transistor, to thereby prevent an increase in output voltage
Data Source
AI summary
Provided is a voltage regulator capable of preventing an output voltage from being increased even when a leakage current flows in an output transistor. The voltage regulator includes a leakage current control circuit. The leakage current control circuit includes an NMOS transistor connected to an output terminal of the voltage regulator. When the output voltage of the voltage regulator increases due to the leakage current of the output transistor, the leakage current control circuit causes the leakage current to flow through the NMOS transistor, to thereby prevent an increase in output voltage.