Voltage Regulator Reverse Current Protection
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Solution Overview
Problem
Conventional voltage regulators with reverse-current prevention functions experience slow circuit response speed, leading to delayed switching signals and overshoot at the output terminal during sharp source voltage fluctuations, which can cause reverse current flow from the VDD terminal to the output terminal.
Innovation Solution
Incorporating a source voltage fluctuation detecting circuit within the comparison circuit to increase the current through the constant current circuit, allowing for faster switching of the substrate potential of the Pch transistor in response to source voltage fluctuations, thereby preventing reverse current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the comparison circuit uses a conventional constant current circuit to limit consumption current, then the reverse current is minimized, but the circuit response speed becomes slow causing delayed switching signals during sharp voltage fluctuations
Solution Approach 1:
The patent applies dynamics by making the constant current circuit's current value changeable based on operating conditions. The circuit switches between a first constant current value (lower) during normal operation to minimize reverse current, and a second constant current value (higher) during voltage fluctuations to improve response speed. This dynamic adjustment resolves the contradiction between minimizing reverse current and maintaining fast response speed.
Solution Approach 2:
The patent changes the current parameter of the constant current circuit based on the operating state. By detecting voltage fluctuations and adjusting the constant current value accordingly, the system optimizes both reverse current minimization and response speed. The parameter change allows the circuit to adapt to different conditions, achieving both low reverse current during stability and fast response during fluctuations.
2Loss of energy
If the circuit response speed is slow due to minimized reverse current, then energy loss is reduced, but overshoot occurs at the output terminal during sharp source voltage fluctuations
Solution Approach 1:
The dynamic adjustment of the constant current circuit's current value prevents overshoot by increasing the current during voltage fluctuations. This faster response ensures the switching signals are generated promptly, maintaining output voltage stability. During normal operation, the lower current minimizes reverse current, thus resolving the contradiction between energy loss and reliability.
Solution Approach 2:
The patent uses feedback by detecting the source voltage and comparing it with the output voltage to identify voltage fluctuations. This feedback mechanism triggers the adjustment of the constant current value, ensuring the circuit responds appropriately to maintain output stability while minimizing reverse current during normal operation.
3Use of energy by moving object
If the constant current circuit limits consumption current to minimize reverse current, then energy efficiency is improved, but the switching signal delay causes current flow through inter-substrate parasitic diode
Solution Approach 1:
The patent dynamically adjusts the constant current value to prevent parasitic diode current. During voltage fluctuations, the higher current ensures rapid switching signal generation, preventing the conditions that would cause parasitic diode conduction. During normal operation, the lower current maintains energy efficiency. This dynamic approach resolves the contradiction between energy usage and harmful factor generation.
Solution Approach 2:
The patent applies preliminary anti-action by detecting voltage fluctuations before they cause significant parasitic diode current flow. The circuit proactively increases the constant current value in response to detected fluctuations, preventing the harmful effect from occurring in the first place, while maintaining low current during normal conditions for energy efficiency.
Data Source
AI summary
There is provided a voltage regulator equipped with a reverse-current prevention function capable of ensuring safe performance without causing a large overshoot at an output terminal against a sharp fluctuation in source voltage. The voltage regulator provides a source voltage fluctuation detecting circuit for detecting a fluctuation in source voltage in a comparison circuit for comparing the source voltage with output voltage so that when the source voltage rises sharply, the current through constant current circuits for limiting the consumption current of the comparison circuit will be increased to improve the response characteristics.