LDO Regulator Inrush Current Feedback for Supply Voltage Stability
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Solution Overview
Problem
Inrush currents drawn by low drop-out voltage regulators can cause variations in power supply voltage, leading to malfunctions such as failure of voltage converters in electronic devices.
Innovation Solution
A device comprising N low drop-out voltage regulators, a first circuit to deliver set-point voltages proportional to a reference current modulated based on the sum of inrush currents, and a second circuit to adjust the current delivered to the regulators, ensuring the current increases in absolute value as the sum of inrush currents decreases, thereby limiting the maximum inrush current and stabilizing the power supply voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If regulators are powered with the same power supply voltage without current control, then the power supply voltage varies due to inrush currents, but the device complexity remains low
Solution Approach 1:
The patent implements a feedback mechanism where the inrush current detection circuit monitors the sum of inrush currents from N regulators and feeds this information back to the current delivery circuit. This feedback loop enables automatic modulation of the reference current to maintain power supply voltage stability without requiring complex external control systems.
Solution Approach 2:
The system achieves self-regulation through the inrush current detection circuit that automatically detects and responds to inrush current variations. The detection circuit and current modulation mechanism work autonomously to limit inrush currents and stabilize voltage without external intervention, making the system self-sufficient in managing power supply stability.
2Reliability
If inrush current is limited through circuit modification, then power supply voltage stability improves, but the device complexity increases
Solution Approach 1:
The patent introduces an intermediary inrush current detection circuit that acts as a mediator between the power supply voltage and the regulators. This detection circuit monitors voltage variations and inrush currents, translating them into control signals that modulate the reference current, thereby preventing converter malfunctions without directly modifying the regulator structure.
Solution Approach 2:
The system performs preliminary action by detecting inrush currents before they cause harmful voltage variations. The inrush current detection circuit proactively identifies current surges and pre-adjusts the reference current modulation to prevent malfunctions, rather than reacting after damage occurs.
3Area of stationary object
If capacitor size is reduced to decrease device surface area, then the device footprint decreases, but the ability to handle inrush current variations may be compromised
Solution Approach 1:
The patent changes the operational parameters of the system by dynamically modulating the reference current based on detected inrush currents. This parameter modulation allows the system to maintain reliable inrush current handling with smaller capacitors, as the active current control compensates for the reduced energy storage capacity of smaller capacitors.
Data Source
AI summary
The present disclosure relates to a device comprising: N low drop-out voltage regulators, N being an integer greater than or equal to 1; a first circuit configured to deliver N set-point voltages to the N regulators which are proportional to the same first current; and a second circuit configured to deliver the first current, wherein the first current is proportional to a reference current modulated based on a sum of the inrush currents of the N regulators.