Dual Current-Limiting Power Supply Control for Inrush Suppression
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Solution Overview
Problem
Conventional methods for suppressing inrush current in power supply systems require large space for heat dissipation and are temperature-sensitive, leading to inefficiencies and reliability issues.
Innovation Solution
A power supply control device with a current limiting module comprising parallel first and second current limiting units, controlled by a unit to manage inrush currents during startup and power fluctuations, using transistors and resistors to regulate current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermistor (current limiting resistor) is connected in series to limit inrush current, then inrush current is suppressed, but large space is required for heat dissipation and the device becomes temperature-sensitive
Solution Approach 1:
The patent introduces a MOS tube as an intermediary current limiting component between the power source and the circuit. The MOS tube acts as a controllable resistance that limits inrush current during startup, replacing the traditional thermistor. This intermediary device provides precise current control without the heat dissipation and temperature sensitivity issues of resistive components.
Solution Approach 2:
The patent dynamically changes the resistance parameter of the current limiting component by using a MOS tube whose resistance can be controlled through gate voltage. During startup, the MOS tube presents high resistance to limit inrush current, then gradually reduces resistance as the circuit stabilizes. This parameter change approach eliminates the need for large heat dissipation space required by fixed resistive components.
2Reliability
If a thermistor is used for current limiting, then inrush current is limited, but the device is easily affected by temperature changes
Solution Approach 1:
The patent replaces the passive thermal-based current limiting mechanism (thermistor that relies on temperature-dependent resistance) with an active electronic control system using a MOS tube. The MOS tube's resistance is controlled by electrical signals rather than temperature changes, eliminating the temperature sensitivity inherent in thermistor-based solutions.
Solution Approach 2:
The patent implements a feedback control mechanism where the microcontroller monitors circuit conditions and adjusts the MOS tube gate voltage accordingly. This closed-loop control ensures stable current limiting performance regardless of temperature variations, as the system actively compensates for environmental changes rather than passively responding to them.
3Power
If large electrolytic capacitors are used in high-power power supply, then power supply capability is enhanced, but large peak current is generated during startup and ride-through
Solution Approach 1:
The patent applies preliminary action by enabling the MOS tube to limit current before the large electrolytic capacitors fully charge during startup. The MOS tube is activated in advance to control the charging current, preventing peak current generation while still allowing the capacitors to charge to the required level for high-power operation.
Solution Approach 2:
The MOS tube serves as an intermediary device between the power source and the large electrolytic capacitors. It mediates the charging process by providing controlled current flow, allowing the capacitors to charge without generating harmful peak currents. This intermediary approach preserves the power supply capability provided by large capacitors while eliminating their harmful peak current effect.
Data Source
AI summary
A power supply device, a power supply control device and a control method thereof are provided. The power supply control device is electrically connected to a power source configured to provide power to a post-stage circuit of the power supply control device, and the power supply control device includes a current limiting module and a control unit. The current limiting module is electrically connected to the power source and the post-stage circuit and includes first and second current limiting units electrically connected in parallel. The first current limiting unit is configured to limit an inrush current generated during startup of the post-stage circuit, and the second current limiting unit is configured to limit an inrush current generated during a fluctuation of the power source. The control unit is electrically connected to the current limiting module and is configured to control the first and second current limiting units.