Overcurrent Control Circuit for Power Supply Voltage Overshoot
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Solution Overview
Problem
Traditional power supply systems experience voltage overshoot when recovering from short circuits or overcurrents, leading to potential damage to both the load and the circuit due to the operational amplifier's adjustment time causing an overshoot in output voltage.
Innovation Solution
A circuit for overcurrent control is introduced, featuring an auxiliary reference voltage generating circuit, a low-voltage follower circuit, and an error amplifier, which generates an amplified error signal using a dynamic reference voltage that adjusts by clamping the intermediate voltage when a short circuit or overcurrent occurs, preventing overshoot by allowing the reference voltage to increase slowly with the feedback signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the operational amplifier adjusts its output voltage quickly to a steady value, then the response speed is improved, but voltage overshoot occurs causing damage to the load and circuit
Solution Approach 1:
The patent applies preliminary anti-action by detecting the short circuit or overcurrent condition before normal operation resumes and preemptively adjusting the reference voltage to a lower value. This prevents the operational amplifier from generating excessive output voltage when the condition is recovered, thereby avoiding voltage overshoot and its harmful effects on the load and circuit.
Solution Approach 2:
The patent implements preliminary action by preparing the reference voltage in advance through the auxiliary reference voltage generating circuit and low-voltage follower circuit. When a short circuit or overcurrent occurs, the reference voltage is pre-adjusted to a safe level before the operational amplifier responds, ensuring that the output voltage increases gradually without overshooting when the fault condition is resolved.
2Stability of the object's composition
If the reference voltage is kept at a high value during normal operation, then the output voltage stability is improved, but the system cannot respond quickly to short circuit or overcurrent conditions
Solution Approach 1:
The patent applies dynamics by making the reference voltage adjustable rather than fixed. The auxiliary reference voltage generating circuit and low-voltage follower circuit enable the reference voltage to dynamically change based on system conditions: it maintains a high value (first threshold value) during normal operation for stability, and automatically lowers to a second threshold value when short circuit or overcurrent is detected, thus achieving both stability and protection reliability.
Solution Approach 2:
The patent implements parameter changes by modifying the reference voltage parameter according to system state. The low-voltage follower circuit compares the auxiliary reference voltage with the first threshold value and selects the appropriate level, allowing the reference voltage parameter to switch between high and low values, thereby maintaining output voltage stability during normal operation while ensuring protection reliability during fault conditions.
Data Source
AI summary
The present disclosure relates to a circuit and a method for overcurrent control and a power supply system including the same. When the system operates normally, a reference voltage has a constant value. When a short circuit or an overcurrent occurs at an output of the system, the reference voltage will be pulled down,. When the system is recovered from the short circuit or the overcurrent state, the reference voltage increases slowly up to a steady value. A feedback signal of an output voltage follows the reference voltage and increases slowly. Thus, an overshoot of the output voltage can be effectively eliminated to avoid damages to the system.