Constant Power Control Circuit for High-Voltage Switching Safety
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Solution Overview
Problem
High-voltage power switching devices face increased power and current when the output voltage drops, leading to unsafe operating conditions due to the increased voltage difference between input and output voltages, causing them to exceed their safe operating area.
Innovation Solution
A constant power control circuit that generates a limitation current based on the voltage difference between the input and output voltages, using a voltage generator circuit and driving circuit to adjust the duty cycle of control signals and convert voltages to manage the current, ensuring the device operates within safe limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output voltage drops due to abnormal load operation, then the voltage difference between input and output voltage increases, but the current and power of the high-voltage power switching device increase excessively causing unsafe operating conditions
Solution Approach 1:
The patent implements a feedback mechanism where the controller monitors the output voltage and detects voltage drops. When abnormal conditions are detected, the controller adjusts the driving signal to limit the current through the power switching device. This closed-loop feedback ensures the device operates within safe power limits even when load conditions change abnormally.
Solution Approach 2:
The patent dynamically adjusts the driving signal characteristics based on real-time voltage conditions. The controller modifies the duty cycle or frequency of the driving signal in response to detected voltage drops, enabling the system to adapt its power delivery characteristics dynamically to maintain safe operating conditions while responding to load changes.
2Reliability
If the output voltage drops, then the voltage difference increases, but the current through the power switching device increases causing unsafe operating conditions
Solution Approach 1:
The controller continuously monitors output voltage and uses feedback control to adjust the driving signal. When voltage drops indicate abnormal load operation, the feedback mechanism triggers current limiting by modifying the driving signal parameters, thereby preventing excessive current flow while maintaining system reliability.
Solution Approach 2:
The patent applies preliminary anti-action by proactively limiting current before excessive power dissipation can occur. The controller detects early signs of abnormal operation through voltage monitoring and preemptively adjusts the driving signal to prevent the current from reaching dangerous levels, rather than reacting after the problem fully develops.
Data Source
AI summary
A constant power control circuit driving an external device receiving an input voltage and generating an output voltage is provided. A first conversion circuit converts the voltage difference between the input voltage and the output voltage to generate a charge current. An energy storage circuit is charged during a charging period by the charge current to provide a stored voltage. The charging period is terminated in response to the stored voltage reaching a predetermined voltage. A control circuit adjusts a control signal according to a length of the charging period. A second conversion circuit generates a counting voltage according to the control signal. The counting voltage is inversely proportional to the voltage difference. A third conversion circuit converts the counting voltage into a limitation current. A driving circuit compares the setting current and the limitation current to generate a driving signal and send it to the external device.