Isolated Power Supply State Detection Using Secondary Current and Temperature
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Solution Overview
Problem
Existing methods for detecting the operating state of power supplies, particularly isolated power supplies, rely heavily on the accuracy of primary and secondary control units, leading to high costs and challenges in meeting safety specifications like the Limited Power Supply (LPS) test specifications, especially when the rated output power approaches the LPS level.
Innovation Solution
A detecting method and apparatus that utilize a secondary circuit with a secondary current detecting unit, a temperature detecting unit, and a secondary controlling unit to independently determine the operating state of a power supply by comparing the current value with a preset threshold and using temperature values when the current value is below the threshold, reducing dependence on primary circuit accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the primary circuit is used to detect the operating state when the rated output power is far less than the LPS power level, then the power supply can meet the LPS test specifications, but the power detection accuracy is low
Solution Approach 1:
The patent implements dynamic switching between primary circuit detection and secondary circuit detection based on the rated output power level. When the rated output power is far less than the LPS power level, the primary circuit is used for detection. When the rated output power is close to the LPS power level, the secondary circuit is activated to provide accurate detection, thus dynamically adapting the detection method to the operating conditions.
Solution Approach 2:
The patent changes the detection parameters by switching between different detection circuits based on the power level. The primary circuit uses voltage detection while the secondary circuit uses current detection, changing the detection parameter from voltage to current when high accuracy is required, thereby resolving the contradiction between meeting LPS specifications and maintaining detection accuracy.
2Measurement precision
If the secondary control unit is used to detect the fluctuation of the output voltage to determine the output power, then the operating state can be determined, but the power supply cost increases due to high sampling accuracy requirements
Solution Approach 1:
The patent segments the detection function into two independent circuits: the primary circuit for basic detection and the secondary circuit for accurate detection. The secondary circuit includes a current detecting unit, voltage detecting unit, and controlling unit that work together to provide accurate power detection without requiring high sampling accuracy from a single control unit, thereby reducing cost while maintaining precision.
Solution Approach 2:
The patent introduces an intermediary secondary circuit that acts as a mediator between the primary circuit and the control system. The secondary circuit processes the detection signals and provides accurate power information to the controlling unit, reducing the sampling accuracy burden on the main control unit and thereby reducing overall system cost while maintaining detection accuracy.
3Reliability
If the current detecting unit of the secondary circuit is bypassed, then the power supply can meet LPS specifications when rated output power is far less than LPS level, but cannot meet LPS specifications when rated output power is close to LPS level
Solution Approach 1:
The patent implements dynamic adaptability by enabling the secondary circuit to be activated based on the rated output power level. When the rated output power is close to the LPS power level, the secondary circuit with its current detecting unit is activated to provide accurate detection for LPS compliance. The system dynamically adapts its detection capability to match the operational requirements.
Solution Approach 2:
The patent creates a universal detection system where the secondary circuit serves multiple functions: it can be used for accurate power detection when needed, and can have its current detecting unit bypassed when not required. This multi-functional design allows the same hardware to serve different detection needs across different power levels, enhancing versatility while maintaining LPS compliance.
Data Source
AI summary
The present application provides a detecting method of an operating state of a power supply and a detecting apparatus, where the power supply includes a primary circuit, a transformer and a secondary circuit. The secondary circuit includes a secondary current detecting unit, a temperature detecting unit and a secondary controlling unit. Firstly the secondary current detecting unit detects a current value of the secondary circuit, then the secondary controlling unit compares the current value of the secondary circuit with a preset current threshold. When the current value of the secondary circuit is less than or equal to the preset current threshold, the temperature detecting unit detects a temperature value of the power supply and the secondary controlling unit determines the operating state of the power supply according to the acquired temperature value of the power supply.