Single Isolation Device for Feedback and Fault Detection
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Solution Overview
Problem
Conventional AC-DC power supplies require two digital signal processors and two isolation devices for feedback control and fault detection, increasing complexity and cost.
Innovation Solution
An isolated power supply using a single isolation device for both feedback control and fault detection, where the controller senses the output voltage and modifies the feedback signal based on a fault threshold slew rate, allowing for efficient fault detection and reduced component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two isolation devices are used (one for feedback control and one for fault detection), then reliability of fault detection is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines feedback control and fault detection functions into a single isolation device. The isolation device receives feedback signals from the secondary side and provides them to the controller, which simultaneously performs both feedback control and fault detection by analyzing the same isolated signal, eliminating the need for separate isolation devices for each function.
Solution Approach 2:
The single isolation device is designed to serve multiple functions: it provides electrical isolation for feedback control signals while also enabling fault detection through the same isolation pathway. The controller analyzes the isolated feedback signal to detect faults, making the isolation device universal for both control and protection functions.
2Measurement precision
If two digital signal processors are used (one for each converter stage), then control precision is improved, but device complexity and cost increase
Solution Approach 1:
The controller is designed to perform multiple control functions for both the PFC stage and DC-DC converter stage using a single digital signal processor. It receives feedback signals, processes them, and generates control signals for both converter stages, eliminating the need for separate controllers while maintaining control precision through integrated processing.
Solution Approach 2:
The patent merges the control functions of two separate digital signal processors into a single controller. The unified controller handles feedback processing, power factor correction control, and DC-DC converter control in one integrated unit, reducing component count while maintaining precise control through centralized processing.
3Device complexity
If a single isolation device is used for both feedback and fault detection, then device complexity is reduced, but reliability may deteriorate
Solution Approach 1:
The system uses feedback from the isolated signal to monitor system status. The controller continuously receives feedback signals through the isolation device and analyzes them for fault conditions, using the same feedback pathway for both normal operation monitoring and fault detection, ensuring reliable fault identification without additional isolation components.
Solution Approach 2:
The isolation device acts as an intermediary that transfers feedback signals from the secondary side to the primary side controller. The controller analyzes this intermediate signal for both control and fault detection purposes, using the isolation device as a mediator that enables both functions through its isolated signal transmission capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces the need for additional fault detection isolation components, simplifies circuit complexity, and lowers costs while providing effective feedback control and fault protection.
Implementation Method 1
a transformer having a primary winding and a secondary winding
Implementation Method 2
at least one power switch coupled to the primary winding of the transformer
Implementation Method 3
a feedback circuit coupled to the output terminal to sense the output voltage and compare the sensed output voltage to a voltage reference to define a feedback signal
Implementation Method 4
a fault detection circuit coupled between the output terminal and the feedback circuit to sense the output voltage, compare the sensed output voltage to a fault reference, and modify the feedback signal when the sensed output voltage exceeds the fault reference
Implementation Method 5
The controller is operable to control the power switch based on the feedback signal and to detect a fault condition when a slew rate of the feedback signal exceeds a fault threshold slew rate value
Data Source
AI summary
According to some aspects of the present disclosure, isolated power supplies and corresponding control methods are disclosed. Example isolated power supplies include a transformer, at least one power switch coupled to the transformer, a controller, an output terminal, and a feedback circuit coupled to the output terminal to sense the output voltage and compare the sensed output voltage to a voltage reference. The power supplies include a fault detection circuit to sense the output voltage, compare the sensed output voltage to a fault reference, and modify a feedback signal when the sensed output voltage exceeds the fault reference. The power supplies also include a single isolation device coupled between the feedback circuit and the controller. The controller is operable to control the power switch based on the feedback signal and to detect a fault condition when a slew rate of the feedback signal exceeds a fault threshold slew rate value.