Synchronous Rectifier Protection in Intermittent Power Supplies
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional power supply devices using synchronous rectifier elements face increased loss and potential damage due to the failure of the drive circuit, leading to body diode conduction when control signals are not supplied to MOS transistors.
Innovation Solution
A power supply device incorporating an intermittent voltage generation circuit, rectifying and smoothing circuit, synchronous rectifier element drive circuit, abnormality detection circuit, load current detection circuit, and protection circuit to detect and mitigate abnormalities in the synchronous rectifier element, thereby preventing damage and reducing loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a synchronous rectifier element is used to reduce loss, then energy efficiency is improved, but the risk of body diode conduction and increased loss due to drive circuit failure increases
Solution Approach 1:
The abnormality detection circuit proactively monitors the drive circuit status before body diode conduction occurs. By detecting abnormalities in advance (such as drive signal anomalies or MOS transistor gate voltage issues), the system can trigger protective actions to prevent the harmful body diode conduction state, thus maintaining the reliability advantage while preserving energy efficiency.
Solution Approach 2:
The protection circuit implements a feedback mechanism where the abnormality detection circuit continuously monitors the synchronous rectifier element status and feeds this information back to the protection circuit. When abnormalities are detected, the protection circuit adjusts the drive signal or disables the synchronous rectifier element to prevent body diode conduction, creating a closed-loop control system that maintains both reliability and energy efficiency.
2Reliability
If an abnormality detection and protection circuit is added, then synchronous rectifier element reliability is improved, but device complexity increases
Solution Approach 1:
The abnormality detection circuit is designed to monitor multiple parameters (drive signal status, gate voltage, current flow) using a unified detection mechanism. The protection circuit serves multiple functions by being able to respond to different abnormality types with appropriate protective actions. This multi-functionality reduces the need for separate dedicated circuits for each monitoring function, thereby limiting the increase in device complexity while maintaining comprehensive reliability protection.
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 effectively detects and protects the synchronous rectifier element, preventing damage and reducing loss by adjusting the load current and generating alarm signals when abnormalities occur.
Implementation Method 1
smooths the intermittent voltage by a capacitor
Data Source
AI summary
A power supply device includes an intermittent voltage generation circuit, a rectifying and smoothing circuit, a synchronous rectifier element drive circuit, an abnormality detection circuit, a load current detection circuit, and a protection circuit. The intermittent voltage generation circuit generates an intermittent voltage from an input voltage from an external power supply by a switching element that is repeatedly turned on and off. The rectifying and smoothing circuit rectifies the intermittent voltage by a synchronous rectifier element that is turned on and off in synchronization with on and off of the switching element, smooths the intermittent voltage by a capacitor, and supplies the intermittent voltage to a load. The synchronous rectifier element drive circuit supplies a control signal for turning on and off the synchronous rectifier element to a control terminal of the synchronous rectifier element. The abnormality detection circuit detects an abnormality in the synchronous rectifier element drive circuit. The load current detection circuit detects a load current that is a current of the load supplied by the rectifying and smoothing circuit. The protection circuit performs a protection operation on the basis of a detection result of the abnormality detection circuit and a detection result of the load current detection circuit.