Adaptive Dead-Time Control for DC Converter Secondary Switching
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Solution Overview
Problem
Switch converters at high power levels face inefficiencies due to current flowing through the body diode of the secondary switch, causing power wastage when both switches are open, leading to potential short circuits and reduced performance.
Innovation Solution
Incorporating a high-pass filter and trigger circuit to detect switching transients and generate a trigger signal that allows the secondary switch to close independently of the primary switch control circuitry, reducing the delay and power consumption through the body diode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both the primary switch and secondary switch are opened to prevent short circuit, then safety is improved, but current flows through the body diode of the secondary switch causing power wastage
Solution Approach 1:
The patent applies preliminary action by detecting the switching transient edge of the primary switch through a high-pass filter and generating a trigger signal in advance. This trigger signal is sent to the secondary switch control circuitry to initiate closing of the secondary switch before the body diode conduction period begins, thereby eliminating the power wastage while maintaining safe operation
Solution Approach 2:
The patent uses feedback by monitoring the switching transient edge of the primary switch through a high-pass filter and using this information to generate a trigger signal. This closed-loop feedback mechanism ensures the secondary switch closes at the optimal moment, preventing body diode conduction and reducing power losses
2Reliability
If the secondary switch closes later to ensure safe operation, then reliability is improved, but power consumption increases due to extended body diode conduction
Solution Approach 1:
The system performs preliminary detection of the primary switch's transient edge and generates a trigger signal in advance, enabling the secondary switch to close at the precise optimal moment. This eliminates unnecessary delay and prevents extended body diode conduction, reducing power consumption while maintaining safety
Solution Approach 2:
The patent replaces the traditional mechanical/timed delay system with an electronic detection and trigger system. By using a high-pass filter to detect transient edges and generate trigger signals, the system achieves precise timing control that optimizes the switching moment, reducing power consumption compared to conventional delay-based approaches
3Device complexity
If a traditional control system is used to manage switch timing, then device complexity is reduced, but switching delay increases causing power wastage
Solution Approach 1:
The patent introduces a feedback mechanism where the high-pass filter detects the primary switch's transient edge and feeds this information back to generate a trigger signal for the secondary switch. This feedback loop eliminates switching delays by using real-time detection rather than predetermined delays, improving response time while adding minimal complexity
Solution Approach 2:
The high-pass filter acts as an intermediary component that detects the transient edge of the primary switch and translates it into a usable trigger signal. This intermediary element enables precise timing control without requiring complex control algorithms, achieving fast switching response with simple circuitry
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
This solution enables the secondary switch to be closed sooner, minimizing power wastage and preventing short circuits, thereby improving efficiency in high-power switch converter operations.
Implementation Method 1
The high-pass filter is configured to filter out a switching transient edge in the feedback signal that is generated in response to the primary switch being open
Data Source
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Figure 1B
Figure 1C
AI summary
Embodiments of a switch converter are disclosed. The switch converter includes switching circuitry with a primary and a secondary switch, an output filter, a high-pass filter, switch control circuitry, and a trigger circuit. The output filter is connected to the switching circuitry. The switch control circuitry controls operation of the primary switch and the secondary switch so that the output filter generates a DC voltage and an enabling signal. The high-pass filter receives a feedback signal and detects a switching event of the switching circuitry with the feedback signal that is generated during a dead time of both the primary switch and the secondary switch are open simultaneously. The transient detector circuit generates a trigger signal in response to the switching event and an enabling signal being in an enabling state. The switching circuitry closes the secondary switch in response to the trigger signal.