Boost Converter Discharging Loop for Over-Current Protection
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Solution Overview
Problem
Boost converters face issues with over-current and potential drift due to parasitic diode conduction, leading to potential damage during short-circuit conditions and transitions from heavy to light loads, as existing protection mechanisms fail to effectively manage energy release.
Innovation Solution
A boost converter design incorporating a discharging loop in parallel with the inductor, a PWM circuit, and a logic circuit to detect and manage energy release via a third switch unit when discharging values exceed thresholds, utilizing an auxiliary loop for transient energy discharge before activating the main discharging loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protection mechanism is triggered to turn off the semiconductor switch during short-circuit, then the short-circuit current is blocked, but the current still flows to the load via the parasitic diode of the semiconductor switch causing damage
Solution Approach 1:
A third semiconductor switch is introduced as an intermediary component connected in parallel with the inductor. This switch acts as a mediator to provide a controlled discharge path for the inductor current, preventing the current from flowing through the parasitic diode of the first switch unit. The third switch unit is controlled by a control circuit that detects overcurrent conditions and activates the discharge path accordingly.
2Reliability
If the protection mechanism is activated when switching from heavy load to light load, then the current flow is limited, but the remaining energy of the inductor causes overdrift at the output electric potential
Solution Approach 1:
The third semiconductor switch serves as a controlled intermediary that provides a dedicated energy dissipation path. When the load transitions from heavy to light, the control circuit detects the condition and activates the third switch unit, allowing the inductor's remaining energy to be discharged through the parallel path rather than causing output voltage overdrift. This maintains output stability while protecting the system.
Solution Approach 2:
The control circuit performs preliminary detection of load conditions and proactively activates the third switch unit before significant voltage overdrift occurs. By detecting the transition from heavy to light load conditions in advance, the system prepares the discharge path to handle the inductor's remaining energy, preventing instability before it manifests.
3Power
If the inductor releases energy to the output end, then the power conversion function is achieved, but over-current conditions cause potential drift and component damage risk
Solution Approach 1:
The current path is segmented into two separate paths: the main power conversion path through the first and second switch units, and a parallel discharge path through the third switch unit. This segmentation allows the system to route normal operating current through the main path while directing excess or problematic current through the controlled discharge path, preventing over-current damage and potential drift.
Solution Approach 2:
The third switch unit acts as a controlled intermediary that monitors and manages energy release from the inductor. By detecting over-current conditions and activating the parallel discharge path, it mediates between the inductor's energy release requirement and the system's protection requirement, allowing safe energy dissipation without causing harmful effects.
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 design effectively reduces the risk of output capacitance damage by managing over-current and potential drift, ensuring safe energy release and minimizing the risk of component damage.
Implementation Method 1
the inductor selectively stores energy by controlling the power input end or releases energy to the output end according to the turn-on or turn-off of the first switch unit and the second switch unit
Implementation Method 2
When the discharging value exceeds a threshold value, the third switch unit is turned on, and the inductor releases energy via the discharging loop
Data Source
AI summary
A boost converter and a power control method thereof. The boost converter includes an inductor, a first switch unit, a second switch unit, a discharging loop and a detecting circuit. The inductor is electrically connected to a power input end. The first switch unit is electrically connected between the inductor and ground. The second switch unit is electrically connected between the inductor and an output end. The discharging loop is connected with the inductor in parallel and includes a third switch unit. The detecting circuit is used to detect a discharging value of the inductor. When the discharging value exceeds a threshold value, the third switch unit is turned on, and the inductor releases energy via the discharging loop.