Transistor Protection Circuit Using Freewheeling Diode Voltage Check
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Solution Overview
Problem
Existing technologies fail to prevent simultaneous conductive states of series-connected transistors, which can lead to short circuits and undefined behavior due to internal capacitances and freewheeling diodes switching unintentionally.
Innovation Solution
A method and device that check the state of the freewheeling diode of the second transistor before switching, using a voltage measurement and evaluation circuit to ensure that transistors are only switched when the freewheeling diode is not conductive, thereby preventing simultaneous conductive states and minimizing power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If transistors are switched alternately between conducting and blocking states to generate output voltage, then power efficiency is improved, but simultaneous conductive state may occur causing short circuits
Solution Approach 1:
The invention checks the state of the freewheeling diode before switching the transistor to the conductive state. This preliminary check ensures that the transistor will not turn on simultaneously with the other transistor, preventing short circuits while maintaining efficient alternating operation.
Solution Approach 2:
The invention uses a measuring device to continuously monitor the state of the freewheeling diode and provides feedback to the switching control. Based on this feedback, the switching decision is made only when it is safe to switch, ensuring reliable operation while maintaining power efficiency.
2Device complexity
If internal capacitances of transistors are not considered, then device complexity is reduced, but unintentional activation occurs due to capacitance discharge
Solution Approach 1:
The invention performs a preliminary check of the freewheeling diode state before enabling transistor switching. This prevents the transistor from being activated by discharge currents from internal capacitances, as the check ensures the freewheeling diode is not conductive, which would indicate a unsafe switching condition.
Solution Approach 2:
The invention introduces a measuring device as an intermediary between the transistor switching control and the actual switching action. This intermediary monitors the freewheeling diode state and controls the switching timing, preventing unintentional activation while maintaining relatively simple overall device architecture.
3Productivity
If switching timing is not verified, then productivity is improved by faster switching, but undefined circuit behavior occurs
Solution Approach 1:
The invention performs a quick preliminary check of the freewheeling diode state immediately before each switching action. This maintains fast switching speed while ensuring that each switch occurs at a defined, safe moment in the operating cycle, preventing undefined circuit behavior.
Solution Approach 2:
The measuring device provides real-time feedback on the freewheeling diode state, enabling the control system to make immediate switching decisions based on actual circuit conditions. This feedback mechanism defines the switching timing precisely, ensuring reliable and predictable circuit behavior while maintaining high switching productivity.
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 approach ensures reliable operation by preventing short circuits and undefined behavior, allowing for efficient use of transistors in various applications by ensuring they are only activated at specific times, thus reducing power loss and increasing efficiency.
Implementation Method 1
the checking of the state of the freewheeling diode of the second transistor is carried out with at least two blocking transistors of a path with a voltage measurement on the freewheeling diode of the second transistor
Data Source
Figure 1~2
AI summary
The invention relates to a method and to an apparatus for protecting transistors (S1, S3; S2, S4) arranged in at least one path, wherein transistors (S1, S3; S2, S4) connected in series to which an input voltage (Ue) is applied are arranged in a path (2), and the transistors (S1, S3; S2, S4) of a path are alternately switched between a conductive state and a blocking state in order to generate an output voltage (Ua) at the center of the path. In order to prevent both transistors (S1, S3; S2, S4) of a path from triggering, the blocking state of the second transistor (S3; S4) of the path is checked before switching a transistor (S1; S2) into the conductive state, and the switching is released by way of a signal generated during the check.