Semiconductor Driving Device Adaptive Charging Short Circuit Detection
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Solution Overview
Problem
Conventional semiconductor driving devices face challenges in promptly detecting short circuits during the on-state of semiconductor elements, leading to delayed protective operations due to the blanking time setting, which can result in failure to immediately protect the semiconductor element when a short circuit occurs.
Innovation Solution
A driving device for semiconductor elements that includes a drive circuit, a charging circuit, and a shutting circuit, where the charging circuit rapidly charges a capacitive element after it reaches saturation voltage, enabling immediate detection of non-saturation voltages indicative of short circuits and subsequent protective actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a blanking time is set in the desat detection function to avoid erroneous detection of normal non-saturation voltage immediately after turn-on, then false detection is avoided, but the detection of actual short circuits is delayed
Solution Approach 1:
The patent applies dynamics by making the charging current adaptive rather than fixed. The charging circuit dynamically adjusts the current magnitude based on the operational state: using a first charging current during the blanking period after turn-on, and switching to a second (larger) charging current when saturation voltage is detected. This dynamic adjustment allows the system to maintain detection accuracy while reducing time loss for short circuit detection.
Solution Approach 2:
The patent changes the parameter of charging current magnitude based on operational conditions. By switching between a first charging current (during blanking time) and a second charging current (larger current, after saturation is reached), the system optimizes both detection accuracy and response time. This parameter change resolves the contradiction by allowing precise detection during normal operation while enabling rapid detection when short circuits occur.
2Device complexity
If a constant current is supplied to charge the capacitive element during the entire on-state, then the circuit is simple, but the detection response to short circuits is slow
Solution Approach 1:
The patent makes the charging current dynamic by switching between two different current magnitudes based on the saturation voltage detection state. The charging circuit uses a first constant current during the initial period and switches to a second (larger) constant current when saturation is detected, thereby improving detection speed without requiring a completely complex circuit design.
Solution Approach 2:
The patent prepares the detection system in advance by initially charging the capacitive element with a first constant current during the blanking period. This preliminary action ensures that when a short circuit occurs, the system is already in a state ready for rapid detection, reducing the overall response time while maintaining circuit simplicity.
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 allows for rapid protection of semiconductor elements at the occurrence of short circuits by quickly identifying non-saturation voltages, thereby reducing the risk of damage and ensuring timely protective operations.
Implementation Method 1
a capacitive element having one of its two terminals connected to the anode of the diode and having the other of its terminals connected to the second electrode, the charging circuit section charging the capacitive element
Data Source
AI summary
The device for driving the semiconductor element is provided with a drive circuit section, a charging circuit section and a shutting circuit section. The charging circuit section is electrically connected to an external circuit provided with a diode and a capacitive element. The semiconductor element has a first electrode, a second electrode and a control terminal. The cathode of the diode is connected to the first electrode. One of two terminals of the capacitive element is connected to the cathode of the diode, and the other terminal is connected to the second electrode. The charging circuit section enables the capacitive element to be charged at a higher rate after a timed point at which the voltage on the capacitive element becomes equal to a saturation voltage in a case where the input signal is an on-signal.