Gate Drive Discharge Circuit for Indeterminate Voltage Protection
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Solution Overview
Problem
Semiconductor devices face malfunctions due to unintended switching of switching elements when the voltage at the gate terminal becomes indeterminate, leading to potential damage and prolonged malfunction.
Innovation Solution
A semiconductor device configuration that includes a boost circuit, switching elements, and resistors with specific resistance values to quickly switch the switching element to the OFF state by forming a path with lower resistance, thereby reducing the indeterminate voltage period and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the voltage at the gate terminal becomes indeterminate, then the switching element may unintentionally switch on, but this causes malfunction and potential damage to the semiconductor device
Solution Approach 1:
The patent applies preliminary anti-action by proactively preventing the harmful effect of indeterminate voltage before it can cause malfunction. The control circuit is designed to detect when the voltage at the gate terminal becomes indeterminate and immediately responds by switching the switching element to the OFF state, thereby counteracting the potential harmful effect before it can manifest as device malfunction or damage.
Solution Approach 2:
The patent converts the harmful indeterminate voltage condition into a beneficial trigger for protection. Instead of allowing the indeterminate voltage to cause random switching and potential damage, the system uses the detection of this condition as a signal to activate the protective switching action, transforming a potentially harmful situation into a controlled protective response that enhances device reliability.
2Loss of time
If a path with lower resistance is formed to quickly switch the switching element to the OFF state, then the duration of indeterminate voltage is reduced, but this requires specific resistor configurations and circuit complexity
Solution Approach 1:
The patent applies segmentation by dividing the protection function into distinct circuit components with specific roles. The control circuit is segmented into a detection unit that monitors gate terminal voltage conditions and a switching control unit that executes the OFF state transition. Additionally, the resistor network is segmented into specific configurations (including resistors with different resistance values connected to gate and source terminals) that work together to create the low-resistance discharge path, allowing the protection function to be achieved through coordinated modular components.
Solution Approach 2:
The patent uses intermediary elements to bridge the detection and response functions. The control circuit acts as an intermediary between the indeterminate voltage condition and the switching element, translating the voltage condition into a controlled switching action. Specific resistors serve as intermediaries to create the discharge path, with their values carefully selected to balance the need for quick switching against the requirement to maintain normal boost circuit operation during regular functioning.
3Reliability
If the first switching element is switched to on state after the second switching element, then the switching sequence is controlled, but this requires precise timing control
Solution Approach 1:
The patent implements feedback by using the control circuit to continuously monitor the voltage conditions at the gate terminal and adjust the switching sequence accordingly. The control circuit detects when the voltage becomes indeterminate and uses this feedback information to trigger the appropriate switching sequence, ensuring that the first switching element is activated after the second switching element in the correct temporal order. This feedback mechanism allows precise timing control without requiring complex external timing circuits.
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 suppresses malfunctions by rapidly switching the switching element to the OFF state, reducing the duration of indeterminate voltage and preventing damage, while maintaining boost performance in normal conditions.
Implementation Method 1
a first switching element, a first resistor, and a second resistor that are coupled in parallel between the gate terminal and a source terminal
Implementation Method 2
a boost circuit configured to apply a first voltage to a gate terminal
Data Source
AI summary
According to one embodiment, a semiconductor device includes: a boost circuit configured to apply a first voltage to a gate terminal; a first switching element, a first resistor, and a second resistor that are coupled in parallel between the gate terminal and a source terminal; a second switching element coupled in series with the second resistor between the gate terminal and the source terminal; a switching element control circuit configured to switch, in response to a change of a voltage from the first voltage applied from the boost circuit to the gate terminal to being indeterminate, the first switching element to on state after switching the second switching element to on state. A resistance value of the second resistor is smaller than a resistance value of the first resistor.