Gate Current Measurement Circuit for High-Speed Load Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional load driving devices with gate current measurement circuits are unable to detect failures in the gate oxide film after shipment and fail to perform high-speed switching operations due to the presence of a gate resistor, which requires a stable gate voltage for an extended period, making them unsuitable for switching frequencies above 100 kHz.
Innovation Solution
A load driving device with a gate current measurement circuit that includes a voltage application circuit and a current measurement circuit capable of measuring gate current during both turn-on and turn-off, allowing for high-speed switching by restricting the gate voltage within a specific range and detecting gate oxide film failures through abnormal current detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gate resistor is used to measure gate current for detecting gate oxide film failures, then failure detection capability is improved, but switching speed deteriorates due to the extended stabilization period required
Solution Approach 1:
The patent introduces an intermediary circuit between the gate resistor and the gate terminal that includes a stabilization voltage generation circuit. This intermediary circuit generates a stabilization voltage that accelerates the stabilization process of the gate voltage, allowing the measurement of gate leak current to be completed within the brief switching period while still enabling failure detection. The intermediary circuit acts as a mediator that reconciles the conflicting requirements of measurement accuracy and switching speed.
2Productivity
If gate current measurement is performed during high-speed switching, then switching frequency can be increased above 100 kHz, but gate voltage stability deteriorates making incomplete switching operations
Solution Approach 1:
The patent applies preliminary action by generating the stabilization voltage before the gate voltage fully stabilizes on its own. The stabilization voltage generation circuit proactively provides the voltage needed to accelerate gate voltage stabilization, rather than waiting for the natural stabilization process to complete. This preliminary intervention ensures that gate voltage stability is maintained even during high-speed switching operations above 100 kHz where the natural stabilization period would be insufficient.
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
Enables the detection of gate oxide film failures even after shipment and supports high-speed switching operations, ensuring reliable performance in high-frequency applications by accurately measuring gate current and preventing voltage exceedance.
Implementation Method 1
a gate current measurement means configured to measure gate current flowing in the gate resistor
Implementation Method 2
an electric actuator such as a motor and a solenoid has widely been used. The electric actuator and a control device controlling the electric actuator are supplied from an in-vehicle battery with electric power
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The main purpose of the present invention is to provide a load driving device that is equipped with a gate current measurement circuit that can perform a high-speed switching operation. This load driving device drives a load by controlling ON/OFF of a switching element by applying a voltage to a gate terminal of the switching element. The load driving device comprises: the switching element; a gate driving circuit that applies a gate voltage of the switching element; and a current measurement circuit that measures the current of the gate terminal of the switching element. The gate driving circuit outputs a voltage that is restricted to be within a rated voltage range of an applied gate voltage of the switching element. The current measurement circuit measures a gate current of the switching element that flows from a power source, which has a voltage outside the rated voltage range of the applied gate voltage, via the gate driving circuit.