Sense IGBT Gate Voltage Control for Stable Overcurrent Detection
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Solution Overview
Problem
Conventional semiconductor devices experience oscillations in the sense current detection signal during transient periods, leading to potential malfunctions or device breakdowns due to high voltage oscillations, which deteriorate the reliability of the device operation.
Innovation Solution
Incorporation of a voltage control circuit with bidirectional diodes and capacitors to manage the gate voltage of current monitoring elements, reducing the impact of self-charging and oscillations in the sense current detection signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional IPS configuration with sense IGBT is used to monitor current, then current monitoring function is achieved, but oscillation occurs in the sense current detection signal during transient periods causing potential malfunction or device failure
Solution Approach 1:
A voltage control circuit is introduced as an intermediary between the gate voltage source and the sense IGBT gate. This circuit includes a first diode for charging the gate voltage and a second diode for discharging the gate voltage, along with associated capacitors. The voltage control circuit acts as a mediator that filters and stabilizes the gate voltage applied to the sense IGBT, preventing oscillations in the sense current detection signal while maintaining reliable current monitoring functionality.
2Reliability
If bidirectional diodes and capacitors are added to control gate voltage, then oscillations are reduced and reliability is improved, but device complexity increases
Solution Approach 1:
The voltage control circuit changes the electrical parameters (voltage levels, charging/discharging rates) applied to the sense IGBT gate through diode-based voltage regulation. By controlling the gate voltage parameters with first and second diodes in specific configurations, the circuit achieves oscillation suppression without requiring complex active control components, thereby improving reliability while limiting complexity growth.
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 proposed solution effectively reduces oscillations in the sense current detection signal, preventing malfunctions and ensuring accurate overcurrent detection and protection in semiconductor devices.
Implementation Method 1
a first diode configured to charge a gate voltage applied to a gate of the current monitoring element
Implementation Method 2
a second diode configured to discharge the gate voltage
Implementation Method 3
a voltage control circuit that includes a first diode configured to charge a gate voltage applied to a gate of the current monitoring element and a second diode configured to discharge the gate voltage
Data Source
AI summary
A semiconductor device includes an output element configured to switch on and off based on a drive signal, so as to drive a load, a current monitoring element configured to monitor a current that flows through the output element, and a voltage control circuit that includes a first diode configured to charge a gate voltage applied to a gate of the current monitoring element and a second diode configured to discharge the gate voltage, so that the voltage control circuit controls the gate voltage. An anode of the first diode is connected to a gate of the output element and a cathode of the second diode, and a cathode of the first diode is connected to an anode of the second diode and the gate of the current monitoring element.