Insulated Gate Driver Current Correction for Wiring Voltage Drop
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Solution Overview
Problem
Conventional insulated gate device drive circuits face reduced drive capability due to voltage drops in wiring resistances, particularly in totem-pole output circuits, which affect the charging and discharging currents, leading to insufficient power device driving performance.
Innovation Solution
Incorporation of a charging current correction circuit using a differential amplifier and an adder circuit to amplify the potential difference across the high-side wiring resistance, and a discharged current correction circuit with comparators and bypass transistors to mitigate voltage drops and maintain current levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the power device is driven away from the power supply or ground terminals to improve layout flexibility, then the ease of manufacture and layout flexibility are improved, but the wiring resistance increases causing voltage drops that reduce the drive capability
Solution Approach 1:
The patent implements feedback by detecting the actual voltage at the power device gate terminal and comparing it with the expected voltage level. The detected voltage information is fed back to the drive circuit, which then adjusts its output to compensate for voltage drops caused by wiring resistance. This closed-loop feedback mechanism ensures that the power device receives the correct drive voltage regardless of the distance from power supply terminals, thus maintaining drive capability while allowing flexible layout.
Solution Approach 2:
The patent changes the operating parameters of the drive circuit based on detected voltage conditions. When voltage drops are detected due to wiring resistance, the drive circuit dynamically adjusts its output voltage and current parameters to compensate. This parameter adjustment allows the system to maintain proper drive capability even when the power device is positioned far from power supply terminals, enabling flexible layout without sacrificing performance.
2Reliability
If the wiring resistance is reduced to maintain drive capability, then the drive capability is improved, but the layout flexibility and ease of manufacture are reduced
Solution Approach 1:
The feedback mechanism continuously monitors the actual voltage delivered to the power device and compares it with the target voltage. When voltage drops are detected due to wiring resistance, the system automatically adjusts the drive output to compensate. This eliminates the need to minimize wiring resistance through constrained layout, as the system actively compensates for any resistance encountered, thereby maintaining both drive capability and layout flexibility.
Solution Approach 2:
The patent introduces an intermediary voltage detection and correction mechanism between the drive circuit and the power device. This intermediary system measures the actual voltage conditions and mediates the relationship between the drive circuit output and the power device input, compensating for wiring resistance effects. This intermediary approach allows flexible layout with higher wiring resistance while maintaining proper drive capability.
3Speed
If the charging current is increased to improve power device turn-on speed, then the switching speed is improved, but the voltage drop across wiring resistance increases further reducing effective current
Solution Approach 1:
The feedback system detects the actual voltage and current conditions at the power device terminal and uses this information to adjust the charging current output. When high charging current is needed for fast switching but wiring resistance causes voltage drops, the feedback mechanism signals the drive circuit to increase its output accordingly. This ensures that the effective charging current at the power device terminal remains sufficient for fast switching, despite voltage drops in the wiring.
Solution Approach 2:
The system takes preliminary anti-action by preemptively increasing the drive output current when voltage drops are anticipated or detected. Before the voltage drop can significantly reduce the effective charging current, the drive circuit has already compensated by increasing its output. This preliminary compensation ensures that the power device receives the required charging current for fast turn-on, counteracting the harmful effect of wiring resistance before it can degrade switching performance.
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 corrects the reduction in charging and discharging currents caused by wiring resistance voltage drops, ensuring the drive capability of insulated gate devices is maintained, even when the power device is driven away from the power supply or ground terminals.
Implementation Method 1
amplify the potential difference across the high-side wiring resistance
Implementation Method 2
comparators and bypass transistors to mitigate voltage drops and maintain current levels
Data Source
AI summary
An insulated gate device drive apparatus for driving an insulated gate device by using a charging current outputted from a totem-pole output circuit constituted by a high-side output transistor and a low-side output transistor. The insulated gate device drive apparatus includes a charging current correction circuit configured to perform correction to increase the charging current that is decreased by an increased voltage drop of high-side wiring resistance between a power supply and the high-side output transistor.