Power Switch Gate Drive Circuit for Voltage Jump Immunity
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Solution Overview
Problem
Existing gate drive circuits for power semiconductor switches are prone to damage due to voltage jumps, which can cause unintended conduction and damage, especially in applications without stable power supplies, due to the lack of effective anti-interference mechanisms.
Innovation Solution
A gate circuit and drive circuit design incorporating a zener diode and a charge dissipation circuit, where parasitic capacitors are used to detect voltage jumps and trigger the charge dissipation circuit to discharge excess charges, preventing gate voltage escalation and potential damage, utilizing a series of resistors and switches to control the dissipation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple drive circuit is used to charge and discharge the gate capacitor directly through positive and negative narrow pulses, then the circuit complexity and cost are reduced, but the anti-interference ability deteriorates and the power device may be damaged by voltage jumps
Solution Approach 1:
The patent introduces a charge dissipation circuit as an intermediary component between the gate capacitor and the power device. This circuit includes a discharge transistor, discharge resistor, and detection capacitor that work together to detect voltage jumps and dissipate abnormal charges, thereby protecting the power device without requiring a complete redesign of the simple drive circuit structure.
Solution Approach 2:
The patent implements preliminary protection by pre-configuring the charge dissipation circuit with detection capacitors connected to the gate. These capacitors are ready to detect voltage jumps before they cause damage, and the discharge transistor is pre-positioned to immediately dissipate abnormal charges when detected, preventing unintended conduction before it occurs.
2Reliability
If optical isolation driver or magnetic isolation driver is used to provide stable voltage source and logic processing, then the reliability is improved, but the device complexity and cost increase
Solution Approach 1:
The patent extracts only the essential protective function from complex isolation drivers. Instead of using full optical or magnetic isolation drivers with stable voltage sources and logic processing circuits, the invention extracts the charge dissipation function and implements it through a simple circuit with a discharge transistor, discharge resistor, and detection capacitor, achieving protection without the complexity of isolation drivers.
Solution Approach 2:
The patent uses inexpensive components for the charge dissipation circuit, including standard transistors, resistors, and capacitors. The detection capacitors can be considered as disposable elements that may be damaged by voltage spikes but are cheap to replace, providing economic protection against expensive power device failures.
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 enhances the anti-interference ability of the gate circuit, preventing unintended conduction and ensuring the reliability of power semiconductor switches by effectively managing voltage jumps and maintaining stable gate voltages, while maintaining a simple and cost-effective structure.
Implementation Method 1
A first parasitic capacitor is formed between a first end and the gate of the power semiconductor switch, and a second parasitic capacitor is formed between the gate and the second end of the power semiconductor switch
Implementation Method 2
When the current is greater than or equal to a preset value, the charge dissipation circuit will work, such that charges on the first parasitic capacitor and the second parasitic capacitor are discharged through the charge dissipation circuit
Data Source
AI summary
The present disclosure provides a gate circuit and a gate drive circuit for a power semiconductor switch, including: a zener diode and a charge dissipation circuit. A first end of the zener diode is connected to a first end of the charge dissipation circuit and a gate of the power semiconductor switch, a second end of the zener diode is connected to a second end of the charge dissipation circuit and a second end of the power semiconductor switch. A first parasitic capacitor is formed between a first end and the gate of the power semiconductor switch, and a second parasitic capacitor is formed between the gate and the second end of the power semiconductor switch.