Gate Driver Circuit with Adjustable Transistor for Negative Bias
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Solution Overview
Problem
Conventional gate driving circuits face challenges in adjusting the constants of circuit elements in accordance with the main switching element, particularly due to the inclusion of diodes that complicate the adjustment of capacitor and diode constants.
Innovation Solution
The proposed gate driving device includes a gate driver circuit with specific transistors and logic control, along with external capacitors and diodes, allowing for adjustable constants and negative bias application tailored to the transistor being driven.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diode is used as switching means in the gate driving circuit, then the circuit can generate negative bias for high-speed turn-off, but it becomes difficult to adjust the constants of the capacitor and diodes to match the main switching element
Solution Approach 1:
The patent replaces the fixed diode with a transistor whose on-resistance can be adjusted by changing its width-length ratio. This allows the circuit parameters to be modified to match different main switching elements, resolving the contradiction between maintaining reliable turn-off behavior and enabling adjustability of circuit constants.
Solution Approach 2:
The transistor serves multiple functions: it acts as a switch, a current source for charging the capacitor, and its on-resistance can be adjusted to match different load requirements. This multi-functionality eliminates the need for separate diode components and enables universal application across different transistor types.
2Ease of manufacture
If the gate driving circuit uses fixed circuit elements, then the circuit design is simplified, but the constants cannot be adjusted to match different transistors
Solution Approach 1:
The patent introduces dynamic adjustability by making the transistor's on-resistance variable through geometric parameter changes (width-length ratio). This allows the circuit to adapt to different transistor characteristics while maintaining a relatively simple overall structure, balancing ease of manufacture with adaptability.
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
This configuration enables flexible adjustment of circuit elements and negative bias levels, improving the turn-off behavior and reducing switching losses of the transistor.
Implementation Method 1
a first capacitor provided outside... the capacitance node being connected to one electrode of the first capacitor... electric charge stored in the capacitor is used to charge or discharge the gate capacitance
Implementation Method 2
The first diode has an anode connected to the second node and to the other electrode of the first capacitor
Data Source
AI summary
A gate driving device according to the present disclosure includes a gate driver circuit, a first capacitor provided outside, and a first diode. The gate driver circuit includes first and second transistors that operate complementarily, are connected in series between a first node at a first voltage and a second node at a second voltage lower than the first voltage, and have a connection node serving as an output node of the gate driving device; a first charge transistor and a first negative-bias transistor that are connected in series between the first node and a third node at a third voltage lower than the first voltage and higher than the second voltage and have a connection node connected to one electrode of the first capacitor; and a logic circuit that controls each transistor.