Differential Pulse-Transformer Gate Drive for Common-Mode Noise
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Solution Overview
Problem
Existing gate driving circuits are ineffective in removing common mode noise from both the input and output sides, particularly when the input side and output side are insulated.
Innovation Solution
A gate drive circuit design that includes a signal conversion circuit to convert single-ended signals into differential signals, utilizing pulse transformers with neutral points set to a first ground potential, and differential amplifier circuits to differentially amplify input difference voltages, generating gate drive signals with reference to a second ground potential, thereby canceling common mode noise on both sides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pulse transformer is used for insulation, then the circuit structure is simple, but both input and output common mode noise cannot be removed simultaneously
Solution Approach 1:
The patent segments the single pulse transformer into two separate pulse transformers (first and second pulse transformers), each dedicated to handling noise on one side. This segmentation allows independent optimization of noise filtering for both input and output sides while maintaining clear functional separation, thus managing complexity through modular design.
Solution Approach 2:
The patent transitions from a single-dimensional approach (one pulse transformer handling both sides) to a two-dimensional approach by introducing separate pulse transformers for input and output sides. This dimensional expansion in the circuit architecture enables simultaneous common mode noise removal on both sides while organizing complexity in a structured, manageable way.
2Stability of the object's composition
If the neutral point of the primary winding is set to first ground potential, then the input side reference is stable, but the output side operates in floating state causing noise susceptibility
Solution Approach 1:
The patent segments the ground reference system into two independent parts: the first ground for the input side and the second ground for the output side. By using separate ground references through the two pulse transformers and their respective differential amplifier circuits, each side maintains its own stable reference potential, eliminating the floating state issue while preserving input side stability.
Solution Approach 2:
The patent introduces the second pulse transformer and second differential amplifier circuit as intermediaries that enable the output side to operate with its own reference potential (second ground) while remaining electrically insulated from the input side. This intermediary structure resolves the conflict between input side reference stability and output side noise susceptibility by providing independent reference paths.
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 circuit effectively removes common mode noise from both the input and output sides, improving noise immunity and protecting connected devices from switching element noise.
Implementation Method 1
a first pulse transformer (3) including a primary winding and a secondary winding that are electrically insulated from each other... the primary winding having both ends to which the positive signal and the negative signal of the differential signal are input respectively
Implementation Method 2
a differential amplifier circuit that is electrically connected to the input difference voltage generation circuit, the differential amplifier circuit configured to differentially amplify the pair of input difference voltages and output a pair of output difference voltages
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A gate drive circuit 100 includes: a signal conversion circuit 2 configured to convert a gate control signal 11 into a differential signal 21 including a positive signal 21A and a negative signal 21B; a first pulse transformer 3 including a primary winding and a secondary winding that have neutral points respectively, the primary winding including the neutral point set to have the potential of the first ground, the primary winding having both ends to which the positive signal 21A and the negative signal 21B are input respectively; an input difference voltage generation circuit 6 configured to generate a pair of input difference voltages 22A and 22B at both ends of a pair of resistance elements on the basis of the voltage at both ends of the secondary winding of the first pulse transformer 3; a differential amplifier circuit 7 configured to differentially amplify the pair of input difference voltages 22A and 22B and output a pair of output difference voltages 23A and 23B; and a gate drive signal generation circuit 9 configured to generate a gate drive signal 25A on the basis of the pair of output difference voltages 23A and 23B.