Bus Driver Circuit With Intermediate Switching for EMI Reduction
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Solution Overview
Problem
Existing driver circuits for digital transmitting buses generate significant electromagnetic emissions during switching operations, which can be costly to mitigate using external inductors, as they require a certain inductance and size, making them unsuitable for integration and increasing costs for ECU manufacturers.
Innovation Solution
A driver circuit with a main switch that has multiple switching states, including an intermediate state with varying electrical conductivity between minimum and maximum conductivity, controlled by digital signals to reduce electromagnetic emissions without the need for external inductors, by successively increasing or decreasing conductivity during switching operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If external inductors are used to damp electromagnetic emissions, then electromagnetic emissions are reduced, but device complexity and cost increase
Solution Approach 1:
The invention extracts the electromagnetic emission damping function from external inductors and implements it within the driver circuit itself through intermediate switching states. The driver circuit generates intermediate voltage levels between minimum and maximum conductivity states, effectively damping emissions without requiring external inductor components.
Solution Approach 2:
The driver circuit serves itself by generating intermediate switching states that inherently damp electromagnetic emissions. The circuit uses its own switching mechanism to create intermediate conductivity states, eliminating the need for separate external damping components and reducing overall system complexity.
2Object-affected harmful factors
If external inductors are used to damp electromagnetic emissions, then electromagnetic emissions are reduced, but manufacturing cost increases
Solution Approach 1:
The invention removes the need for external inductor components by integrating the emission damping function into the driver circuit's switching mechanism. This eliminates the cost of purchasing and installing external inductors while maintaining effective electromagnetic emission damping.
Solution Approach 2:
The invention uses software-controlled switching states instead of expensive physical inductor components. The intermediate conductivity states are generated through control logic that transitions the switch between minimum and maximum conductivity, providing a cost-effective alternative to external inductors.
3Object-affected harmful factors
If external inductors are used to damp electromagnetic emissions, then electromagnetic emissions are reduced, but integration becomes difficult due to size
Solution Approach 1:
The invention extracts the damping function from large external inductor components and implements it within the compact driver circuit. By using intermediate switching states to generate intermediate voltage levels, the circuit achieves emission damping without requiring the physical space of external inductors.
Solution Approach 2:
The invention transitions from a spatial solution (external inductors occupying physical space) to a temporal solution (intermediate switching states over time). The intermediate conductivity states are achieved through time-based control of the switch, eliminating the need for additional physical dimensions occupied by external inductors.
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 solution effectively reduces electromagnetic emissions by smoothing the power spectrum during switching, eliminating the need for external inductors and thereby reducing costs and complexity in ECU design.
Implementation Method 1
a main switch connected to the bus, which is controllable by the digital signal to be transmitted and has one on-switching state in which it has maximum electrical conductivity, one off-switching state in which it has minimum electrical conductivity and at least one intermediate switching state with an electrical conductivity between the minimum and maximum conductivity
Data Source
AI summary
A driver circuit for a digital signal transmitting bus includes a main switch. The main switch is connected to the bus, is controllable by the digital signal to be transmitted, and has one on-switching state in which it has maximum electrical conductivity, one off-switching state in which it has minimum electrical conductivity and at least one intermediate switching state with an electrical conductivity between the minimum and maximum conductivity. The digital signal has a first logic state and a second logic state, the first logic state controls the main switch to be in the on-switching state and the second logic state controls the main switch to be in the off-switching state. The main switch is in the intermediate switching state during switching from the on-switching state to the off-switching state and/or vice versa.