Variable-Drive Interface Circuit for Low-Noise Signal Transitions
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Solution Overview
Problem
Existing electronic device interface circuits face challenges in signal transition times, leading to electro-magnetic interference (EMI), electrical over-stress (EOS), and power noise, which degrade device performance and image quality in image sensing devices, while additional noise-reducing circuits increase manufacturing costs.
Innovation Solution
The design includes a resistance element and driving elements with a controller that generates control signals using different driving powers during signal transitions, optimizing the transition period by determining initial and remaining periods based on threshold voltages, and utilizing main and sub drivers to manage voltage levels and current sources for precise signal control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If electrical signals transition quickly in the interface circuit, then signal transmission speed is improved, but electro-magnetic interference (EMI) and electrical over-stress (EOS) cause unwanted noise
Solution Approach 1:
The patent applies dynamics by making the driving power variable during the transition period. The controller dynamically adjusts the driving power from a first driving power to a second driving power based on the signal transition state, optimizing both transition speed and noise reduction at different moments of the transition process
Solution Approach 2:
The patent changes the driving power parameter during the transition period. By switching between different driving power levels (first driving power and second driving power) based on the transition timing and threshold voltage detection, the system optimizes signal transition characteristics while minimizing EMI and EOS effects
2Object-affected harmful factors
If electrical signals transition slowly in the interface circuit, then power noise is reduced, but timing margin decreases and signal capture becomes difficult
Solution Approach 1:
The patent divides the transition period into distinct phases with different driving power levels. By applying periodic control actions (switching between first and second driving powers) during the transition period, the system achieves both fast transition and noise reduction in different phases
Solution Approach 2:
The controller prepares and applies appropriate driving power levels in advance during the transition period. By detecting the transition timing and applying the first driving power initially, then switching to the second driving power, the system ensures optimal signal capture while controlling noise
3Reliability
If additional circuits are added to control EMI and timing margin, then signal transmission reliability is improved, but manufacturing cost increases
Solution Approach 1:
The controller performs multiple functions: it generates control signals, detects transition periods, determines threshold voltages, and adjusts driving power levels. By making the controller multi-functional, the patent avoids adding separate dedicated circuits for each function, thereby maintaining reliability while controlling manufacturing cost
Solution Approach 2:
The patent merges the functions of EMI control, timing margin management, and signal generation into a single controller unit. By combining these functions that could have been implemented by separate circuits, the system achieves reliable signal transmission without increasing device complexity and manufacturing cost
Data Source
AI summary
An electronic device includes a resistance element coupled between a supply terminal of a first voltage and an output terminal of an output signal, a driving element coupled between the output terminal of the output signal and a supply terminal of a second voltage, and suitable for operating based on a control signal, and a controller suitable for generating the control signal based on an input signal of the controller to the driving element. The controller drives an output terminal of the control signal with a first driving force during an initial period of a first transition period of the control signal, and drives the output terminal of the control signal with a second driving force different from the first driving force during the remaining period of the first transition period. The initial period is determined depending on a threshold voltage of the driving element.