Integrated Bus Interface Edge Acceleration for Slew Rate Control
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Solution Overview
Problem
Digital signals transmitted across electrical busses often experience degradation due to transmission line and parasitic capacitance effects, leading to slower rising and falling edges, which can hinder system timing requirements.
Innovation Solution
An integrated circuit with rising and falling time accelerators (RTA and FTA) that detect edges on bus terminals and actively drive the bus voltage to accelerate the slew rate of rising and falling edges, preventing simultaneous driving to avoid crossbar current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If digital signals are transmitted across electrical busses, then signal transmission between circuits is achieved, but rising and falling edges degrade leading to slower slew rates
Solution Approach 1:
The RTA and FTA circuits perform preliminary action by detecting edges before they fully degrade and actively accelerating them back to sharp transitions. The RTA detects rising edges and applies current to accelerate the rise, while the FTA detects falling edges and applies current to accelerate the fall, preventing timing violations before they occur.
Solution Approach 2:
The system implements feedback by continuously monitoring the bus voltage through detectors and automatically responding to edge degradation. The RTA detector monitors rising edges and triggers acceleration when needed, while the FTA detector monitors falling edges and triggers相应的 acceleration, creating a closed-loop system that maintains signal integrity.
2Speed
If RTA and FTA circuits actively drive bus voltage to accelerate edges, then slew rate is improved, but simultaneous driving could cause crossbar current
Solution Approach 1:
The RTA detector and FTA detector provide feedback about the current bus state and edge direction. This feedback mechanism ensures that only the appropriate circuit (RTA or FTA) is activated based on whether a rising or falling edge is detected, preventing simultaneous activation that would cause crossbar current.
Solution Approach 2:
Instead of having both RTA and FTA circuits continuously active and risk crossbar current, the system inverts the approach by using detectors to selectively activate only the needed circuit. The RTA detector activates RTA for rising edges, and the FTA detector activates FTA for falling edges, ensuring mutually exclusive operation.
Data Source
AI summary
An integrated circuit includes first and second bus terminals, a pass-gate transistor, first and rising time accelerator (RTA) control circuits, and first and second falling time accelerator (FTA) control circuits. The pass-gate transistor couples between the first and second bus terminals. The first RTA control circuit couples to the first bus terminal, detects a rising edge on the first bus terminal, and accelerates the rising edge on the first bus terminal. The first FTA control circuit couples to the first bus terminal, detects a falling edge on the first bus terminal having a slope below a threshold, and accelerates the falling edge on the first bus terminal. The second RTA and FTA control circuits function similar to the first RTA and FTA control circuits but with respect to the second bus terminal.