I/O Driver Feedback Timing for Noise and Power Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The amplification of low core voltage signals to higher interface voltage signals in I/O devices results in significant noise due to increased current, causing voltage overshoot, undershoot, VDDIO droop, and ground bounce effects.
Innovation Solution
A method to reduce I/O noise by controlling the current flow in I/O drivers through PMOS and NMOS transistors using feedback loops and threshold voltage sensitive devices, which selectively reduce current after a non-zero time delay following signal changes, thereby minimizing noise and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If current flow in I/O driver is increased to achieve higher interface voltage signal, then signal amplification is improved, but noise levels increase due to voltage overshoot, undershoot, VDDIO droop and ground bounce effects
Solution Approach 1:
The patent applies preliminary action by introducing a time delay mechanism that activates current reduction after a non-zero time delay following signal change. This preliminary timing control allows the signal to establish itself before reducing current, preventing noise generation while maintaining signal integrity. The feedback loop monitors signal state and triggers current reduction at the optimal moment.
Solution Approach 2:
The patent implements feedback by using threshold voltage sensitive devices to monitor the output signal and control current flow through feedback loops. The feedback mechanism detects when the signal has stabilized and automatically reduces current flow accordingly, creating a closed-loop control system that dynamically adjusts current based on signal state to minimize noise while maintaining amplification capability.
2Object-generated harmful factors
If current flow in I/O driver is reduced to decrease noise, then noise levels are reduced, but signal amplification capability deteriorates
Solution Approach 1:
The patent applies periodic action by implementing time-periodic current control where current flow is maintained at high levels during signal transitions and then reduced periodically after a non-zero time delay. This periodic switching between high and low current states allows the system to achieve both strong signal amplification during transitions and low noise during stable periods, creating a rhythm of high-performance operation followed by low-power operation.
3Speed
If time delay for current reduction is shortened to improve response speed, then propagation delay is reduced, but noise reduction effectiveness decreases
Solution Approach 1:
The patent implements dynamics by making the current control system adaptive and dynamic rather than static. The time delay parameter can be adjusted based on operating conditions, and the feedback loop continuously monitors signal state to determine optimal current reduction timing. This dynamic approach allows the system to optimize the balance between response speed and noise reduction for different signal conditions and loading scenarios.
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 solution effectively reduces noise and power consumption by controlling current flow through the I/O drivers, achieving noise reductions of up to 47.30% with slew rate control capacitors, and improving propagation delay, overshoot, undershoot, and ground bounce performance.
Implementation Method 1
providing a first threshold voltage sensitive device to monitor the output of the I/O driver. The first threshold voltage sensitive device may be defined by a first inverter and may control the current through the NAND gate by controlling a first current control transistor connected to the NAND gate
Data Source
AI summary
In an I/O circuit, noise reduction and power savings are achieved by providing feedback from the output of the I/O driver to control the current through the pre-driver and thereby the current through the driver transistors after a non-zero time delay following a low to high or high to low data signal change.