Memory Interface Signal Toggling to Balance Transistor Aging
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Solution Overview
Problem
In multichip integrated circuit packages, the differential clock signal causes NMOS transistors to degrade due to hot carrier injection, while the low activity of command/address signals leads to negative bias temperature instability in PMOS transistors, resulting in reduced timing margins due to uneven transistor aging.
Innovation Solution
Periodically toggling the row and column control signals during idle periods to match the aging rate of clock signal transistors, ensuring that both types of transistors age at a comparable rate, thus maintaining timing margins without the need for interface recalibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the clock signal is driven by NMOS transistors continuously, then the clock signal can toggle indefinitely providing stable timing, but the NMOS transistors degrade due to hot carrier injection reducing timing margins
Solution Approach 1:
The patent applies periodic action by toggling command/address signals during idle periods instead of maintaining them in a static state. This periodic switching activity causes PMOS transistors to age at a rate comparable to NMOS transistors, balancing the aging effects and preventing excessive degradation from continuous static operation.
Solution Approach 2:
The patent changes the operational parameters of command/address signals during idle periods by forcing them to toggle between logic states. This parameter change transforms the static signal condition into a dynamic switching condition, altering the aging characteristics of PMOS transistors to match NMOS aging rates.
2Use of energy by moving object
If command/address signals are held static during idle periods, then power consumption is reduced, but PMOS transistors degrade due to negative bias temperature instability reducing timing margins
Solution Approach 1:
The patent applies periodic action by toggling command/address signals during idle periods instead of maintaining them in a static state. This periodic switching activity causes PMOS transistors to age at a rate comparable to NMOS transistors, balancing the aging effects and preventing excessive degradation from continuous static operation.
Solution Approach 2:
The patent converts the harmful effect of PMOS transistor degradation from static operation into a beneficial balancing mechanism. By intentionally introducing switching activity during idle periods, the patent causes controlled aging that equalizes the degradation rates of NMOS and PMOS transistors, ultimately preserving timing margins.
3Stability of the object's composition
If NMOS and PMOS transistors age at different rates, then device functionality is maintained, but timing margins are substantially reduced due to uneven aging
Solution Approach 1:
The patent applies periodic action by toggling command/address signals during idle periods instead of maintaining them in a static state. This periodic switching activity causes PMOS transistors to age at a rate comparable to NMOS transistors, balancing the aging effects and preventing excessive degradation from continuous static operation.
Solution Approach 2:
The patent changes the operational parameters of command/address signals during idle periods by forcing them to toggle between logic states. This parameter change transforms the static signal condition into a dynamic switching condition, altering the aging characteristics of PMOS transistors to match NMOS aging rates.
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 approach effectively mitigates transistor aging effects, maintaining timing margins and preventing downtime in high-performance applications by ensuring that all transistors age at a similar rate, thereby maintaining interface performance without recalibration.
Implementation Method 1
The high activity factor of the clock signal degrades the n-channel metal-oxide-semiconductor (NMOS) transistors in the clock driver due to the hot carrier injection (HCI) phenomenon.
Implementation Method 2
the low activity factor of the command/address signals with the p-channel metal-oxide-semiconductor (PMOS) transistors in the command/address signal drivers driving those signals high will cause the PMOS transistors in the drivers to degrade due to the negative bias temperature instability (NBTI) phenomenon.
Data Source
AI summary
An integrated circuit is operable to communicate with an external component. The integrated circuit may include driver circuits for outputting clock signals and associated control signals to the external component in accordance with a predetermined interface protocol. The clock signals may toggle more frequently than the associated control signals. To help mitigate potential transistor aging effects that could negatively impact timing margins for the control signals, the control signals may be periodically toggled even during idle periods as allowed by the predetermined interface protocol to help improve timing margins.