Graphics Memory Termination Switching for Power and Heat Reduction

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Solution Overview

Problem

High-speed memory technologies like GDDR3 incur increased on-chip power dissipation and heat due to on-die termination, making them undesirable for applications with power or thermal budgets, such as notebook computers, despite offering improved signal quality and higher memory clock rates.

Innovation Solution

A graphics system with adjustable on-die memory termination, allowing selection of termination impedance and switching threshold based on operating mode, switching to a power savings mode with reduced clock rate and operating un-terminated to minimize DC leakage current, thereby achieving power savings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If on-die termination is used in GDDR3 memory to improve signal quality and increase memory clock rates, then signal quality and speed are improved, but on-chip power dissipation increases

Engineering Contradiction:

Improvememory clock rateVSAvoidon-chip power dissipation

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic switching of termination impedance values based on operating conditions. The termination circuit can switch between different impedance states (e.g., 50 ohms, 75 ohms, or high impedance) depending on the memory clock rate and power requirements, allowing the system to optimize between signal quality and power consumption in real-time

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the termination impedance parameter dynamically based on operating mode. By adjusting the termination impedance value according to the memory clock rate and power budget constraints, the system can achieve high-speed operation when needed while reducing power dissipation during lower-performance periods

Inventive Principle:

Principle #35Parameter changes

2Productivity

If higher memory clock rates are used to improve performance, then speed is improved, but power consumption and heat dissipation increase

Engineering Contradiction:

Improvememory performanceVSAvoidheat dissipation

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The system dynamically adjusts the termination circuit impedance based on the current memory clock rate and thermal conditions. When operating at higher clock rates for improved performance, the termination is optimized for signal quality. When performance requirements are lower, the system can switch to a high-impedance state to minimize power consumption and heat generation

Inventive Principle:

Principle #15Dynamics

3Speed

If on-die termination is implemented to achieve higher memory clock rates, then memory speed increases, but DC leakage current increases

Engineering Contradiction:

Improvememory clock rateVSAvoidDC leakage current

Core Design Contradiction:

SpeedVSQuantity of substance

Solution Approach 1:

The termination circuit is designed to dynamically switch between low-impedance and high-impedance states. During high-speed operation, the low-impedance termination is activated to ensure signal integrity. During idle or low-performance periods, the circuit switches to a high-impedance state that dramatically reduces DC leakage current while maintaining the capability to quickly return to low-impedance mode when high speed is needed

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS7864183B1Dynamic switching of memory termination characteristics in a graphics system

Publication Date: 2011.01.04 NVIDIA CORP

AI summary

A graphics system includes a graphics memory. The graphics system includes a high performance mode and at least one power savings mode. A termination impedance and switching threshold of the graphics memory are selected based on an operating mode of the graphics system.