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VDC-M (Voltage Droop Control – Memory)

Table of Contents

  1. Definition
  2. How it Works
  3. Features
  4. Benefits
  5. Enabling Technologies
  6. Rambus Technologies

What is VDC-M (Voltage Droop Control – Memory)?

VDC-M (Voltage Droop Control for Memory) is a power integrity feature implemented in high-speed memory systems, such as DDR5 and LPDDR5, to detect and mitigate voltage droop events that can compromise data reliability. Voltage droop refers to a temporary drop in supply voltage caused by sudden changes in current demand, which can lead to timing errors, data corruption, or system instability. VDC-M ensures that memory subsystems maintain stable operation under dynamic workloads by coordinating voltage regulation and timing adjustments.

How VDC-M works

VDC-M operates by monitoring the voltage levels supplied to memory modules and detecting droop conditions in real time. When a droop is detected, the memory controller can respond by:

  • Adjusting timing margins (e.g., tRCD, tRP) to compensate for slower signal transitions
  • Triggering refresh or retry mechanisms to preserve data integrity
  • Communicating with the power delivery network (PDN) to stabilize voltage levels

This functionality is especially critical in DDR5 systems, where higher data rates and tighter timing margins increase sensitivity to power fluctuations.

What are the key features of VDC-M?

  • Real-time voltage monitoring and droop detection
  • Integration with memory controller timing logic
  • Support for dynamic timing adjustment and error mitigation
  • Compatible with DDR5 and LPDDR5 memory standards
  • Works alongside ECC and parity protection for comprehensive data integrity
 

What are the benefits of VDC-M?

  • Improved Reliability: Prevents data corruption due to voltage instability
  • Enhanced Performance: Maintains high-speed operation even under dynamic power conditions
  • System Resilience: Supports robust error handling and recovery mechanisms
  • Power Efficiency: Enables aggressive power-saving modes without compromising stability
 

Enabling Technologies

VDC-M is enabled by:

  • Advanced memory controllers with voltage-aware timing logic
  • Power delivery networks (PDNs) with fast response regulators
  • DDR5/LPDDR5 memory modules with onboard voltage sensors
  • System firmware that configures and tunes VDC-M parameters
  • Error correction technologies like ECC and CRC
 

Rambus Technologies

Rambus offers VESA® Display Stream Compression (DSC) and VDC-M encoder and decoder IP cores that deliver visually lossless video compression performance, enabling designers to handle the growing bandwidth requirements of cutting-edge displays with higher resolutions, faster refresh rates, and greater pixel depths. Learn more here.

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