UFS Host Queue-Based Gear Shifting Power Reduction
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Solution Overview
Problem
Conventional UFS systems experience significant power consumption due to frequent gear shifting when accessing embedded and external UFS devices, especially when data transfer speed requirements are random, leading to inefficient power management.
Innovation Solution
Implementing a host with multiple queues corresponding to different communication modes and a request controller that determines the optimal queue based on request priority and number, reducing the frequency of gear shifting by servicing requests within the same speed category and preventing service starvation through selective queue management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the host controller shifts gears frequently to meet random data transfer speed requirements, then the adaptability to different transfer speeds is improved, but the power consumption increases significantly
Solution Approach 1:
The patent segments the communication interface into multiple independent lanes (Lane 0, Lane 1, etc.), each capable of operating at different gear levels simultaneously. This allows the host controller to selectively activate only the necessary number of lanes and gear levels based on current data transfer requirements, rather than frequently shifting all lanes between different gear states. The segmentation enables fine-grained control over power consumption while maintaining adaptability to varying transfer speeds.
Solution Approach 2:
The patent implements dynamic lane allocation where the host controller can independently configure each lane's gear level and activation state based on real-time traffic demands. Instead of statically assigning all lanes to a single gear level or frequently shifting all lanes together, the system dynamically adjusts each lane's operational parameters, allowing some lanes to remain active at higher speeds while others stay inactive or operate at lower speeds, thereby reducing overall power consumption while maintaining transfer speed adaptability.
2Device complexity
If the host controller uses a single lane for external UFS cards, then the device complexity is reduced, but the data transfer speed and efficiency are limited
Solution Approach 1:
The patent designs the host controller with a universal interface architecture that can accommodate both embedded UFS devices (supporting multiple lanes) and external UFS cards (typically single lane) through the same M-PHY physical layer. The controller automatically detects the device type and configures the appropriate number of lanes and gear levels, providing multi-functionality without requiring separate dedicated interfaces for different device types. This universal approach maintains simplicity while enabling high-speed transfers when external cards are used.
Solution Approach 2:
The patent extends the single lane interface to support multiple lanes by adding spatial dimensionality to the external UFS card interface. While traditional single-lane interfaces operate in one dimension (one communication path), the patent enables external UFS cards to utilize multiple lanes simultaneously, effectively transitioning from one-dimensional to multi-dimensional data transfer. This allows external cards to achieve higher transfer speeds comparable to embedded devices without fundamentally changing the interface connection method.
Data Source
AI summary
In a conventional system with a UFS storage device connected to a UFS host over one or more lanes, the lanes can support different transmission speeds, referred to as gears. The UFS host shifts lanes and gears based on the type of request it receives. When the requests arrive in random order of gear requirements, the frequent shifting of the lanes and gears causes significant power consumption. To address this issue, it is proposed to implement a queue-based shifting in which arriving requests may be queued based on their gear requirements. When a queue is selected, multiple requests in the selected queue, which are all of same or similar gear requirement, can be served. This can reduce the frequency of gear shifting, and hence reduce power consumption.