Serial Data Link Power-Down Detection via Illegal Differential State
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Solution Overview
Problem
High-speed serial data links in mobile devices consume significant power, necessitating a solution that optimizes power consumption while maintaining effective communication.
Innovation Solution
A serial data link using differential signals with a transmitter that enters a power-down state, automatically detected by the receiver, eliminating the need for additional control logic and circuitry to convey power-down conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a serial data link maintains continuous operation to ensure reliable communication, then communication reliability is improved, but power consumption increases
Solution Approach 1:
The transmitter circuit is designed to dynamically switch between active and power-down states based on communication needs. The circuit can enter a power-down state to conserve energy while maintaining the capability to quickly resume transmission when needed, thus balancing power consumption with communication reliability.
Solution Approach 2:
A detect circuit monitors the differential output signals to determine whether the transmitter is in an active or power-down state. This feedback mechanism allows the receiver to automatically adapt to the transmitter's state without requiring additional control signaling, enabling power savings while maintaining reliable communication through automatic state detection.
2Reliability
If additional control circuitry is added to signal power-down states, then power-down control reliability is improved, but device complexity increases
Solution Approach 1:
The transmitter's differential output signals serve dual purposes: they carry data information during active transmission and simultaneously indicate the power-down state when both outputs are at zero voltage. This self-service approach eliminates the need for separate control signaling circuits, as the existing data signals automatically convey the transmitter's operational state to the receiver.
Solution Approach 2:
The differential output signals perform multiple functions: they transmit data during active operation and indicate power-down status when both signals are at zero voltage. This multi-functionality allows a single signal path to handle both data communication and control signaling, reducing overall circuit complexity while maintaining reliable power-down control.
Data Source
AI summary
A serial data link (10) includes a transmitter (12) using a differential transmitter cell (20) to transmit data using differential signals and a receiver (14) using a differential receiver cell (22) to receive differential signals. When the transmitter (12) is in a power-down state, the differential signals from the differential transmitter cell (20) are set to an illegal state that is detected by the receiver cell (22). Upon detecting the illegal state, unnecessary circuitry in the receiver (14) is shut off or placed in a low power state to conserve energy. When data transmission resumes, the receiver cell (22) automatically restores power to its circuitry and resumes receiving data.