Isolated USB Repeater Suspend Mode With Periodic Channel Wake-Up
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Solution Overview
Problem
USB repeaters with galvanic isolation struggle to meet the USB 2.0 standard's suspend mode power requirement of 2.5 mA due to continuous current consumption by isolation channels using on-off keying, leading to potential device shutdown during suspend mode.
Innovation Solution
Implementing a method where isolation channels are turned off during suspend mode and periodically enabled to transmit signals, using independent timers and clocks on the host and peripheral sides to synchronize entry and exit from suspend mode without additional handshake operations, ensuring power consumption remains below 2.5 mA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If isolation channels use on-off keying to transmit data during suspend mode, then data communication is maintained, but current consumption exceeds 2.5 mA causing potential device shutdown
Solution Approach 1:
The patent applies periodic action by enabling isolation channels only during specific time windows when data transmission is required, rather than keeping them continuously enabled. The system periodically activates isolation channels to transmit suspend mode status and wake-up signals, then disables them to reduce current consumption below the 2.5 mA threshold, thereby resolving the contradiction between maintaining communication reliability and reducing energy usage.
2Use of energy by moving object
If isolation channels are disabled during suspend mode to reduce power consumption, then current consumption drops below 2.5 mA, but data transmission capability is lost
Solution Approach 1:
The patent applies dynamics by making the isolation channel state changeable between enabled and disabled based on operational requirements. The system dynamically adjusts the isolation channel state: disabled during most of suspend mode to minimize power consumption, and enabled temporarily when data transmission is needed (such as during wake-up events). This dynamic state change resolves the contradiction between power consumption and data transmission capability.
3Device complexity
If independent timers are used on host and peripheral sides to synchronize suspend mode entry, then coordination is achieved without additional handshake operations, but timing precision must be maintained across isolation barrier
Solution Approach 1:
The patent applies the intermediary principle by using the isolation channel itself as a mediator to synchronize timing between host and peripheral sides. The system leverages the existing isolation channel infrastructure to transmit timing information and coordinate suspend mode entry, eliminating the need for additional dedicated synchronization handshake operations. This approach reduces device complexity while maintaining timing precision through the intermediary isolation channel mechanism.
Data Source
AI summary
In an example, a method of operating a repeater having an isolation barrier to isolate a host side of the repeater from a peripheral side of the repeater, the repeater operable to be coupled to a universal serial bus (USB), includes causing the host side to enter into a suspend mode. The method also includes, responsive to entering the suspend mode, disabling a host isolation transceiver at the host side. The method includes periodically enabling the host isolation transceiver to transmit a data signal from the host side to the peripheral side. The method includes exiting the suspend mode. The method also includes enabling the host isolation transceiver.