Peripheral Power Gating with Context Retention in Low-Power Hosts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional power management techniques fail to achieve efficient power savings in peripheral devices connected to host devices, as they are required to remain powered on and draw substantial power even when not in use, especially in low power modes.
Innovation Solution
An intermediate device is used to manage power modes of peripheral devices independently of the host device, storing context data and power gating the peripheral device while the host is in a reduced power mode, using a programmable logic device (PLD) to reduce overall power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the peripheral device remains powered on to maintain volatile memory state, then the operational context is preserved, but substantial power is drawn even when not in use
Solution Approach 1:
An intermediate device is introduced between the host device and peripheral device. This intermediary captures context data from the peripheral device before power gating, stores it temporarily, and restores it after power gating. This mediator enables the peripheral device to be fully powered off while preserving operational state through data capture and restoration, resolving the contradiction between maintaining reliability and reducing power consumption.
Solution Approach 2:
The intermediate device performs preliminary action by capturing context data from the peripheral device's volatile memory before the peripheral device is power gated. This advance data capture ensures that when the peripheral device is fully powered off, its operational state is already preserved in the intermediate device, eliminating the need to keep the peripheral device powered on and thereby reducing power consumption while maintaining reliability.
2Use of energy by moving object
If the peripheral device transitions to reduced power mode with the host device, then power savings are achieved, but the device cannot be fully power gated due to interface requirements
Solution Approach 1:
The intermediate device serves as a mediator that decouples the interface requirements from the peripheral device's power state. It maintains the interface connection and handles data transfer while allowing the peripheral device to be fully power gated. This intermediary absorbs the interface complexity, enabling maximum power savings for the peripheral device without being constrained by interface requirements.
Solution Approach 2:
The system is segmented into three independent components: the host device, the intermediate device, and the peripheral device. This segmentation allows each component to operate independently at its optimal power state. The peripheral device can be fully powered off while the intermediate device maintains the interface connection, separating the interface maintenance function from the peripheral device and enabling complete power gating.
3Use of energy by moving object
If the peripheral device is fully powered off, then maximum power savings are achieved, but the volatile memory state is lost
Solution Approach 1:
The intermediate device acts as an intermediary that captures context data from the peripheral device's volatile memory before power gating occurs. It stores this data temporarily and restores it after the peripheral device is powered back on. This intermediary function prevents information loss while enabling the peripheral device to be fully powered off, achieving maximum power savings without sacrificing data retention.
Solution Approach 2:
The intermediate device creates a copy of the context data from the peripheral device's volatile memory before power gating. This copy is stored in the intermediate device's memory, allowing the original volatile memory to be cleared when the peripheral device is powered off. When needed, the copy is restored to the peripheral device, preventing information loss while enabling complete power shutdown.
Data Source
AI summary
Various techniques are provided for managing power modes (e.g., also referred to as power states) in peripheral devices connected to host devices. In one example, a method includes receiving, by an intermediate device communicatively connected between a host device and a peripheral device, a notification that the host device will transition from a high power mode to a reduced power mode. The method also includes receiving, by the intermediate device from the peripheral device, context data associated with an operational state of the peripheral device. The method also includes storing, by the intermediate device, the context data, and power gating the peripheral device by the intermediate device while the host device remains at least partially turned on in the reduced power mode. Additional embodiments are provided to restore the operational state of the peripheral device using the stored context data. Additional systems, devices, and methods are also provided.