System and method for standby power reduction in a serial communication system
View Patent ↗In a serial communication system having a device including a receiver detection module, this specification is directed to systems and methods for selectively reducing the power consumed by the receiver detection module, preferably when the device is operating in a low power mode. In some embodiments, a signal detection module is configured to receive a control signal from the transmitter of a device at the other end of the communications link to control the operation of the receiver detection module. The control signal may be in-band or may be transmitted on a sideband of the serial link.
1. A communication system comprising:
a transmitter;
a receiver including a receiver detection module and a power module; and
a serial link between the transmitter and the receiver,
wherein the receiver detection module to be operable during a power save state of the serial link to determine an operational condition of the serial link and wherein the power module to selectively operate the receiver detection module in a low power mode during the power save state of the serial link by transitioning the receiver detection module from the low power mode to an active mode in response to a control signal sent by the transmitter during the power save state of the serial link,
a sideband link between the transmitter and the receiver, wherein the power module to selectively operate the receiver detection module in the low power mode on the basis of the control signal carried by the sideband link.
2. The communications system of claim 1 , wherein the low power mode of the receiver detection module is a duty cycle mode.
3. The communication system of claim 1 , wherein the serial link comprises a PCIe link.
4. The communication system of claim 1 , wherein the receiver detection module comprises electric idle detection logic.
5. The communication system of claim 4 , wherein the power module to disable the electric idle detection logic to selectively operate the receiver detection module in the low power mode.
6. A serial communication system comprising a host having a transmitter and a client having a receiver, wherein the transmitter and the receiver to communicate through transfer of differential data signals over a link using a protocol that specifies at least one active state and at least one power save state, a receiver detection module in the client to be operable during the power save state to determine an operational state of the link, and a power module in the client to selectively operate the receiver detection module in a low power mode on the basis of a control signal from the host by transitioning the receiver detection module from the low power mode to an active mode in response to the control signal sent during the power save state of the serial link,
wherein the serial communication system is a PCIe system and wherein the active state of the serial communication system is a L0 link state and the power save state of the serial communication system is a L 1 link state;
a sideband and wherein the power module receives the control signal on the sideband.
7. The serial communication system of claim 6 , wherein the receiver detection module comprises electric idle detection logic and wherein the low power mode of the receiver detection module disables the electric idle detection logic.
8. The serial communication system of claim 6 , wherein the power module to selectively operate the receiver detection module in low power mode by operating the receiver detection module in a duty cycle mode.
9. A method for standby power reduction in a serial communication system having a transmitter and receiver, communicating over a serial data link, comprising:
operating the serial data link in a power save state; and
selectively operating a receiver detection module of the receiver to determine an operational condition of the serial data link in a low power mode while the serial data link is in the power save state, wherein selective operation of the receiver detection module includes transitioning the receiver detection module from the low power mode to an active mode in response to a control signal sent by the transmitter during the power save state of the serial link,
wherein determining the operational condition of the serial data link comprises determining an operational condition of a PCIe link, wherein the power save state of the serial data link is an L1 state, and wherein operating in the low power mode comprises disabling electrical idle detection logic in the receiver detection module,
coupling the transmitter and receiver with a sideband link and sending the control signal on the sideband link, wherein the control signal comprises a transition in a sideband signal.