Browse Prior Art Database

LAN POWER MANAGEMENT Disclosure Number: IPCOM000012999D
Original Publication Date: 1999-Dec-01
Included in the Prior Art Database: 2003-Jun-12
Document File: 2 page(s) / 30K

Publishing Venue


Related People

Kazuo 2 Fujii: AUTHOR [+2]


Disclosed is a circuit which enable a lower power consumption design in Network Interface Card (NIC).

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   Disclosed is a circuit which enable a lower power consumption
design in Network Interface Card (NIC).

  It becomes very common that Notebook PC to have NIC included in
it, now a days. It becomes more important that NIC to have more
advanced power management feature, especially to achieve lower
power consumption while the system is in suspend mode. The figure
shows a block diagram of the NIC and an idea of this disclosure.
The NIC is consist of tree main blocks, LAN Controller, PHY and
Magnetic. The PHY is consist of two part, a DRIVER, which drive the
LAN transmit signal and a RECEIVER, drive the LAN Receive signal.
This PHY consumes about 300mW of power and to lower the total
system power consumption, it is very important to turn this PHY
when it is not being used, that means if the NIC is not connected
to a Network.

However, here is a contradiction,, the PHY need to be powered on
to detect the NIC is connected to a Network, it result in
consuming much power. Once PHY is powered off, the NIC can not
receive a link packet and it can not detect if it is connected to
a Network. :P. The figure shows an idea of this disclosure. A
mechanical switch to be placed at the RJ45 Jack and the switch
makes(ON) when a LAN cable is connected to the Jack. The ON/OFF
signal, the signal name is "RJ45IN#" in the figure, of the switch
is connected to PHY or LAN controller. In case a LAN cable is not
connected to the RJ45 jack, the "Shutdowm_LAN" signal becomes
high. When a PHY chip det...