Method to control current imbalance between differential pairs providing a DC power feed
View Patent ↗The present invention provides a method to at least partially power an Ethernet device from a plurality of balanced network power signals received through a network connection. This involves attaching the network device to the network, wherein network signals are received and contain both power signals and/or data signals. These network signals may be passed through surge protection and power-conditioning circuitry wherein the output of these circuits may be provided to a power absorbing circuit. This power absorbing circuit may separate the communication signal and power signal from the network signal. The communication signal may be passed to a network physical layer while the power signal may be passed to a power distribution module. Additionally, because certain embodiments may provide multiple pairs of network power signals to the power absorbing circuit, the current or power associated with each power signal must be sensed and balanced. This may be done with an active control circuit. The balanced power signals may then be supplied from the power absorbing circuit to the network-attached device in order to at least partially power the network-attached device.
1. A method to at least partially power an Ethernet network device, with a plurality of power signals fed through an Ethernet network connection, comprising:
physically coupling the Ethernet network device to the Ethernet network;
receiving an Ethernet signal from the Ethernet network, wherein the Ethernet signal comprises the plurality of power signals and data signal(s);
passing the Ethernet signal to an integrated circuit (IC) wherein the IC comprises:
an Ethernet physical layer (PHY) module;
a power management module; and
a direct connection module that directly connects the Ethernet network device to the Ethernet network connection with no intervening magnetic transformer; p 1 separating with the direct connection module, the data signal from the Ethernet signal, wherein the data signal is passed to the Ethernet PHY module of the IC;
separating with the direct connection module, the plurality of power signals from the Ethernet signal;
sensing a current associated with each power signal of the plurality of power signals;
balancing the plurality of power signals with an active control circuit and based on the sensed current associated with each power signal of the plurality of power signals, wherein balancing the plurality of power signals comprises:
receiving the Ethernet rower signals;
determining an amplitude property of the Ethernet rower signal;
determining an insertion loss limit based on the amplitude property;
comparing the insertion loss control limit to a sampled common mode signal; and
balancing the plurality of rower signals according to the comparison, wherein the balanced plurality of power signal are passed to the power management module; and
at least partially powering the Ethernet network device from the plurality of balanced power signal.
2. The method of claim 1 , wherein the balancing the plurality of power signals with an active control circuit results in each sensed current not exceeding a reference current.
3. The method of claim 1 , wherein:
an RJ45 connector physically couples the Ethernet network device to the Ethernet network, and wherein the RJ45 connector couples to twisted pairs that further comprise conductors 1 and 2 ; 3 and 6 ; 4 and 5 ; and 7 and 8 ; and
a switching/rectifying circuit that receives the power signal utilizing conductors 1 , 2 , 3 , and 6 ; and conductors 4 , 5 , 7 , and 8 .
4. The method of claim 3 , wherein the balancing the plurality of power signals with an active control circuit results in each sensed current not exceeding a predetermined current associated with twisted pair.
5. The method of claim 1 , wherein each of the plurality of power signals does not exceed 57 volts.
6. The method of claim 1 , wherein the Ethernet PHY module implements 10 Mbps, 100 Mbps and 1 Gbps physical layer functions.
7. The method of claim 1 , wherein the IC further comprises an Ethernet media access controller (MAC) wherein the Ethernet PHY and Ethernet MAC implement hardware layers of an Ethernet protocol stack.
8. The method of claim 1 , wherein the Ethernet network device comprises at least one device selected from the group consisting of:
a voice over internet protocol (VoIP) telephone;
an Ethernet router;
an Ethernet switch;
a printer;
a data server;
an Ethernet enabled camera;
a wireless access point;
a playback device;
a portable computing device;
a personal data assistant;
a wireless terminal;
a graphics display; and
an audio interface.
9. The method of claim 1 , wherein the plurality of power signals is IEEE 802.3af compliant.
10. The method of claim 1 , wherein comprising supplying the power signal to the Ethernet network from a power sourcing equipment (PSE), and wherein the PSE determines whether the Ethernet network device is IEEE 802.3af compliant.
11. The method of claim 1 , wherein the direct connection module further comprises a power device controller.
12. The method of claim 1 , wherein separating with the direct connection module, the data signal from the Ethernet signal utilizes direct current (DC) blocking capacitors that couple the Ethernet PHY module to the Ethernet signal.
13. The method of claim 1 , wherein balancing the plurality of power signals with the active control circuit further comprises actively balancing currents associated within a twisted pair, wherein the twisted pairs conduct power signal(s).
14. The method of claim 1 , wherein balancing the plurality of power signals with the active control circuit further comprises:
actively controlling the current passed within a twisted pair.
15. An Ethernet network device that receives a plurality of power signals and data signals through a coupled Ethernet network, comprising:
an Ethernet network connector that physically couples the Ethernet network device to the Ethernet network, wherein the Ethernet network connector receives four twisted pairs that carry the plurality of power signals, wherein the plurality of power signals comprise a first power signal and a second power signal;
an integrated circuit (IC) coupled to the Ethernet network connector, wherein the IC comprises:
an Ethernet physical layer (PHY) module;
a power management module;
a direct connection module that directly connects the Ethernet network device to the Ethernet network connector with no intervening magnetic transformer, wherein the direct connection module:
passes the received data signal(s) to the Ethernet PHY;
senses a current associated with each twisted pair;
actively balances the current associated with each twisted pair; and
passes the received plurality of power signals to the power management module, wherein the power management module at least partially powers the Ethernet network device from the received plurality of power signals, the direction connection module further comprising:
an insertion loss control circuit coupled to the direct connection module that determines an insertion loss limit based on an amplitude property of the Ethernet power signal; compares the insertion loss control limit to a sampled common mode signal; and balances the plurality of power signals according to the comparison.
16. The Ethernet network device of claim 15 , wherein:
the Ethernet network connectors comprises an RJ45 connector; and
the four twisted pairs comprise conductors 1 and 2 ; 3 and 6 ; 4 and 5 ; and 7 and 8 ;
the first power signal utilizing conductors 1 , 2 , 3 , and 6 ; and
the second power signal utilizing conductors 4 , 5 , 7 , and 8 .
17. The Ethernet network device of claim 15 , wherein the first power signal and second power signal each do not exceed about 17 watts.
18. The Ethernet network device of claim 15 , wherein the received power signal does not exceed 57 volts.
19. The Ethernet network device of claim 15 , wherein the Ethernet PHY module implements 10 Mbps, 100 Mbps and 1 Gbps physical layer functions.
20. The Ethernet network device of claim 15 , wherein the IC further comprises an Ethernet media access controller (MAC) wherein the Ethernet PHY and Ethernet MAC implement hardware layers of an Ethernet protocol stack.
21. The Ethernet network device of claim 15 , wherein the Ethernet network device comprises at least one device selected from the group consisting of:
a voice over internet protocol (VoIP) telephone;
an Ethernet router;
an Ethernet switch;
a printer;
a data server;
an Ethernet enabled camera;
a wireless access point;
a playback device;
a portable computing device;
a personal data assistant;
a wireless terminal;
a graphics display; and
an audio interface.
22. The Ethernet network device of claim 15 , wherein the plurality of power signals are provided to the Ethernet network from a power sourcing equipment (PSE), and wherein the PSE determines whether the Ethernet network device is IEEE 802.3af compliant.
23. The Ethernet network device of claim 15 , wherein the direct connection module further comprises a power device controller.
24. The Ethernet network device of claim 15 , wherein direct current (DC) blocking capacitors couple the Ethernet PHY module to the received signal.