Abstract: In one embodiment, a powered device (PD) (402) has a PHY module (410) and a media access controller (419) (MAC), the PD (402) adapted to connect to power sourcing equipment (PSE) via a cable, (408) where the PD (402) is adapted to communicate with and receive power from the PSE via the cable, in accordance with the Power-over-Ethernet (PoE) standard. The PD (402) extracts (413) from the cable (408) a DC signal used to power the PD without using a transformer. Capacitors (420) located in the signal paths between the MAC (419) and the cable (408) support electrical isolation of the MAC (419).

Abstract: One embodiment monitors a line-side electrical current provided by a power sourcing equipment (PSE) port to a powered device (PD), the PSE port having a power-isolation transformer with a primary coil on an isolated side and a secondary coil on a line side. A switching signal having a switching period and a duty cycle is applied to the primary coil of the power-isolation transformer. A value is determined for an electrical current on the isolated side of the power-isolation transformer, conversion is performed between a line-side electrical current value Iout and a corresponding isolated-side peak-current value Ipeak, and the line-side electrical current is indirectly monitored based on the determined isolated-side current value.

Abstract: In one embodiment, a powered device (PD) (402) has a PHY module (410) and a media access controller (419) (MAC), the PD (402) adapted to connect to power sourcing equipment (PSE) via a cable, (408) where the PD (402) is adapted to communicate with and receive power from the PSE via the cable, in accordance with the Power-over-Ethernet (PoE) standard. The PD (402) extracts (413) from the cable (408) a DC signal used to power the PD without using a transformer. Capacitors (420) located in the signal paths between the MAC (419) and the cable (408) support electrical isolation of the MAC (419).

Abstract: In one embodiment, the invention is an apparatus (e.g., an Ethernet switch) having an isolated side and a line side. A line-side connector is connectable to a cable. An isolated-side physical-layer module (1) is electrically coupled to the connector via a signal-isolation transformer and (2) processes signals transmitted over the cable. A line-side power conditioning module (1) is electrically coupled to an isolated-side power switcher via a power-isolation transformer that converts an AC power signal received from the power switcher into a transformed AC power signal and (2) converts the transformed AC power signal into a cable power signal to be supplied via the connector to the cable in order to power a cable-powered device connected to the cable. An isolated-side control module performs a detection function in which the control module determines whether or not a cable-powered device is connected to the cable.

Abstract: Disclosed is a method and apparatus that includes a power supply having a primary coil and a secondary coil. The secondary coil generates an output voltage and a feedback voltage related to the output voltage. The feedback voltage is sampled at a time instant that is digitally controllable. The output voltage is determined from the feedback voltage.

Abstract: A series pass transistor voltage regulator is described having a main power source and an auxiliary power source. When the main power source voltage falls to a level the regulator can no longer use, the regulator seamlessly draws power from the auxiliary source. A voltage dropping circuit of two series-coupled diodes allows for a single feedback control amplifier to control the regulator's pass transistors in series with the main and auxiliary power sources.

Abstract: Disclosed is a method and apparatus that includes a power supply having a primary coil and a secondary coil. The secondary coil generates an output voltage and a feedback voltage related to the output voltage. The feedback voltage is sampled at a time instant that is digitally controllable. The output voltage is determined from the feedback voltage.

Abstract: One embodiment monitors a line-side electrical current provided by a power sourcing equipment (PSE) port to a powered device (PD), the PSE port having a power-isolation transformer with a primary coil on an isolated side and a secondary coil on a line side. A switching signal having a switching period and a duty cycle is applied to the primary coil of the power-isolation transformer. A value is determined for an electrical current on the isolated side of the power-isolation transformer, conversion is performed between a line-side electrical current value Iout and a corresponding isolated-side peak-current value Ipeak, and the line-side electrical current is indirectly monitored based on the determined isolated-side current value.

Abstract: Disclosed is a method and apparatus that includes a power supply having a primary coil and a secondary coil. The secondary coil generates an output voltage and a feedback voltage related to the output voltage. The feedback voltage is sampled at a time instant that is digitally controllable. The output voltage is determined from the feedback voltage.

Abstract: In one embodiment, the invention is an apparatus (e.g., an Ethernet switch) having an isolated side and a line side. A line-side connector is connectable to a cable. An isolated-side physical-layer module (1) is electrically coupled to the connector via a signal-isolation transformer and (2) processes signals transmitted over the cable. A line-side power conditioning module (1) is electrically coupled to an isolated-side power switcher via a power-isolation transformer that converts an AC power signal received from the power switcher into a transformed AC power signal and (2) converts the transformed AC power signal into a cable power signal to be supplied via the connector to the cable in order to power a cable-powered device connected to the cable. An isolated-side control module performs a detection function in which the control module determines whether or not a cable-powered device is connected to the cable.

Abstract: A series pass transistor voltage regulator is described having a main power source and an auxiliary power source. When the main power source voltage falls to a level the regulator can no longer use, the regulator seamlessly draws power from the auxiliary source. A voltage dropping circuit of two series-coupled diodes allows for a single feedback control amplifier to control the regulator's pass transistors in series with the main and auxiliary power sources.