Abstract: Control device for a power over Ethernet system having multiple power source devices comprises plural control circuits and a signal bus connecting them. Each control device connects plural power source devices and plural port switches, which controls power supply to a port to be connected by a power consuming device. Detection circuit detects at least one power supply state combination. Control signal generator picks up a power control combination signal corresponding to a detected power supply state combination from a power supply to power control look-up-table, upon change in the power supply state and provides the power control signals to corresponding port switches.

Abstract: Power over Ethernet system having multiple power source devices comprising a control device that controls power distribution to a plurality of communication ports. In the control device, a master controller provides a power supply to power consumption look-up-table to a plurality of control circuits in various manners via a series bus. When one power source device shuts down, each control circuit can rapidly shut off selected port switches connected thereto.

Abstract: Control device for power over Ethernet system having multiple power source devices controls power distribution to a plurality of communication ports. Master controller provides a power supply to power consumption look-up-table to a plurality of control circuits in various manners via a series bus. When one power source device shuts down, each control circuit can rapidly shut off selected port switches connected thereto.

Abstract: A common mode voltage level shifting and locking circuit is provided. The common mode voltage level shifting and locking circuit includes an operational amplifier, a source follower, a first feedback circuit, and a second feedback circuit. The operational amplifier generates a first common mode voltage. The source follower shifts the first common mode voltage to generate a second common mode voltage. The first feedback circuit generates a first control signal according to the second common mode voltage. The operational amplifier adjusts the first common mode voltage according to the first control signal. The second feedback circuit generates a second control signal according to an external reference voltage provided by a next stage circuit. The source follower adjusts the second common mode voltage according to the second control signal such that the next stage circuit reaches a maximum input common mode range.

Abstract: A common mode voltage level shifting and locking circuit is provided. The common mode voltage level shifting and locking circuit includes an operational amplifier, a source follower, a first feedback circuit, and a second feedback circuit. The operational amplifier generates a first common mode voltage. The source follower shifts the first common mode voltage to generate a second common mode voltage. The first feedback circuit generates a first control signal according to the second common mode voltage. The operational amplifier adjusts the first common mode voltage according to the first control signal. The second feedback circuit generates a second control signal according to an external reference voltage provided by a next stage circuit. The source follower adjusts the second common mode voltage according to the second control signal such that the next stage circuit reaches a maximum input common mode range.

Abstract: A power source equipment for power over Ethernet system comprising a plurality of power source devices, each configured to determine, after having determined the power source device is connected by an external device without a powered device (PD) signature, whether another power source device is connected by a power device with a PD signature. If the determination is positive, the two power source devices are determined having been connected by the same PD and power is supplied to the PD by the two power source devices.

Abstract: The present invention relates to device and method for detecting powered devices connected to a power source equipment in a Power over Ethernet system that provides multiple signal/power channels. A series of inspection signals including one discriminative signal is applied to the respective channels and response signals to the discriminative signal and other detection signals are compared in order to determine whether multiple channels are connected to one single powered device.

Abstract: An inspection device to determine whether a device connected to a Power over Ethernet system is suited for being powered, is configured to apply an inspection signal to the device and to measure a response signal thereto. The inspection signal includes a first, second, third and fourth voltage, wherein the first voltage and the third voltage are substantial the same and the second voltage and the fourth voltages are substantial the same, and an application period for applying the fourth voltage is sum of the application period for the second voltage and an extension period. The inspection device determines that the device is not suitable for being powered if a response signal exceeds predetermined ranges. A method to perform these inspections is also disclosed.

Abstract: A gain circuit for power sourcing equipment of Power over Ethernet is disclosed and provides a guard band for the input offset voltages of its operational amplifier. The guard band may be represented by a voltage value and may be set to be greater than the maximum input offset voltage of the input terminals of the operational amplifier. In some embodiment, the guard band allows the voltage of the negative input terminal of the operational amplifier to be greater than 0 V without sacrificing the gain precision.

Abstract: A power source equipment for Power over Ethernet system continues to inspect power consumption of all connecting ports, in order to adjust power allocation to the communication ports. When the power consumption of a particular connecting port shows a trend of increase, its power allocation is increased; otherwise, decreased. After a total power allocation is decreased, additionally available power may be generated and provided to an additional communication port. A method for adjusting the power allocation is also disclosed.

Abstract: A power source equipment for Power over Ethernet system provides an adjustment mechanism for the maximum allowable power of communication port connected to the power source, whereby when a device requests to join as a powered device but a maximum allowable power of a corresponding class is greater than the difference of the total supplied power and the sum of maximum allowable power designated to the then connected powered devices, the maximum allowable power of the respective powered devices may be adjusted, to generate sufficient allowable power for the requesting device. A power supplying method using the adjustment mechanism is also disclosed.

Abstract: An impendence tuning apparatus is disclosed. The impendence tuning apparatus includes an operation amplifier, a reference resistor, a tuned resistor, a switching module, a current generator, a current detector and a controller. A first input terminal of the operation amplifier receives a basic voltage and the second terminal of the operation amplifier coupled to a first end. The switching module receives a control and coupled the first end to the tuned resistor or the reference resistor accordingly for generating a tuned current or a reference current separately. The current generator receives and mirrors the reference current or the tuned current to generate a first current and a second current. The current detector receives the first and the second currents and outputs current values the first and the second currents to the controller. The controller tunes an impendence of the tuned resistor according to the first and the second currents.

Abstract: An echo canceller and an echo cancellation method are provided. In the echo cancellation method, a transmitting data sequence is received, and M taps are provided accordingly. In addition, the M taps are received, and N taps are output according to an echo distribution information, in which the M and N are natural numbers, and M>N. Besides, the N taps are multiplied by N tap coefficients respectively to generate N products. Further, the N products are summed up to generate an echo cancellation signal. Thereby, the cost of the echo cancellation is decreased.

Abstract: A network transmitting apparatus and a power saving method thereof are provided. The network transmitting apparatus includes a chip, a transformer, and a power regulating unit. The chip includes a detecting and controlling unit, an analog circuit, and a digital circuit. The detecting and controlling unit receives a received signal and detects the received signal and a state of the chip to generate a first control signal. The transformer has a first side coupled to the chip and a second side. The power regulating unit coupled to the detecting and controlling unit and a center tap of the first side of the transformer is used for receiving a voltage, generating a first regulated voltage according to the first control signal, and connecting the first regulated voltage to the center tap of the first side of the transformer, the analog circuit, and the digital circuit.

Abstract: A transceiver apparatus, a receiver and a power saving method thereof are provided. The receiver includes an analog-to-digital converter, an equalizer, a slicer, a delay unit, a decoder, a select unit and a control unit. The analog-to-digital converter transforms a received signal into a digital signal. The equalizer adjusts the digital signal to generate an equalized signal. The slicer receives and slices the equalized signal and generates a sliced signal. The delay unit delays the sliced signal. The decoder determines whether to decode the equalized signal or not according the control signal. The select unit selects one of the output of the delayed sliced signal and the output of the decoder to be an output signal according to a second control signal. The control unit determines whether to enable the control signal and the second control signal according to the state of the sliced signal and the output signal.

Abstract: A transceiver device and a power saving method thereof are provided. The transceiver device includes a transmitter, a receiver, and a control module. The control module is coupled to the transmitter and the receiver. After the control module lowers the output power of either the transmitter, the receiver, or both of them, the control module checks a signal transmission between the transceiver device and a far-end device is normal or not. When the signal transmission between the transceiver device and the far-end device is abnormal, the control module readjusts the output power of the transmitter, the receiver, or both of them. Thereby, the power consumption of the transceiver device is decreased.

Abstract: An impendence tuning apparatus is disclosed. The impendence tuning apparatus includes an operation amplifier, a reference resistor, a tuned resistor, a switching module, a current generator, a current detector and a controller. A first input terminal of the operation amplifier receives a basic voltage and the second terminal of the operation amplifier coupled to a first end. The switching module receives a control and coupled the first end to the tuned resistor or the reference resistor accordingly for generating a tuned current or a reference current separately. The current generator receives and mirrors the reference current or the tuned current to generate a first current and a second current. The current detector receives the first and the second currents and outputs current values the first and the second currents to the controller. The controller tunes an impendence of the tuned resistor according to the first and the second currents.

Abstract: A transceiver device and a power saving method thereof are provided. The transceiver device includes an attenuation estimation module, a transmitter, and a control module. The attenuation estimation module is coupled to a transmission path for estimating an attenuation value caused when a signal passes through the transmission path. The transmitter is coupled to the transmission path, for outputting a transmission signal. The control module is coupled to the attenuation estimation module and the transmitter. When the attenuation value is smaller than a default value, the output power of the transmitter is adjusted to be lower. Thereby, the power consumption of the transceiver device is decreased.

Abstract: A transceiver device and an impedance matching method are provided. In the impedance matching method, a plurality of matching modes is set. Each matching mode includes a default impedance and a corresponding default power. In addition, one of the matching modes is selected for outputting a transmission signal to a load. Besides, a response signal derived from the transmission signal is received. Further, whether the default impedance is matched with an impedance of the load or not is determined according to a parameter of the response signal. Thereby, the echo signal can be restrained from being generated.

Abstract: A line transceiver apparatus for multiple transmission standards including a operational amplifier (OP-AMP), a transformer unit, a first variable resistor unit to a sixth variable resistor unit, and a variable resistor control unit is provided. The first resistor and the second resistor are coupled between transmission nodes of the line transceiver apparatus and input nodes of the OP-AMP, and the load nodes of the transformer unit are receiving nodes of the line transceiver apparatus. The variable resistor control unit adjusts the impedances of the first variable resistor unit to the sixth variable resistor unit according to a transmission standard selection signal so as to enable the line transceiver apparatus to support multiple transmission standards.