Abstract: Technique for controlling a circuit that converts an AC input voltage into a DC output voltage using transistors arranged in first and second transistor pairs. Each transistor of the first pair is controlled in accordance with polarity of the AC input voltage. Each transistor of the second pair is controlled based on a difference between the AC input voltage and the DC output voltage.

Abstract: Technique for controlling a circuit that converts an AC input voltage into a DC output voltage using transistors arranged in first and second transistor pairs. Each transistor of the first pair is controlled in accordance with polarity of the AC input voltage. Each transistor of the second pair is controlled based on a difference between the AC input voltage and the DC output voltage.

Abstract: Circuits and methods for detecting the presence of a powered device in a powered network connection and removing power from the powered network connection when no powered device is present are disclosed. The circuits and methods involve applying a time-varying voltage signal into an analog amplifier circuit that converts the voltage into a current indicative of the impedance of the connection. The analog amplifier circuit may be implemented with a dual-output trans-conductance amplifier that provides a digital voltage to indicate the removal of the powered device from the powered network connection.

Abstract: A Power over Ethernet (PoE) system having a Power Sourcing Equipment (PSE) and a Powered Device (PD) configured for interacting over four pairs of wire provided for supplying power from the PSE to the PD. The PSE and the PD are configured to perform separate PD classification procedures over first and second 2-pair sets to support PoE operations that are not defined by the IEEE 802.3af standard.

Abstract: A novel system and methodology for controlling an output of Power Sourcing Equipment in a Power over Ethernet system based on a current limit threshold. The PSE has an auto-zero circuit for comparing a monitored output current of the PSE with the current limit threshold to control the output of the PSE.

Abstract: Novel system and methodology for distinguishing a Network Interface Card (NIC) from a short circuit condition in a Power over Ethernet (PoE) system. A system for providing power to a powered device (PD) includes a PD probing circuit that generates a detection signal supplied to a device being probed and determines a response signal produced in response to the detection signal, and a control circuit that determines a detection value based on the response signal. The control circuit detects a short circuit if the detection value is in a first predetermined range, and detects a NIC if the detection value is in a second predetermined range outside of the first predetermined range.

Abstract: Novel system and methodology for detecting a Powered Device (PD) in a Power over Ethernet (PoE) system. A PD probing circuit generates a detection signal supplied to the PD and determines a PD response signal produced in response to the detection signal. Based on the PD response signal, the control circuit determines a detection value for identifying the PD. In particular, the control circuit concludes that the PD is a device satisfying a PoE standard if the detection value is in a first predetermined range, and concludes that the PD is a legacy PD device if the detection value is in a second predetermined range outside of the first predetermined range.

Abstract: Novel circuitry and methodology for providing data communication between a power supply device and a powered device in a system for supplying power over a communication link. The power supply device, such a device for supplying power over Ethernet, receives from the powered device detection information for detecting the powered device and classification information for determining a power level of the powered device. Information circuitry may be provided for handling information presented by the powered device in addition to the detection and classification information.

Abstract: Novel circuitry and methodology for detecting a Powered Device (PD) in a system for providing power to the PD. PD detection circuitry detects the PD in a first mode by providing detection current to probe the PD, and in a second mode by providing detection voltage to probe the PD. A control circuit determines that the PD is a valid device if the PD is detected both in the first mode and in the second mode.

Abstract: Circuitry and methodology for providing data transmission in a Power over Ethernet (PoE) system having a Power Sourcing Equipment (PSE) for providing power to a PoE link, and a Powered Device (PD) coupled to the PoE link for receiving the power from the PSE. The PSE and PD support data communication with each other in a common mode between two pairs of lines in an Ethernet twisted pair cable.

Abstract: Circuits and methods for detecting the presence of a powered device in a powered network connection and removing power from the powered network connection when no powered device is present are disclosed. The circuits and methods involve applying a time-varying voltage signal into an analog amplifier circuit that converts the voltage into a current indicative of the impedance of the connection. The analog amplifier circuit may be implemented with a dual-output trans-conductance amplifier that provides a digital voltage to indicate the removal of the powered device from the powered network connection.

Abstract: Method and apparatus for performing a TDI function with a plurality of electrical signals. A first step of the method stores, during individual ones of a first plurality of consecutive time intervals, a sample of a first electrical signal. A second step of the method equilibrates, during individual ones of a second, subsequent plurality of time intervals, one of the stored samples with a stored sample of a second electrical signal. Subsequent to each of the steps of equilibrating, an electrical signal is outputted that has a magnitude expressive of the equilibrated stored samples. The equilibration is achieved by shorting storage capacitors (C.sub.1, C.sub.2, C.sub.3) together to effectively sum coherent signals and incoherent noise. The charge sum is stored on a capacitance that is effectively doubled from either detector channel operating individually.

Abstract: A current mirror circuit 10 is coupled to a first and a second photodetector 18 and 20 and differentially couples together the two photodetectors to an amplifier 12 such that a resulting differential output current is independent of the intrinsic responsivity difference between the two photodetectors. The circuit includes a first transistor 14 having an input terminal coupled to an output terminal of the first photodetector and a second transistor 16 having an input terminal coupled to an output terminal of the second photodetector. A capacitance 22 is coupled between a control terminal of the first transistor and a control terminal of the second transistor, the control terminal of the first transistor further being coupled to the input terminal of the first transistor. A first switch 24 is coupled between the control terminal of the second transistor and the input terminal of the second transistor.

Abstract: A read-out amplifier (200) for a photovoltaic detector (201) employs an integrating amplifier (203) with capacitor feedback (230 ) during a self-calibrating active load (205, 240) to minimize debiasing of the photovoltaic detector during its operation. The self-calibrating active load reduces the effect of noise and threshold nonuniformities of the semiconductor devices (202, 203, 204, 205) used in the read-out amplifier circuitry.