Abstract: In an electronic system, a frequency modulator manages clock signals for electromagnetic interference (EMI) reduction. The illustrative frequency modulator comprises a core oscillator, and a clock divider coupled to the core oscillator that modulates frequency of the core oscillator and deterministically spreads clock spectral components of a digital clock signal whereby electromagnetic interference (EMI) is reduced. The frequency modulator further comprises a circuit coupled to the clock divider that receives the digital clock signal, combines the digital clock signal with a data bitstream for transmission across an isolation barrier, and resynchronizes to the digital clock signal.

Abstract: An open collector/open drain interface, such as I2C interface between two or more integrated circuit devices, employs isolation techniques to provide electrical isolation of a digital signal for transmission of the signal between the devices. Uni-directional isolator channels are utilized to transmit bidirectional digital signals, and a selection of an isolator channel operating in an intended transmission direction is performed by direction control logic. Edge detection logic is utilized to determine changes in edges of a digital signal, thus determining a transmitting device and a transmission direction. The direction state is held in a direction state register. This state is held until the appropriate edge is detected on the transmit side, returning the isolator to the idle state. In the idle state neither side of the isolator is in a driven state. During transmission, the digital signal is transmitted through an isolator channel and sent to a receiving device.

Abstract: A network device comprises an interface coupling an electronic device to a differential pair of signal lines, and an integrated active common mode suppression and electrostatic discharge protection circuit coupled to the interface in parallel to differential signal lines of the electronic device.

Abstract: Embodiments disclosed herein describe a network device including a class AB common mode suppression (CMS) circuit coupled in parallel between a line voltage source and a physical layer (PHY) device that provides active EMI suppression and Phy device termination. A network connector is coupled to provide the line voltage source to the class AB CMS circuit. The class AB CMS circuit provides current to the PHY device, terminates open-drain transmit drivers of the PHY device and suppresses common mode noise thereby minimizing electromagnetic interference. In other embodiments, the class AB CMS circuit is coupled in parallel between the network connector and a physical layer (PHY) device. The class AB CMS circuit suppresses common mode noise, and terminates open-drain transmit drivers of the PHY device, thereby minimizing electromagnetic interference.

Abstract: A signal isolator comprises an isolation barrier, a transmitter, a differentiator, and a recovery circuit. The transmitter is coupled to a first side of the isolation barrier and is configured to receive and convert an information signal to a differential signal that encodes information in the information signal in a single transition edge. The differentiator is coupled to a second side that is isolated from the first side of the isolation harrier and differentiates the differential signal. The recovery circuit is coupled to the differentiator and operates to recover an output information signal based on the information in the single transition edge.

Abstract: An interface between USB devices employs isolation techniques to provide electrical isolation of a USB signal for transmission of the USB signal between the devices. Unidirectional isolator channels are utilized to transmit the USB signals, and a selection of an isolator channel operating in an intended direction is performed by either direction control logic or a USB hub function. Logic may be employed to detect a device attempting to initiate a USB signal. The logic operates to enable a transmitter on a receiving side and isolate the USB signal through an isolator channel operating in a transmission direction.

Abstract: Embodiments disclosed herein describe a network interface device including a first powered device controller coupled to first and second power supply lines. A second powered device controller coupled to third and fourth input power supply lines. A dc-dc converter coupled to receive a single signal representing a sum of power signals output by the first and second powered device controllers.

Abstract: A current-mode controller comprises an inductance element, at least one semiconductor switch coupled to the inductance element, and a ramp compensator coupled to sense an indication of current through the inductance element and coupled to control the at least one semiconductor switch that senses current during on-time of the DC-DC converter, infers current during off-time of the DC-DC converter, and determines a slope compensation signal based on the sensed and inferred currents.

Abstract: An interface between USB devices employs isolation techniques to provide electrical isolation of a USB signal for transmission of the USB signal between the devices. Unidirectional isolator channels are utilized to transmit the USB signals, and a selection of an isolator channel operating in an intended direction is performed by either direction control logic or a USB hub function. Logic may be employed to detect a device attempting to initiate a USB signal. The logic operates to enable a transmitter on a receiving side and isolate the USB signal through an isolator channel operating in a transmission direction.

Abstract: A power converter comprises a direct current (DC)-DC converter configured to receive an input voltage in a primary domain, a transformer coupled to and driven by the DC-DC converter and supplying an output voltage in a secondary domain, and a transmission path configured to pass a digital feedback signal through an isolation barrier from the secondary domain to the primary domain.

Abstract: A network interface apparatus is disclosed that includes a connector coupled to a plurality of communication lines. A Physical Layer (PHY) device coupled to the communication lines and to a first ground level. A transient event suppression module coupled between the communication lines and a low impedance path to earth ground. During a transient event the transient event suppression module provides a low impedance path to the earth ground to protect the PHY device from the transient event. A power circuit that delivers power from a second ground level to the PHY device is coupled to the first ground level. The first ground level and the second ground level are coupled to provide a low impedance path during normal operation and high impedance during transient events.

Abstract: In a network device, a connector module comprises a network connector coupled to the connector module in a configuration that transfers power and communication signals and an application connector that comprises serial media independent interface (SMII) pins and power pins. A Power-over-Ethernet (PoE) circuit is coupled between the network connector and the application connector.

Abstract: A semiconductor device comprises an integrated circuit formed on a substrate with a signal interface and at least one isolator capacitor. The integrated circuit comprises a plurality of interleaved inter-metal dielectric layers and interlayer dielectrics formed on the substrate, a thick passivation layer formed on the plurality of the interleaved inter-metal dielectric layers and interlayer dielectrics, and a thick metal layer formed on the thick passivation layer. The thick passivation layer has a thickness selected to be greater than the isolation thickness whereby testing for defects is eliminated. The one or more isolator capacitors comprise the thick metal layer and a metal layer in the plurality of interleaved inter-metal dielectric layers and interlayer dielectrics separated by the thick passivation layer as an insulator.

Abstract: An active clamp device electrically couples first and second nodes in respective first and second supply domains referenced to ground potentials that can be different. The active clamp device comprises first and second active devices controlled by signals respectively referenced to the first and second supply domains that create a short-circuit or low impedance connection between the first and second nodes in normal operation and drive impedance between the first and second nodes high in response to a transient event.

Abstract: A method for transmitting an information signal across an isolation barrier comprises receiving an input signal, preconditioning the input signal according to a modulation function, passing the preconditioned signal through the isolation barrier, and recovering the passed signal according to a demodulation function corresponding to the modulation function, the recovered signal being operative as a feedback signal.

Abstract: Embodiments of the present invention provide a power feed circuit operable to supply an Ethernet power signal to a coupled Ethernet network. This power feed circuit includes a number of input nodes, differential transistor pairs, active control circuits and output nodes. The input nodes receive a first power signal such as that provided by an isolated 48 volt power supply. Each transistor of the differential transistor pairs couples to one input node. These differential transistor pairs produce a second power signal which may be supplied to the Ethernet network. The active control circuits sense the second power signal passed by each transistor and are operable to apply a feedback signal to the differential transistor pairs based on the sensed power signal. At least one twisted pair couples to each differential transistor pair's output node and is operable to pass the Ethernet power signal.

Abstract: Embodiments of the present invention provide a network device operable to receive a network signal that may include both power and data from a coupled network. This network device includes a network connector and an integrated circuit. The network connector physically couples the network device to the network. An optional protection circuit may provide surge protection or incoming network signals received by the network device through the network connector. An optional switching/rectifying circuit sees the output of the protection circuit and is operable to rectify a power signal when contained within the network signal. The integrated circuit further includes a power feed circuit conductively coupled to the protection circuit and the rectifying circuit. This power feed circuit is operable to separate and pass the received data signal to a network physical layer and separate and pass the received power signal to a power management module.

Abstract: An interface between two or more integrated circuit devices employs isolation techniques to provide electrical isolation of a digital signal for transmission of the digital signal between a master device and one or more slave devices. Unidirectional isolator channels are utilized to transmit bidirectional digital signals, and a selection of an isolator channel operating in an intended direction is performed by direction control logic. Logic that monitors read and write transactions operates to determine a desired direction of the digital signal and accordingly directs the digital signal through an appropriate isolator channel.

Abstract: Embodiments disclosed herein provide a network device comprises a transformer with a primary winding and a secondary winding. The primary winding is coupled to receive input signals from a network connector and supply data signals to a physical layer (PHY) module. An inductance boost circuit is coupled to the secondary winding and operable to increase the impedance of the primary winding. In other embodiments, a network device comprises an autotransformer coupled to receive input signals from a network connector and supply data signals to a physical layer (PHY) module. An electronic load coupled in parallel between the autotransformer and the PHY layer module.

Abstract: 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.