Abstract: A current sensing circuit may include a shunt resistance through which current to be sensed travels. A first and a second differential amplifier may each provide an amplified output of the voltage across the shunt resistance. A switching system may deliver a current sensing signal output based on the amplified output of the first differential amplifier when the common mode voltage across the shunt resistance is low and based on the amplified output of the second differential amplifier when the common mode voltage across the shunt resistance is high. The first differential amplifier may provide its lowest output DC offset voltage when the common mode voltage is low, while the second differential amplifier may provide its lowest output DC offset voltage when the common mode voltage is high. The first and second differential amplifiers may both have a low common mode voltage rejection ratio, such as a ratio of less than 40 db at the switching frequency of switches that control the current that is sensed.

Abstract: Method and system for measuring the resistance of a resistive structure having at least three nodes. A first calibration signal is determined by measuring a voltage at an output of the resistance structure when no calibration current is injected into a third node between the first and second nodes of the structure. A calibration current is then injected into the third node and a second calibration signal is determined. The absolute value of the difference between the first calibration signal and the second calibration signal is determined, the absolute value being proportional to a product of the resistance of the resistive structure and the calibration current.

Abstract: A power control system includes an event data bus configured to carry event information. Several power supply managers are coupled to the same event bus. Each power supply manager has one or more point of load (POL) regulators assigned to it. Each power supply manager communicates event information with other POL power supply managers over the event data bus.

Abstract: A Powered Device (PD) in a PoE system has two input channels, each being coupled to a separate Power Sourcing Equipment (PSE) for increased reliability. A first PD controller is coupled to the first channel to perform hand-shaking and closes a first Power Good (PWRGD) switch when the PoE voltage is detected on the first channel. A second PD controller is coupled to the second channel to perform hand-shaking and closes a second PWRGD switch when the PoE voltage is detected on the second channel. A diode bridge couples both channels to a single regulating power supply that supplies power to a load. Auxiliary switches are controlled by the PWRGD signals so that only the first channel or the second channel is coupled to the diode bridge in the event that both channels receive the respective PoE voltages. Therefore, hot standby is provided using only one power supply.

Abstract: In one embodiment, a current sensing circuit corrects for the transient and steady state temperature measurement errors due to physical separation between a resistive sense element and a temperature sensor. The sense element has a temperature coefficient of resistance. The voltage across the sense element and a temperature signal from the temperature sensor are received by processing circuitry. The processing circuitry determines a power dissipated by the sense element, which may be instantaneous or average power, and determines an increased temperature of the sense element. The resistance of the sense element is changed by the increased temperature, and this derived resistance Rs is used to calculate the current through the sense element using the equation I=V/R or other related equation. The process is iterative to continuously improve accuracy and update the current.

Abstract: A common mode bias circuit may include a weak common mode bias generator and a common mode bias capacitance. During a first state of the common mode bias circuit, the weak common mode bias generator may be coupled to the common mode bias capacitance and may impart to them a predefined common mode signal level. During a second state of the common mode bias circuit, the common mode bias capacitance may be coupled to differential inputs of an amplifier in a manner that establishes an input common mode level for the amplifier.

Abstract: An apparatus and method for a Universal Serial Bus (USB) isolating device. An USB isolating device includes a downstream facing circuit and a upstream facing circuit. The downstream facing circuit is coupled to a peripheral device via a first pair of signals and is configured for detecting a speed at which the peripheral device is operating based on a first voltage configuration on the first pair of signals. The upstream facing circuit is coupled to the downstream facing circuit and a host/hub via a second pair of signals and is configured for communicating with the downstream facing circuit on the speed of the peripheral device and adaptively creating a second voltage configuration on the second pair of signals to facilitate the host/hub to adapt to the speed of the peripheral device.

Abstract: A method of manufacturing integrated circuit (IC) devices includes the steps of providing a first frame that has openings each having a perimeter with shaped notches, placing a first die in at least one of the openings, and placing a second frame over the first frame. The second frame has a first partial dam bar with a first shaped tip that fits into a first shaped notch of the first frame. The method also includes the step of placing a third frame over the second frame. The third frame has a second partial dam bars with a second shaped tip that fits into a second shaped notch of the first frame. Each perimeter and the respective first and second partial dam bars cooperate to form a continuous dam completely encircling the die within the respective opening.

Abstract: Power Sourcing Equipment (PSE) provides a PoE supply voltage over data wires to a Powered Device (PD). A PSE controller controls a first FET that couples the PoE voltage to the data wire pairs and controls a second FET that couples the data wire pairs to the spare wire pairs. Upon powering up, the PSE controller keeps the two FETs open and performs a detection routine on any devices connected to the data pairs and spare pairs. If a PoE-compatible PD is detected as being coupled to the data pairs, the first switch is closed. If it is determined that the PoE voltage should also be coupled to the spare pairs, the second FET is also closed. The method prevents the PoE voltage from being applied to the spare pairs when the device connected to the spare pairs is not PoE compatible and maintains backwards compliance with IEEE PoE PDs.

Abstract: Novel circuitry and methodology for controlling a step up-step down switching regulator that produces a regulated output signal at an output node in response to an input signal at an input node, and has an inductive device, a plurality of switching circuits for providing connection of the inductive device to the input and output nodes and a ground node, and a switch control circuit for driving the switching devices so as to enable the power supply system to operate in a boost mode to increase the input signal, in a buck mode to decrease the input signal, and in a buck-boost mode when a difference between the input signal and the output signal is within a predetermined range. Buck-boost latch circuitry is provided for latching a transition between the buck mode and the buck-boost mode, or between the boost mode and the buck-boost mode based on a predetermined condition.

Abstract: Method and system for configuring a serial interface. The system includes one or more input nodes each coupled to a corresponding serial bus. One or more output nodes are coupled to a respective serial bus, each output node having a respective driver. A voltage detection circuit determines the voltage at a configuration node. Mode of serial bus operation is based on the voltage level detected at the configuration node. In at least one mode of serial bus operation, the configuration node is used as a mode select input and power source for at least one output driver.

Abstract: Methods and systems for sampling a differential signal. The sampling circuit includes a differential input and a differential output. A logic control block, which is powered by VDD and VSS sources, controls the state of switches used to sample and store differential signals. The logic control block is AC coupled to the switches. The sampling circuit is configured to sample a common mode voltage at the differential input of a level that exceeds that of the VDD and VSS sources.

Abstract: A method and interface for serial communication is provided. The interface includes a differential input/output having a first node and a second node. There are several input/output nodes arranged to receive serial interface signals. The interface includes a transmitter configured to drive a twisted pair cable at the differential input/output. There is a receiver coupled to the differential input/output that includes a window comparator. A serial port control unit provides serial data to the transmitter and receives serial data from the receiver. The serial communications interface transmits serial data to and receives serial data from a second serial communications interface independent of a reference clock and is galvanically isolated from the second serial communications interface.

Abstract: A single-balanced balun mixer circuit includes a balun with a center tap connected to a differential pair with a tail resistor. The balun receives a first input signal and a second signal at the single-ended input terminal and the center tap, respectively. Such a balun mixer may be used as an up-converter mixer by supplying a baseband or intermediate signal at the center tap and a local oscillator (LO) signal at the single-ended input terminal.

Abstract: A device and method of providing any one of a plurality of desired levels of a regulated signal output to a load is described, wherein each desired level is a function of a corresponding reference signal. The device is configured and the method is designed to (1) store each desired level of the regulated signal output on a switchable storage device; and (2) selectively switch the correct storage device to the output when switching from one regulated state to another so as to establish the desired level of regulated signal output.

Abstract: A method and an ADC circuit use multiple SD modulations on an analog value and apply digital post-processing of the pulse density modulation (PDM) streams from the SD modulations obtaining a higher resolution in the digital output value for a given oversampling ratio. SD ADC does not face the constraint of conversion time doubling for each additional bit of resolution. In one implementation, an SD ADC includes conversions in SD phase and a resolution-boosting phase. During SD phase, MSBs of the digital output value are generated from the sampled analog value using a first SD conversion. At the end of SD phase, the sampled analog value is reduced to “residual quantization error,” which remains in a capacitor of an integrator of SD ADC. In resolution-boosting phase, the LSBs of the digital output value are generated from residual quantization error using a second SD conversion that provides at least the LSBs.

Abstract: A method and a circuit achieve fully isolated sampling of bipolar differential voltage signals. The isolated sampling network is suitable for applications in which sampling signals far outside of the supply voltages are desired. A sampling network of the present invention may sample a differential signal between voltages ?VDSMAX and VDSMAX, even with common mode voltages that exceed the supply voltage (e.g., an input stage of an ADC). The bipolar isolated input sampling network may include a polarity comparator and sampling switches that operate as rectifiers. Rectification ensures that a unipolar sampling network needs only to sample signals of predetermined voltage levels.

Abstract: An interface circuit for driving a fully-differential circuit has a first circuit configured to decrease the voltage at its output in response to an increase in an average value of first and second input voltages. A first network receives the first input voltage and the output voltage of the first circuit to provide a first output voltage for driving the fully-differential circuit. A second network receives the second input voltage and the output voltage of the first circuit to provide a second output voltage for driving the fully-differential circuit. An impedance ratio of the first network is substantially matched to an impedance ratio of the second network.

Abstract: A flyback converter uses primary side sensing to sense the output voltage for regulation feedback. A comparator on the primary side detects whether the output voltage has exceeded a predetermined regulated voltage by a first threshold to detect an over-voltage condition, resulting from a current generated by the converter exceeding the load current. Triggering of the comparator causes the converter to enter a non-switching sleep mode, whereby the output voltage droops over a period of time. When the output voltage has drooped below the predetermined regulated voltage by a second threshold, a synchronous rectifier is controlled to turn on, then off, to generate a pulse in the primary winding. Upon detection of the pulse, the sleep mode is terminated, and normal operation resumes until a regulated voltage is achieved or until the first threshold is again exceeded by the output voltage.

Abstract: In one embodiment, a regulator circuit for generating a regulated output voltage Vout has an error amplifier using a pair of bipolar transistors at its front end. The error amplifier compares the regulated output voltage to a reference voltage Vref. A precision current source draws a first current through a user-selected set resistance to generate the desired Vref. The regulator circuit controls a power stage to cause Vout to be equal to Vref. The base current into one of the bipolar transistors normally distorts the current through the set resistance. A base current compensation circuit is coupled to the current source to adjust the first current by a value equal to the base current to offset the base current. Therefore, Vref is not affected by the base current. The error amplifier may be in a linear regulator or a switching regulator. The compensation circuit may be used in other applications.