Abstract: A sampling capacitor structure, which includes a Faraday Shield that can be switched between various nodes. In a switched capacitor circuit, this sampling capacitor structure allows for differential charging of the sampling capacitor while minimizing the effects of any parasitic stray capacitor. Furthermore, with appropriate switching of the Faraday Shield, once the differential charge sampling circuit samples the differential signal, this sampled differential charge can then be transferred to a downstream single-ended circuit, such as an integrator, without any loss of signal.

Abstract: A pipeline analog to digital converter includes a “k” number of stages and an output data register. A first stage of the “k” number of stages is configured to receive an analog differential input signal and produce a first digital output and a first single ended analog output. A second stage of the “k” number of stages is configured to receive the first single ended analog output and produce a second digital output. The output data register is configured to generate an output digital value based on the first and second digital outputs.

Abstract: An electronic reference-signal generation system includes a supply invariant bandgap reference system that generates one or more bandgap reference signals that are substantially unaffected by bulk error currents. In at least one embodiment, the bandgap reference generates a substantially invariant bandgap reference signals for a range of direct current (DC) supply voltages. Additionally, in at least one embodiment, the bandgap reference system provides substantially invariant bandgap reference signals when the supply voltage varies due to alternating current (AC) voltages. In at least one embodiment, the bandgap reference system generates a bandgap reference voltage VBG, a “proportional to absolute temperature” (PTAT) current (“iPTAT”) and a “zero dependency on absolute temperature” (ZTAT) current (“iZTAT”) that are substantially unaffected by variations in the supply voltage and unaffected by a bulk error current.

Abstract: A auxiliary power supply having a selectable operating mode raises efficiency of a switched-power converter. By selectably controlling the input/output behavior of the auxiliary power supply receiving a voltage from an auxiliary winding of one of the power converter magnetic elements, more efficient operation of the auxiliary power supply over the full variation range of the input line voltage is achieved. By selecting the operating mode according to the relationship between the required auxiliary power supply output and the voltage available across the auxiliary winding under current operating conditions, the turns ratio of the auxiliary winding and other circuit parameters can be optimized for efficiency. Selection of the operating mode may be made by detecting the output or input voltage of the multiplier, and the selection may be performed under hysteretic control so that the variation in auxiliary power supply output voltage is reduced dynamically.

Abstract: An electronic reference-signal generation system includes a supply invariant bandgap reference system that generates one or more bandgap reference signals that are substantially unaffected by bulk error currents. In at least one embodiment, the bandgap reference generates a substantially invariant bandgap reference signals for a range of direct current (DC) supply voltages. Additionally, in at least one embodiment, the bandgap reference system provides substantially invariant bandgap reference signals when the supply voltage varies due to alternating current (AC) voltages. In at least one embodiment, the bandgap reference system generates a bandgap reference voltage VBG, a “proportional to absolute temperature” (PTAT) current (“iPTAT”) and a “zero dependency on absolute temperature” (ZTAT) current (“iZTAT”) that are substantially unaffected by variations in the supply voltage and unaffected by a bulk error current.

Abstract: A temperature and process-stable magnetic field sensor bias current source provides improved performance in Hall effect sensor circuits. A switched-capacitor sensing element is used to sense either a reference current or the bias current directly. A current mirror may be used to generate the bias current from the reference current, and may include multiple current source transistors coupled through corresponding control transistors that are switched using a barrel shifter to reduce variations in the bias current due to process variation. The current mirror control may be provided via a chopper amplifier to reduce flicker noise and the current mirror control voltage may be held using a track/hold circuit during transitions of the chopper amplifier to further reduce noise due to the chopping action.

Abstract: A temperature and process-stable magnetic field sensor bias current source provides improved performance in Hall effect sensor circuits. A switched-capacitor sensing element is used to sense either a reference current or the bias current directly. A current mirror may be used to generate the bias current from the reference current, and may include multiple current source transistors coupled through corresponding control transistors that are switched using a barrel shifter to reduce variations in the bias current due to process variation. The current mirror control may be provided via a chopper amplifier to reduce flicker noise and the current mirror control voltage may be held using a track/hold circuit during transitions of the chopper amplifier to further reduce noise due to the chopping action.

Abstract: A power-optimized analog-to-digital converter (ADC) input circuit provides for optimized power consumption versus performance. The first amplifier stage of the ADC is provided by a plurality of amplifiers that are selectably enabled to provide a particular bandwidth and noise performance level. The selection of the combination of enabled amplifiers may be made in conformity with the sample rate of the converter and the amplifiers may have evenly-weighted bias currents, or unevenly weighed bias currents and may be optimized for their particular use in combinations for bandwidth and 1/f noise corner performance. The outputs of the amplifiers are combined in a combiner circuit, which may be a discrete-time chopping amplifier that receives charges from a plurality of capacitors that sample each enabled amplifier output.

Abstract: A voltage isolation buffer, including a pilot channel having a first Hall effect element and a data channel having a second Hall effect element is disclosed. The pilot channel is preferably AC coupled, and the data channel is preferably DC coupled. The voltage isolation buffer may include a calibration engine, which may be configurable to calibrate the voltage generated by the second Hall effect element based on the information from the first Hall effect element. A bi-directional voltage isolation buffer is also disclosed, including a first integrated circuit and a second integrated circuit. The first integrated circuit includes a DC coupled Hall effect sensor and an AC coupled Hall effect sensor. The second integrated circuit includes an AC coupled Hall effect sensor and a DC coupled Hall effect sensor.

Abstract: A voltage isolation buffer, comprising a pilot channel having a first Hall effect element and a data channel having a second Hall effect element is disclosed. The pilot channel is preferably AC coupled, and the data channel is preferably DC coupled. The voltage isolation buffer may comprise a means for calibration, which may be configurable to calibrate the voltage generated by the second Hall effect element based on the information from the first Hall effect element. A bi-directional voltage isolation buffer is also disclosed, comprising a first integrated circuit and a second integrated circuit. The first integrated circuit comprises a DC coupled Hall effect sensor and an AC coupled Hall effect sensor. The second integrated circuit comprises an AC coupled Hall effect sensor and a DC coupled Hall effect sensor.

Abstract: An improved bandgap voltage reference circuit for providing a stable reference output voltage, useful in circuits associated with power supply voltage operations as low as approximately 1.3 Volts. The &Dgr;VBE generator is comprised of a pair of bipolar transistors operating at different current densities. Resistors in series with the transistors, in conjunction with an operational amplifier and current sources, produce a larger Voltage drop proportional to the &Dgr;VBE of the transistors. Output from the operational amplifier is connected to the base of a third bipolar transistor. The third bipolar transistor is provided as the bandgap voltage output device.

Abstract: An apparatus is provided for automatically and dynamically adjusting a frequency division factor of a clock divider situated in the feedback loop of a phase-locked loop (PLL). The frequency division factor is modified based on changes in the input signal frequency forwarded to the PLL. If the input signal frequency increases, the decision circuit coupled to the input of the voltage controlled oscillator records that change as an encoded digital signal. That signal will accordingly modify the current frequency division factor dependent on current division factor as well as the current input signal frequency. The decision circuit can be modeled as an A/D converter, and the control unit placed between the decision circuit and the clock divider can be modeled as a state diagram. Each state of the state diagram is indicative of a frequency division factor, or a change in that division factor, wherein the coded digital signal indicates possible change from one state to another.

Abstract: An integrated circuit apparatus and method is provided for utilizing voltage dividers and differential amplifiers. An apparatus and method for dividing a voltage with a resistor voltage divider and for employing the voltage divider in an integrated circuit. The resistor voltage divider utilizes inaccessible compensation taps that are placed between nonlinearly spaced output taps. The compensation taps reduce the impact of tap resistance on the voltage divider transfer function. The number of inaccessible compensation taps placed between output taps is dependant upon a chosen tap density that is substantially maintained across the body of the resistor voltage divider. The resistor may be used in integrated circuits employing amplifiers, such as volume control circuitry. A differential amplifier is provided with an input common mode feedback loop that compensates for signal distortion due to a common mode signal.

Abstract: An apparatus and method is provided for dividing a voltage with a resistor voltage divider and for employing the voltage divider in an integrated circuit. The resistor voltage divider utilizes inaccessible compensation taps that are placed between nonlinearly spaced output taps. The compensation taps reduce the impact of tap resistance on the voltage divider transfer function. The number of inaccessible compensation taps placed between output taps is dependant upon a chosen tap density that is substantially maintained across the body of the resistor voltage divider. The resistor may be used in integrated circuits employing amplifiers, such as volume control circuitry.

Abstract: A self-calibrated analog-to-digital converter with a corrected output includes an analog modulator (18) for receiving an analog input voltage and outputting a pulse train having a value proportional to the analog input voltage. The pulse train is filtered by a digital filter (20) which has the output thereof input to a calibration module (24). The calibration module (24) is controlled by a calibration control circuit (28) and is operable to correct the output to account for offset and gain errors. Prestored calibration parameters in a register (30) are utilized for this compensation. In a self-calibration mode, the control circuit (28) is operable to control a calibration multiplexer (12) to select a zero-scale input voltage on a terminal (16) and a full-scale reference voltage on a terminal (14) for input to the modulator (18).

Abstract: Hall-effect position sensor apparatus is disclosed which senses the position of a moving body and provides an output signal indicative of the position of the moving body. The apparatus includes a predetermined number of Hall-effect sensors which are positioned in a straight line and in operating proximity to a moving body made of a ferromagnetic material. A permanent magnet is operatively positioned such that the Hall-effect sensors lie in the magnetic field produced by the magnet while the moving body provides a portion of the path comprising the magnetic excitation circuit with the permanent magnet. The moving body includes portions devoid of ferromagnetic material, which causes a change in the magnetic field.