Nxp B.v.

U.S. Philips Corporation

Harry Neuteboom

Dave Sebastiaan Kroekenstoel

Muhammad Kamran

Sergio Andrés Rueda Gómez

Costantino Ligouras

Rinze Ida Mechtildis Peter Meijer

Eise Carel Dijkmans

Edwin Jan Schapendonk

Robert Van Veldhoven

Steven Aerts

Denis Noel

Leon Van Der Dussen

Carel Dijkmans

Ben Kup

Peng Zhao

A method and apparatus are described for bio-impedance measurement using voltage to current conversion. In one example, a bio-impedance transducer includes an input stage to receive a bio-impedance signal having an oscillating voltage from two electrodes, the electrodes being coupled to a body, a resistance across the two electrodes to determine an alternating current of the bio-impedance signal, a gain stage coupled to the resistance to amplify the alternating current, a down converter coupled to the gain stage to convert the amplified alternating current to a direct current bio-impedance signal, and an analog-to-digital converter coupled to the down converter to convert the direct current bio-impedance signal to a digital bio-impedance signal.

Bio-impedance measurement using voltage to current conversion

Embodiments of multi-mode sigma-delta analog-to-digital converter (ADC) circuits and a microphone circuit are disclosed. In an embodiment, a multi-mode sigma-delta ADC circuit includes a pair of operational transconductance amplifiers (OTAs), a filter connected to the pair of OTAs, a quantizer connected to the filter, a differential digital-to-analog converter (DAC) connected to the quantizer, and a controller configured to switch the multi-mode sigma-delta ADC circuit between a single-ended operational mode, a pseudo differential operational mode, and a full differential operational mode to improve common mode rejection (CMR) performance by controlling the pair of OTAs. An output of a microphone and a differential output of the differential DAC are inputted into input terminals of the pair of OTAs.

Multi-mode sigma-delta ADC circuit and microphone circuit having a multi-mode sigma-delta ADC circuit

Embodiments of sigma-delta analog-to-digital converter (ADC) circuits and a microphone circuit are disclosed. In an embodiment, a sigma-delta ADC circuit includes a pair of operational transconductance amplifiers (OTAs), a filter connected to the pair of OTAs, a quantizer connected to the filter, a differential digital-to-analog converter (DAC) connected to the quantizer, and a bias compensation circuit configured to measure a biasing condition of a first OTA of the pair of OTAs and to apply the biasing condition of the first OTA to a second OTA of the pair of OTAs to reduce Total Harmonic Distortion Plus Noise (THD+N) in the sigma-delta ADC circuit. An output of a microphone and a differential output of the differential DAC are inputted into input terminals of the pair of OTAs.

Sigma-delta ADC circuit with bias compensation and microphone circuit having a sigma-delta ADC circuit with bias compensation

A method and apparatus are described for a reconfigurable architecture analog front end architecture for electrochemical sensors. In one example, an analog front end includes an electrode driver stage coupled to electrodes of an electrochemical sensor, and measurement channels coupled to the electrode driver stage to receive an electrode signal from the electrodes of the electrochemical sensor and to generate measurement results, the measurement channels configured to switch configurations to perform different measurements.

Reconfigurable architecture analog front end for electrochemical sensors

Various embodiments relate to a detector circuit, including: a voltage source configured to produce a first voltage on a first output, a second voltage on a second output, and third voltage on a third output, wherein the first voltage is greater than the second voltage and the second voltage is greater than the third voltage; a first switch connected to the second output; a sampling capacitor connected to the switch, wherein the sampling capacitor is charged by the voltage source when the switch is closed; a first comparator with one input connected to the first output and a second input connected to the sampling capacitor; a second comparator with one input connected to the third output and a second input connected to the sampling capacitor; a multiplexer with a plurality of inputs configured to be connected to a plurality of terminals of an external circuit and an output connected to the sampling capacitor, the first input of the first comparator, and the first input of the second comparator; and a controller with inputs connected to the first comparator, the second comparator, and a clock generation unit, wherein the controller is configured to produce control signals to control the first switch and the multiplexer and wherein the controller is configured to produce an output signal indicting the presence of a current leak on one of the plurality of terminals.

Leakage and loading detector circuit

A method for digital-to-analog signal conversion with distributed reconstructive filtering includes receiving a digital code synchronous to a clock signal having a first frequency, determining next states of a plurality of digital-to-analog current elements based on the digital code, combining a plurality of currents to generate an output current, and generating the plurality of currents. Each of the plurality of currents is based on a corresponding control signal of a plurality of control signals. The method includes generating the plurality of control signals based on the next states of the plurality of digital-to-analog current elements. Each of the plurality of control signals selects a first voltage level, a second voltage level, or a transitioning voltage level for use by a corresponding digital-to-analog current element. The transitioning voltage level linearly transitions from the first voltage level to the second voltage level over a predetermined number of periods of the clock signal.

Current digital-to-analog converter with distributed reconstruction filtering

A signal generator includes a first voltage generator, a second voltage generator, an operational amplifier, and an oscillator. The first voltage generator generates a first voltage, and the second voltage generator generates a second voltage. The operational amplifier generates an amplified error signal based on the first voltage and the second voltage, and the oscillator generates a periodic signal based on the amplified error signal. The first voltage generator and the second voltage generator are configured to generate their respective voltages based on the periodic signal. As a result, frequency deviation in the periodic signal may be corrected, for example, without increasing the source current of the oscillator or the gain of the operational amplifier. Also, improved phase noise performance may also be achieved through an increase in loop gain.

Feedback oscillator with multiple switched capacitors

A signal converter includes a first converter, a second converter, a signal generator, and a controller. The first converter generates a first analog signal from a digital signal, and the second converter generates a second analog signal from the digital signal. The signal generator outputs a converted analog signal based on the first analog signal and the second analog signal. The controller generates one or more control signals to change a power supply state of at least one of the first converter and the second converter. The change in power supply state suppress even order harmonics.

System and method for improving matching in a signal converter

Aspects are directed to a wireless communications approach in which a signal is conveyed via one of a number of particular frequency bands. In one example, a tank circuit includes an inductor and multiple capacitive circuits, and a driver circuit includes multiple buffers. One of the buffers is responsive to the input signal and another of the buffers is not responsive to the input signal. The driver circuit is configured to drive the tank circuit through a respective capacitive circuit while coupled to a respective buffer at a node of the inductor. A tuning-drive circuit drives the tank circuit for communicating in one band of a selectably-tunable frequency range. The tuning-drive circuit includes selectable (buffer and capacitor) portions configured to selectively couple to the node, for an overall drive strength and an overall tuning capacitance, and for tuning the tank circuit to a selected frequency band for wireless communication.

Circuit for inductive communications with multiple bands

A wireless receiver is activated periodically to measure the level of received signals. It measures the average received level over a plurality of the activation periods, and enables the supply of power to receiver circuitry dependent on the measured average value. In one embodiment the power is enabled if an increase in the average value is detected which is greater than a predetermined margin. The average value may be measured in a sliding or stepped window. In another embodiment the power is enabled if the level in an activation period exceeds the average value by a predetermined margin.

Power supply control in a wireless receiver

A low power, high dynamic range sigma-delta modulator comprises a quantizer followed by a digital integrator for generating an integrated digital signal from a quantized signal. The output of the digital integrator is coupled to a digital-to-analog converter in the feedback loop of the sigma-delta modulator.

Low power high dynamic range sigma-delta modulator

A device, e.g., a hearing aid, has an electronic circuit for wireless communication of a digital signal. The circuit has a driver driving an RLC tank. The driver has a plurality of inverters whose outputs are coupled to a node of the coil via a respective one of multiple capacitors in the tank. The circuit has a controller that selectively drives one or more of the inverters with the digital signal and connects the inputs of the other inverters to a supply voltage or ground. The tank has a further plurality of series arrangements of a further capacitor and a high-voltage switch connected between the node and ground. The controller is configured for controlling the high-voltage switches.

Transmitter with adjustable transmit level for magnetic link

The device for amplifying input signals (,) comprises a control stage (,) and a switching bridge amplifier (,), which is coupled to said control stage via at least first and second control signals (,). The bridge amplifier (,) can be switched in at least two states, in dependence upon the control signals (,). The control stage (,) is embodied so as to control only a single substantially passive state of the bridge amplifier (,), as a result of which relatively small switching losses occur.

Device for amplifying signals

A battery charger comprising a converter (CNV) for converting an input voltage (U,) which is connected between an input terminal (,) and a reference terminal (GND) into a terminal voltage (V,) of a rechargeable battery (BT) which is connected between an output terminal (,) and the reference terminal (GND). The converter comprises a first and a second switch (SW,, SW,), a coil (L), a control circuit (CNTRL), a comparator (CMP), a frequency counter (CNT), and an indicator (IND). If the terminal voltage (V,) is lower than the reference voltage (V,), the start signal (ST) delivered by the comparator (CMP) will turn logic high. As a consequence the control circuit (CNTRL) will start an energy transfer cycle for transferring an amount of energy from the input terminal (,) to the rechargeable battery (BT). The frequency of the start signal (ST) decreases as the terminal voltage (V,) increases. By measuring the frequency of the start signal (ST) the indicator (IND) has the possibility of supplying a battery-high indication signal (BTHGH) when the rechargeable battery (BT) is almost full.

Battery charger

A converter for converting a terminal voltage (V,) supplied by a battery (BT) which is connected between an input terminal (,) and a reference terminal (GND) into an output voltage (U,) across a load (Z,) which is connected between an output terminal (,) and the reference terminal (GND). The converter comprises a first and a second switch (SW,, SW,), a coil (L), a control circuit (CNTRL), a comparator (CMP), a frequency counter (CNT), and an indicator (IND). If the output voltage (U,) is lower than the reference voltage (V,), the start signal (ST) will turn logic high. As a consequence the control circuit (CNTRL) will start an energy transfer cycle for transferring an amount of energy from the battery (BT) to the load (Z,). The frequency of the start signal (ST) increases as the terminal voltage (V,) decreases. By measuring the frequency of the start signal (ST), the indicator (IND) has the possibility of supplying a battery-low indication signal (BTLW) when the battery (BT) is almost empty.

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Eindhoven, Netherlands

Harry Neuteboom