Abstract: The present disclosure relates to an integrated circuit with at least a first channel and a second channel. Each channel includes at least a DAC. The integrated circuit also includes a number of circuit elements interconnected between the channels. The circuit elements can be changed between a short circuit state and an open circuit state. Normally, each channel will operate independently of one another, using only the circuit components in its respective channel. However, the circuit elements are arranged to allow a user to combine part of the second channel with the first channel to improve the functionality and performance of the first channel. In particular, a state of the circuit elements can be chosen to combine components of the second channel with the first channel. For example, components (e.g. a sub-stage) of the second channel can be connected in parallel with corresponding components (e.g. a corresponding sub-stage) of the first channel.

Abstract: The present disclosure relates to a digital-to-analog converter comprising an impedance network and a transfer function modification circuit. The transfer function modification circuit comprises a DAC and a demultiplexer. The demultiplexer may be used to selectively connect the output of the DAC to different respective nodes of the impedance network, allowing positive or negative currents to be injected into the node and modify the transfer function. By using a demultiplexer to selectively couple to different nodes, the node into which the current is injected may be modified post-manufacture, allowing transfer function modification.

Abstract: A source stochastic signal is deconstructed into one or more components using a decomposition process. The decomposition process deconstructs the source stochastic signal into at least one component which encodes the oscillatory behavior of the source stochastic signal. The one or more components are mapped, using one or more trained models, to a pair of target components which encode the estimated oscillatory behavior and estimated steady-state behavior of a target stochastic signal. The target stochastic signal is then reconstructed from the oscillatory behavior target signal by shifting the oscillatory behavior target signal so that its average value aligns with the average value of the steady-state behavior target signal. The source stochastic signal and the target stochastic signals can be biological signals having a related or common origin, such as photoplethysmogram (PPG) signals and arterial blood pressure (ABP) waveforms.

Abstract: A digital technique to reduce or minimize switching in a DAC by using a partial DAC data ignore switching mode. In the partial DAC data ignore switching mode, a control circuit compares first and second data, such a first and second digital words, and operates corresponding switches only when the first data differ from the second data. The techniques are applicable to many types of DACs, including voltage output DACs, current output DACs, variable resistance DACs, digital rheostats, digital potentiometers, digiPOTs.

Abstract: A digital technique to reduce or minimize switching in a DAC by using a partial DAC data ignore switching mode. In the partial DAC data ignore switching mode, a control circuit compares first and second data, such a first and second digital words, and operates corresponding switches only when the first data differ from the second data. The techniques are applicable to many types of DACs, including voltage output DACs, current output DACs, variable resistance DACs, digital rheostats, digital potentiometers, digiPOTs.

Abstract: The present disclosure relates to a field effect transistor (FET) structure. The FET structure has a substrate, an active region, a dielectric layer provided over a channel of the active region and a gate provided over the dielectric layer. The active region comprises a source, a drain and the channel provided between the source and the drain. The active region is surrounded by an isolation trench, such that width edges of the channel are directly adjacent to the isolation trench. Current paths run between the source and the drain, through the channel. The FET is configured such that current paths running proximal to the channel edges are reduced or weaker in comparison to a dominant current path running through a center of the channel. One or more of the channel, the dielectric layer or the substrate can be modified or adapted to provide the reduced and dominant current paths.

Abstract: A method of feedback control of an amplifier system includes driving multiple amplifier circuits using at least one digital-to-analog converter (DAC) circuit to set a system output of the amplifier system, operating the at least one DAC circuit using a first set of DAC codes to set the system output to a steady state target output, detecting a high glitch transition of the first set of DAC codes that is greater than a specified threshold transition, and changing to operating the at least one DAC circuit using a second set of DAC codes to set the system output to substantially the same steady state target output, wherein operating the at least one DAC circuit using the second set of DAC codes reduces glitch energy at the output of the at least one DAC circuit.

Abstract: A circuit supply system includes a main digital to analog converter (DAC) circuit to produce a direct current (DC) output level at a system output; a feedback circuit path connected to the system output; a primary control circuit path connected to the feedback circuit path and configured to regulate the DC output level at the system output using the main DAC circuit and the feedback circuit path; and a secondary control circuit path connected to the feedback circuit path and configured to add a non-DC signal component to the DC output level and regulate the non-DC signal component using the feedback circuit path.

Abstract: The present disclosure relates to an integrated circuit with at least a first channel and a second channel. Each channel includes at least a DAC. The integrated circuit also includes a number of circuit elements interconnected between the channels. The circuit elements can be changed between a short circuit state and an open circuit state. Normally, each channel will operate independently of one another, using only the circuit components in its respective channel. However, the circuit elements are arranged to allow a user to combine part of the second channel with the first channel to improve the functionality and performance of the first channel. In particular, a state of the circuit elements can be chosen to combine components of the second channel with the first channel. For example, components (e.g. a sub-stage) of the second channel can be connected in parallel with corresponding components (e.g. a corresponding sub-stage) of the first channel.

Abstract: The present disclosure relates to a configurable output stage for a DAC channel. The output stage receives an analog output from a DAC and outputs a signal to an output terminal. The output stage is configurable between a voltage mode and a current mode. In the voltage mode, the output stage supplies the analog signal to the output terminal as a voltage signal. In the current mode, the output stage supplies the analog signal to the output signal as a current signal. The output stage can receive user input to select the desired mode. Consequently, an integrated circuit can be implemented with multiple DAC channels, each having the configurable output stage. A user can choose how many channels they want to operate in a voltage output mode, and how many channels they want to operate in a current output mode, depending on their individual requirements.

Abstract: Techniques for generating a diagnostic waveform for a sensor are provided. In an example, a control circuit for an electrochemical sensor can include power supply inputs configured to receive a supply voltage, a first signal generator configured to receive control information and to generate a first signal on a first output using the supply voltage and the control information, a second signal generator configured to receive the control information and to provide a second signal on a second output, using the supply voltage and the control information. An output voltage between the first output and the second output, in a diagnostic mode of operation of the control circuit, can include a periodic signal having a peak-to-peak voltage greater than the supply voltage.

Abstract: A closed loop switch control system and a corresponding method is provided for controlling an impedance of a switch. The switch, which usually comprises a transistor switch, may be part of an external circuit. The system comprises the switch and a control unit coupled to the switch. The control unit is configured to regulate an impedance of the switch to a reference impedance while also enabling a fast switch response time. This is achieved by configuring the control unit to have a frequency response comprising a plurality of dominant poles and at least one zero.

Abstract: The present disclosure relates to a field effect transistor (FET) structure. The FET structure has a substrate, an active region, a dielectric layer provided over a channel of the active region and a gate provided over the dielectric layer. The active region comprises a source, a drain and the channel provided between the source and the drain. The active region is surrounded by an isolation trench, such that width edges of the channel are directly adjacent to the isolation trench. Current paths run between the source and the drain, through the channel. The FET is configured such that current paths running proximal to the channel edges are reduced or weaker in comparison to a dominant current path running through a center of the channel. One or more of the channel, the dielectric layer or the substrate can be modified or adapted to provide the reduced and dominant current paths.

Abstract: A closed loop switch control system and a corresponding method is provided for controlling an impedance of a switch. The switch, which usually comprises a transistor switch, may be part of an external circuit. The system comprises the switch and a control unit coupled to the switch. The control unit is configured to regulate an impedance of the switch to a reference impedance while also enabling a fast switch response time. This is achieved by configuring the control unit to have a frequency response comprising a plurality of dominant poles and at least one zero.

Abstract: Techniques for generating a diagnostic waveform for a sensor are provided. In an example, a control circuit for an electrochemical sensor can include power supply inputs configured to receive a supply voltage, a first signal generator configured to receive control information and to generate a first signal on a first output using the supply voltage and the control information, a second signal generator configured to receive the control information and to provide a second signal on a second output, using the supply voltage and the control information. An output voltage between the first output and the second output, in a diagnostic mode of operation of the control circuit, can include a periodic signal having a peak-to-peak voltage greater than the supply voltage.

Abstract: Techniques for generating a diagnostic waveform for a sensor are provided. In an example, a control circuit for an electrochemical sensor can include power supply inputs configured to receive a supply voltage, a first signal generator configured to receive control information and to generate a first signal on a first output using the supply voltage and the control information, a second signal generator configured to receive the control information and to provide a second signal on a second output, using the supply voltage and the control information. An output voltage between the first output and the second output, in a diagnostic mode of operation of the control circuit, can include a periodic signal having a peak-to-peak voltage greater than the supply voltage.

Abstract: The present disclosure relates to a digital-to-analog converter (DAC) which includes a resistor string and a transfer function modification circuit. The transfer function modification circuit may be a calibration circuit for calibrating the DAC, The calibration circuit may include a plurality of current sources, which may be current DACs. Each of the current DACS inject current into, or drain current from, a respective node of the resistor string, in order to correct for voltage errors. The injected currents may be positive or negative, depending on the voltage error. The current DACs are controlled by trim codes, which are set dependent on the measured or simulated voltage errors for a given resistor string.

Abstract: A control circuit for use with a four terminal sensor, the sensor having first and second drive terminals and first and second measurement terminals, the control circuit arranged to drive at least one of the first and second drive terminals with an excitation signal, to sense a voltage difference between the first and second measurement terminals, and control the excitation signal such that the voltage difference between the first and second measurement terminals is within a target range of voltages, and wherein the control circuit includes N poles in its transfer characteristic and N?1 zeros in its transfer characteristic such that when a loop gain falls to unity the phase shift around a closed loop is not substantially 2? radians or a multiple thereof, where N is greater than 1.

Abstract: The present disclosure relates to a digital-to-analog converter (DAC) which includes a resistor string and a transfer function modification circuit. The transfer function modification circuit may be a calibration circuit for calibrating the DAC, The calibration circuit may include a plurality of current sources, which may be current DACs. Each of the current DACS inject current into, or drain current from, a respective node of the resistor string, in order to correct for voltage errors. The injected currents may be positive or negative, depending on the voltage error. The current DACs are controlled by trim codes, which are set dependent on the measured or simulated voltage errors for a given resistor string.

Abstract: Many electronic circuits rely on the ratio of one component to other components being well defined. Current flow in component can warm the component causing its electrical properties to change, for example the resistance of a resistor may increase due to self-heating as a result of current flow. The present disclosure provides a way to reduce temperature variation between components so as to reduce electrical mismatch between them or the consequences of such mismatch. This is important as even a change of resistance of, for example, 20-50 ppm in a resistor can result in non-linearity exceeding the least significant bit value of a 16 bit digital to analog converter.