Abstract: A capacitance-to-digital-converter includes a first delay block configured to output a first signal after a first delay based on a voltage at a capacitive sensor, the capacitive sensor configured to be iteratively discharged; a second delay block configured to output a second signal after a second delay; and a capacitance determination unit configured to determine a value indicative of a capacitance sensed by the capacitive sensor. This determination is based on: a number of clock periods during which the first delay is less than a third delay; a first time difference between receipt of the first signal and the second signal during a last clock period during which the first delay is less than the third delay; and a second time difference between receipt of the first signal and receipt of the second signal during a first clock period during which the first delay is greater than the third delay.

Abstract: A capacitance-to-digital-converter includes a first delay block configured to output a first signal after a first delay based on a voltage at a capacitive sensor, the capacitive sensor configured to be iteratively discharged; a second delay block configured to output a second signal after a second delay; and a capacitance determination unit configured to determine a value indicative of a capacitance sensed by the capacitive sensor. This determination is based on: a number of clock periods during which the first delay is less than a third delay; a first time difference between receipt of the first signal and the second signal during a last clock period during which the first delay is less than the third delay; and a second time difference between receipt of the first signal and receipt of the second signal during a first clock period during which the first delay is greater than the third delay.

Abstract: One example discloses a ratiometric device, including: a current source having a first current, a second current different from the first current, and a current-select program; a sensor device responsive to a gas and having a sensor-cold temperature T(cold,sens) in response to the first current and a sensor-hot temperature T(hot,sens) in response to the second current; a reference device having a reference-cold temperature T(cold,ref) in response to the first current and a reference-hot temperature T(hot,ref) in response to the second current; and wherein the ratiometric device includes a temperature difference ratio output based on T(cold,sens), T(hot,sens), T(cold,ref) and T(hot,ref).

Abstract: A leadless cardiac pacemaker comprises a hermetic housing, a power source disposed in the housing, at least two electrodes supported by the housing, a semiconductor temperature sensor disposed in the housing, and a controller disposed in the housing and configured to deliver energy from the power source to the electrodes to stimulate the heart based upon temperature information from the temperature sensor. In some embodiments, the sensor can be configured to sense temperature information within a predetermined range of less than 20 degrees C. The temperature sensor can be disposed in the housing but not bonded to the housing.

Abstract: One example discloses a ratiometric device, including: a current source having a first current, a second current different from the first current, and a current-select program; a sensor device responsive to a gas and having a sensor-cold temperature T(cold,sens) in response to the first current and a sensor-hot temperature T(hot,sens) in response to the second current; a reference device having a reference-cold temperature T(cold,ref) in response to the first current and a reference-hot temperature T(hot,ref) in response to the second current; and wherein the ratiometric device includes a temperature difference ratio output based on T(cold,sens), T(hot,sens), T(cold,ref) and T(hot,ref).

Abstract: A leadless cardiac pacemaker comprises a hermetic housing, a power source disposed in the housing, at least two electrodes supported by the housing, a semiconductor temperature sensor disposed in the housing, and a controller disposed in the housing and configured to deliver energy from the power source to the electrodes to stimulate the heart based upon temperature information from the temperature sensor. In some embodiments, the sensor can be configured to sense temperature information within a predetermined range of less than 20 degrees C. The temperature sensor can be disposed in the housing but not bonded to the housing.

Abstract: A leadless cardiac pacemaker comprises a hermetic housing, a power source disposed in the housing, at least two electrodes supported by the housing, a semiconductor temperature sensor disposed in the housing, and a controller disposed in the housing and configured to deliver energy from the power source to the electrodes to stimulate the heart based upon temperature information from the temperature sensor. In some embodiments, the sensor can be configured to sense temperature information within a predetermined range of less than 20 degrees C. The temperature sensor can be disposed in the housing but not bonded to the housing.

Abstract: A leadless cardiac pacemaker comprises a hermetic housing, a power source disposed in the housing, at least two electrodes supported by the housing, a semiconductor temperature sensor disposed in the housing, and a controller disposed in the housing and configured to deliver energy from the power source to the electrodes to stimulate the heart based upon temperature information from the temperature sensor. In some embodiments, the sensor can be configured to sense temperature information within a predetermined range of less than 20 degrees C. The temperature sensor can be disposed in the housing but not bonded to the housing.

Abstract: A system is disclosed that includes an oven and a micromechanical oscillator inside the oven configured to oscillate at a predetermined frequency at a predetermined temperature, where the predetermined frequency is based on a temperature dependency and at least one predetermined property. The system further includes an excitation mechanism configured to excite the micromechanical oscillator to oscillate at the predetermined frequency and a temperature control loop configured to detect a temperature of the micromechanical oscillator using resistive sensing, determine whether the temperature of the micromechanical oscillator is within a predetermined range of the predetermined temperature based on the temperature dependency and the at least one predetermined property in order to minimize frequency drift, and adapt the temperature of the micromechanical oscillator to remain within the predetermined range.

Abstract: An embodiment is directed to an instrumentation amplifier. The instrumentation amplifier includes an output stage for generating an output voltage, a low-frequency path coupled with the output stage, and a high-frequency path coupled with the output stage. The high-frequency path dominates the low-frequency path at frequencies above a particular frequency, and the low-frequency path dominates the high-frequency path at frequencies below the particular frequency. The low-frequency path includes an input stage for sensing a differential input and generating an intermediate current based thereon, a feedback stage coupled with the input and output stages, the feedback stage for generating a feedback current based on the output voltage, and an auto-zeroing circuit coupled with the input, feedback, and output stages, the auto-zeroing circuit for generating a nulling current.

Abstract: A method for calibrating a digital temperature sensor circuit, the circuit comprising an analogue temperature sensing means, an internal reference voltage source and an analogue-to-digital converter (ADC). The ADC is arranged to receive respective signals from the analogue temperature sensing means and the reference voltage source and output a digital signal indicative of the ambient temperature. The method comprises the steps of determining the value of the internal reference voltage outputted by the reference voltage source, comparing it with the desired reference voltage value, and adjusting the reference voltage source in response to the result of the comparison step. Such an electrical voltage mode calibration can significantly reduce production costs, as it can be performed much faster than a traditional thermal calibration. The method can be applied to a sensor that produces a PTAT voltage that has to be compared to a temperature-independent bandgap reference voltage.

Abstract: An embodiment of the present invention is directed to an instrumentation amplifier. The amplifier includes a first amplification sub-circuit, which includes an input stage for sensing a differential input and generating an intermediate current based thereon, a feedback stage, and an auto-zeroing circuit. The feedback stage is operable to generate a feedback current based on an output voltage of the amplifier. The auto-zeroing circuit is operable to generate a nulling current, which compensates for errors in the intermediate and feedback currents resulting from input offsets in the input and feedback stages. The amplifier further includes a second amplification sub-circuit, an output stage, and a switching circuit. The switching circuit switches the amplifier between first and second configurations. In the first configuration, the first amplification sub-circuit provides a first amplification path for the amplifier.

Abstract: An embodiment is directed to an instrumentation amplifier. The instrumentation amplifier includes an output stage for generating an output voltage, a low-frequency path coupled with the output stage, and a high-frequency path coupled with the output stage. The high-frequency path dominates the low-frequency path at frequencies above a particular frequency, and the low-frequency path dominates the high-frequency path at frequencies below the particular frequency. The low-frequency path includes an input stage for sensing a differential input and generating an intermediate current based thereon, a feedback stage coupled with the input and output stages, the feedback stage for generating a feedback current based on the output voltage, and an auto-zeroing circuit coupled with the input, feedback, and output stages, the auto-zeroing circuit for generating a nulling current.

Abstract: A bias circuit for use in bandgap voltage reference circuits and temperature sensors comprises a pair of transistors (Q, Q2), the first of which (Q1) is arranged to be biased at an emitter current lbias, and the second of which (Q2) is arranged to be biased at an emitter current of m.lbias. The circuit is arranged such that the difference between the base-emitter voltages of the transistors is generated in part across a first resistance means having a value Rbias and in use carrying a bias current equal to lbias and in part across a second resistance means of value substantially equal to Rbias/m and in use carrying a current equal to the base current of the second transistor. This results in use in a bias current Ibias which, when used to bias a substrate bipolar transistor via its emitter, produces a collector current therefrom which is substantially PTAT and a base-emitter voltage which is substantially independent of the forward current gain of the substrate bipolar transistor.

Abstract: A bias circuit for use in bandgap voltage reference circuits and temperature sensors comprises a pair of transistors (Q, Q2), the first of which (Q1) is arranged to be biased at an emitter current lbias, and the second of which (Q2) is arranged to be biased at an emitter current of m.lbias. The circuit is arranged such that the difference between the base-emitter voltages of the transistors is generated in part across a first resistance means having a value Rbias and in use carrying a bias current equal to lbias and in part across a second resistance means of value substantially equal to Rbias/m and in use carrying a current equal to the base current of the second transistor. This results in use in a bias current Ibias which, when used to bias a substrate bipolar transistor via its emitter, produces a collector current therefrom which is substantially PTAT and a base-emitter voltage which is substantially independent of the forward current gain of the substrate bipolar transistor.

Abstract: A method for calibrating a digital temperature sensor circuit, the circuit comprising an analogue temperature sensing means, an internal reference voltage source and an analogue-to-digital converter (ADC). The ADC is arranged to receive respective signals from the analogue temperature sensing means and the reference voltage source and output a digital signal indicative of the ambient temperature. The method comprises the steps of determining the value of the internal reference voltage outputted by the reference voltage source, comparing it with the desired reference voltage value, and adjusting the reference voltage source in response to the result of the comparison step. Such an electrical voltage mode calibration can significantly reduce production costs, as it can be performed much faster than a traditional thermal calibration. The method can be applied to a sensor that produces a PTAT voltage that has to be compared to a temperature-independent bandgap reference voltage.

Abstract: When a reference signal is generated for a digital-to-analog converter in the feedback path of a sigma-delta modulator, the reference signal can contain modulated error signals, for example when the reference generator implements dynamic element matching. By controlling the reference signal generation in dependence on the bitstream output from the sigma-delta modulator, the effects of intermodulation of the reference signal with the bitstream can be reduced.