Abstract: Various sensors, sensor controllers, and sensing methods are suitable for use in a multi-channel ultrasonic sensor array such as those used in systems for parking assistance, blind spot monitoring, and driver assistance. One illustrative acoustic sensing method includes: driving an acoustic transducer to send acoustic bursts each including an up-chirp in a first frequency band and a down-chirp in a second frequency band; receiving echo signals responsive to the acoustic bursts from the transducer; and using the echo signals to determine a distance or time of flight from the transducer. Another acoustic sensing method includes: driving an acoustic transducer to send acoustic bursts each including a concurrent up-chirp and down-chirp; receiving echo signals responsive to the acoustic bursts from the transducer; and using the echo signals to determine a distance or time of flight from the transducer.

Abstract: In one form, an acoustic distance measuring circuit includes a frequency generator, a transmitter amplifier, an acoustic transducer, and a sensing circuit. The sensing circuit includes an input adapted to be coupled to the acoustic transducer, for receiving an input signal. The sensing circuit provides an in-phase portion and a quadrature portion of the input signal to a filter. The sensing circuit filters the in-phase portion and the quadrature portion and calculates a phase of the input signal in response to the filtered in-phase and quadrature portions. The sensing circuit determines a frequency slope of the input signal in response to calculating the phase and provides the frequency slope of the input signal to an output.

Abstract: A sensor device coupled to a communication interface bus, the sensor device includes: a current source having a first terminal operable to receive a supply current, a second terminal operable to provide a supply current, and a control terminal, wherein an operating voltage is supplied by a current through the current source; a voltage clamp having a first terminal coupled to the second terminal of the current source, a second terminal coupled to a power supply terminal, and an output terminal operable to provide a current sense signal; and a control circuit having an input terminal coupled to the output terminal of the voltage clamp and an output terminal coupled to the control terminal of the current source operable to provide an adjustment signal responsive to the current sense signal, wherein the current source is configured to adjust the current through the current source responsive to the adjustment signal.

Abstract: Embodiments include a primary short circuit coupled to a primary side of a transformer and a dampening element, coupled to a transducer coupled to a secondary side of the transformer, configured to dampen a received signal during a portion of a reverberation period.

Abstract: Embodiments include a primary short circuit (PSC) coupled to a primary side of a transformer and a dampening element, coupled to a transducer coupled to a secondary side of the transformer, configured to dampen a received signal during a portion of a reverberation period. The PSC and the dampening element may be activated substantially simultaneously. Activation of the PSC circuit mitigates a parallel resonance otherwise arising, in part, in the transducer, but, increases the received signal by a DC shift voltage. The dampening element dampens the DC shift voltage. The received signal may be dampened prior to amplification of the received signal by an amplifier. The dampening facilitates earlier and more precise measurement, during the reverberation period, of at least one operating characteristic for the PAS sensor. Another embodiment prevents the DC shift voltage by selectively activating the PSC within a determined time of a zero-crossing of a given signal.

Abstract: One implementation of a sensing method includes: correlating a receive signal with a waveform template to obtain a correlation signal in which echoes would be represented as peaks; and varying the waveform template based on time elapsed from a measurement start time.

Abstract: A sensor device coupled to a communication interface bus, the sensor device enters a low power mode in which some operations of the sensor device are suspended when the sensor device receives insufficient power over the bus, thereby significantly reducing the likelihood that digital components of the sensor device will need to be reset due to an under-voltage condition.

Abstract: Embodiments include devices, system and processes for facilitating ultra-short range detection of obstacles using a PAS sensor. A process may include obtaining a correlation of at least two characteristics of a transducer; determining a given transmission frequency and selecting a reverberation time desired for the transducer; obtaining a damping ratio corresponding to the selected reverberation time; generating a ranging signal command; generating a damping signal command; and outputting each of the ranging signal command and the damping signal command. The ranging signal command may instruct a PAS sensor to drive the transducer to output a ranging signal at the given transmission frequency, at a transmission amplitude, and at a transmission phase and the damping signal command results in a dampening, at the damping ratio, of transducer reverberations arising from the ranging signal. The damping ratio may be between thirty percent (30%) and eighty percent (80%) of the transmission amplitude.

Abstract: One implementation of a sensing method includes: correlating a receive signal with a waveform template to obtain a correlation signal in which echoes would be represented as peaks; and varying the waveform template based on time elapsed from a measurement start time.

Abstract: Methods and devices provide for enhanced robustness via graceful packet error detection and packet retransmission. One illustrative sensing method includes: generating a voltage pulse on a signal conductor coupled to a sensor array including one or more active sensors, the voltage pulse representing a broadcast read command (BRC) that defines a frame of one or more time-division-multiple-access (TDMA) slots, one slot for each active sensor to send a data packet; performing current sensing on the signal conductor to receive the data packet from each of the one or more active sensors; determining whether each said data packet is received error free; and requesting retransmission of each said data packet not received error free.

Abstract: One implementation of a sensing method includes: correlating a receive signal with a first channel waveform template to obtain a first channel correlation signal in which first channel echoes would be represented as peaks; correlating the receive signal with a second channel waveform template to obtain a second channel correlation signal in which second channel echoes would be represented as peaks; and varying the first channel waveform template and the second channel waveform template based on time elapsed from a measurement start time. A sensor array implementation includes: multiple acoustic transducers that operate concurrently to send acoustic bursts in different frequency channels, each of the multiple acoustic transducers configured to use the foregoing method.

Abstract: Disclosed sensors, sensor controllers, and sensor control methods enhance transducer performance using a model-based equalization method that can be performed in the field. One illustrative method for operating a piezoelectric-based sensor includes: sensing a response of a piezoelectric transducer as a function of frequency; deriving parameter values of an equivalent circuit for the piezoelectric transducer from the response; using a squared magnitude of the equivalent circuit's transfer function to determine a system level selectivity; and adapting at least one operating parameter of the sensor based on the system level selectivity. One illustrative controller for a piezoelectric transducer includes: a transmitter that drives the piezoelectric transducer; a receiver that senses a response of the piezoelectric transducer; and a processing circuit coupled to the transmitter and to the receiver to calibrate the transducer using the foregoing method.

Abstract: Piezoelectric sensor controllers may facilitate detection and identification of various potential fault states with parameter measurements. In an illustrative embodiment of a piezoelectric-based sensor having response-parameter-based fault diagnosis, the sensor includes a piezoelectric transducer and a controller. The controller drives the piezoelectric transducer to generate bursts of acoustic energy and, based on a response of the piezoelectric transducer to said driving, identifies a corresponding transducer state from a set of potential states including multiple transducer fault states.

Abstract: Piezoelectric sensor controllers may facilitate detection and identification of various potential fault states including noise-induced sensor blindness. In one illustrative embodiment, a sensor controller includes: a transmitter to drive a piezoelectric element during actuation intervals to generate acoustic bursts; a receiver to sense a response of the piezoelectric element to echoes of each acoustic burst, the receiver including a front-end amplifier; a processing circuit coupled to the transmitter and to the receiver, the processing circuit operable to apply echo-detection processing to said response; and a blindness detector to detect saturation of the front-end amplifier during or prior to the measurement intervals.

Abstract: A sensor device coupled to a communication interface bus, the sensor device includes: a current source having a first terminal operable to receive a supply current, a second terminal operable to provide a supply current, and a control terminal, wherein an operating voltage is supplied by a current through the current source; a voltage clamp having a first terminal coupled to the second terminal of the current source, a second terminal coupled to a power supply terminal, and an output terminal operable to provide a current sense signal; and a control circuit having an input terminal coupled to the output terminal of the voltage clamp and an output terminal coupled to the control terminal of the current source operable to provide an adjustment signal responsive to the current sense signal, wherein the current source is configured to adjust the current through the current source responsive to the adjustment signal.

Abstract: A sensor device coupled to a communication interface bus, the sensor device enters a low power mode in which some operations of the sensor device are suspended when the sensor device receives insufficient power over the bus, thereby significantly reducing the likelihood that digital components of the sensor device will need to be reset due to an under-voltage condition.

Abstract: Piezoelectric sensor controllers may facilitate detection and identification of various potential fault states with novel parameter measurements. In an illustrative embodiment of a piezoelectric-based sensor having a shorted-reverberation based resonant frequency measurement, the sensor includes a piezoelectric transducer that provides residual reverberation after being driven. The sensor further includes a controller that provides a low impedance path for the piezoelectric transducer during the residual reverberation and that measures current through the low impedance path to determine a resonant frequency of the piezoelectric transducer.

Abstract: One implementation of a sensing method includes: correlating a receive signal with a first channel waveform template to obtain a first channel correlation signal in which first channel echoes would be represented as peaks; correlating the receive signal with a second channel waveform template to obtain a second channel correlation signal in which second channel echoes would be represented as peaks; and varying the first channel waveform template and the second channel waveform template based on time elapsed from a measurement start time. A sensor array implementation includes: multiple acoustic transducers that operate concurrently to send acoustic bursts in different frequency channels, each of the multiple acoustic transducers configured to use the foregoing method.

Abstract: Various sensors, sensor controllers, and sensor control methods are provided with model-based sideband balancing. In one illustrative embodiment, a controller for a piezoelectric transducer includes a transmitter, a receiver, and a processing circuit coupled to the transmitter and receiver. The processing circuit performs calibration and echo detection, the calibration including: sensing the piezoelectric transducer's phase response as a function of frequency; deriving equivalent circuit parameters for the piezoelectric transducer from the phase response; and determining a sideband imbalance based on one or more of the equivalent circuit parameters. Once the sideband imbalance is identified, the processing circuit may perform echo-detection processing that accounts for the sideband imbalance.

Abstract: In one form, a method for acoustic distance measurement includes generating an acoustic signal with an acoustic transducer at a first time. A pulse is detected with the acoustic transducer in response to the acoustic signal encountering an obstacle within a predetermined distance. Detecting the pulse includes detecting a second time relative to the first time when a magnitude of the pulse rises above a predetermined threshold, and detecting a peak magnitude of the pulse. A correction ratio is determined as a ratio of the predetermined threshold to the peak magnitude of the pulse. A correction time is determined in response to the correction ratio. A corrected time-of-flight is determined by adjusting the second time by the compensation time.