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: 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: An illustrative controller includes: a transmitter to drive the acoustic transducer to generate a series of acoustic bursts; a receiver coupled to the acoustic transducer to sense a response for each acoustic burst in the series; and a processing circuit to derive output data from said responses in part by determining a difference between one of the responses and at least a portion of another one of the responses. Another illustrative controller includes: a transmitter to drive the acoustic transducer to generate a series of acoustic bursts with signature sequence of frequency displacements; a receiver coupled to the acoustic transducer to sense a response for each acoustic burst in the series; and a processing circuit to derive output data from said responses in part by suppressing any peaks not conforming to the signature sequence.

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: Accordingly, there is disclosed herein host device and bus communication method that enables fast sensor device reinitialization that minimizes outage time associated with an unexpected device reset. One illustrative bus communication method includes: providing each of one or more slave devices with a dynamically-determined bus address; querying each of the dynamically-determined bus addresses to obtain a unique device identifier associated with that dynamically-determined bus address; receiving a sequence of data frames each having time-division multiplexed data from the one or more slave devices; and between data frames in the sequence, checking to determine whether any of the one or more slave devices has been reset.

Abstract: An acoustic distance measurement circuit includes a transmitter, a receiver, and a controller. The transmitter has an output adapted to be coupled to an acoustic transducer for providing a selected one of an amplitude-modulation (AM) signal in an AM mode and a chirp signal in a chirp mode. The receiver has an input adapted to be coupled to the acoustic transducer, and an output for providing a digital received signal. The controller is operative during a first measurement period to: place the transmitter into one of the AM mode and the chirp mode using a first channel, selectively detect a direct echo in the first channel of the digital received signal of the one of the AM signal and the chirp signal, and selectively detect an indirect echo in a second channel of the digital received signal of another one of the AM signal and the chirp signal.

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: 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: Secure serial bus communication methods and devices suitable for automotive applications. An illustrative sensor IC includes: a sensor controller that operates a transducer to obtain measurement data formattable as data packets; a scrambler that masks each data packet with a scrambling operation before that data block is sent via a serial bus to a bus controller device, said scrambling operation having a secret configuration and/or secret initial state; and an integrated circuit component that operates on a seed value to derive the secret configuration and/or secret initial state.

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: The various embodiments of the present disclosure are directed to devices, system and processes for detecting saturation of a received signal in a PAS system. A process may include detecting, in a received signal and during a measurement interval, one or more correlated signal levels. Based on one or more results of the detecting, the process may include identifying in a correlated output signal portions of the received signal which exceed a given magnitude threshold during the measurement interval and providing the correlated output signal to an electronic control unit (ECU). A magnitude detector outputs the correlated output signal. A saturation detector determines whether the received signal is saturated during a portion of a measurement interval. When the received signal is saturated, a saturation signal is generated and provided on a delayed basis to the ECU such that it is provided substantially contemporaneously with the correlated output signal.

Abstract: An illustrative controller includes: a transmitter to drive the acoustic transducer to generate acoustic bursts; a receiver to sense a response of the acoustic transducer to echoes; and a processing circuit coupled to the transmitter and to the receiver, the processing circuit configured to convert said received response into output data by: correlating said response to a driving signal to obtain a correlation response; distinguishing peak areas from non-peak areas in said correlation response; deriving a noise level in a portion of said correlation response based on the non-peak areas within said portion; calculating a signal to noise ratio (SNR) for a peak signal within the portion as a ratio of a peak value for the peak signal to the noise level in said portion of said correlation response; and accepting the peak signal as an echo only if the SNR for said peak signal exceeds a predetermined threshold.

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: An illustrative controller includes: a transmitter to drive the acoustic transducer to generate acoustic bursts; a receiver to sense a response of the acoustic transducer to echoes; and a processing circuit coupled to the transmitter and to the receiver, the processing circuit configured to convert said received response into output data by: correlating said response to a driving signal to obtain a correlation response; distinguishing peak areas from non-peak areas in said correlation response; deriving a noise level in a portion of said correlation response based on the non-peak areas within said portion; calculating a signal to noise ratio (SNR) for a peak signal within the portion as a ratio of a peak value for the peak signal to the noise level in said portion of said correlation response; and accepting the peak signal as an echo only if the SNR for said peak signal exceeds a predetermined threshold.

Abstract: An illustrative controller includes: a transmitter to drive the acoustic transducer to generate a series of acoustic bursts; a receiver coupled to the acoustic transducer to sense a response for each acoustic burst in the series; and a processing circuit to derive output data from said responses in part by determining a difference between one of the responses and at least a portion of another one of the responses. Another illustrative controller includes: a transmitter to drive the acoustic transducer to generate a series of acoustic bursts with signature sequence of frequency displacements; a receiver coupled to the acoustic transducer to sense a response for each acoustic burst in the series; and a processing circuit to derive output data from said responses in part by suppressing any peaks not conforming to the signature sequence.

Abstract: Sensors may employ a constant false alarm rate (CFAR) screening process in combination with edge-based echo detection. In one illustrative embodiment, a sensor controller includes: a transmitter, a receiver, and a processing circuit coupled to the transmitter and to the receiver. The transmitter drives a piezoelectric element to generate acoustic bursts. The receiver senses a response of the piezoelectric element to echoes of each acoustic burst. The processing circuit is operable to apply echo-detection processing to the response by: determining a derivative signal from the response; and detecting an echo based at least in part on a peak in the derivative signal indicating a rising and/or falling edge in the response. Signaling to the electronic control unit may specify a time of flight associated with each edge.