# US 2017/0285155 A1 · Multilevel bipolar pulser > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0285155 A1 - Document ID: US20170285155A1 - Status: Published application - Kind: A1 - Application number: 15/087,914 - Filed: 2016-03-31 - Published: 2017-10-05 - Earliest claimed: 2016-03-31 - Assignees: Butterfly Network, Inc. - Applicants: Butterfly Network, Inc. - Inventors: Kailiang Chen; Tyler S. Ralston; Keith G. Fife - Web page: https://patentgrep.com/patent/US20170285155A1 ## CPC - G01S 7/52022: {using a sequence of pulses, at least one pulse manipulating the transmissivity or reflexivity of the medium} - G01S 7/52017: {particularly adapted to short-range imaging (G01S7/53 takes precedence)} - G01S 7/5202: {for pulse systems} - G01S 7/52047: {for elimination of side lobes or of grating lobes; for increasing resolving power} - G01S 7/5205: {Means for monitoring or calibrating} - G01S 7/5208: {with integration of processing functions inside probe or scanhead} - G01S 7/521: Constructional features - G01S 15/8915: {using a transducer array} - G01S 15/8977: {using special techniques for image reconstruction, e.g. FFT, geometrical transformations, spatial deconvolution, time deconvolution} - A61B 7/04: Electric stethoscopes - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract Circuitry for ultrasound devices is described. A multilevel pulser is described, which can provide bipolar pulses of multiple levels. The multilevel pulser includes a pulsing circuit and pulser and feedback circuit. Symmetric switches are also described. The symmetric switches can be positioned as inputs to ultrasound receiving circuitry to block signals from the receiving circuitry. ## Claims ### Claim 1 An apparatus, comprising: a complementary metal oxide semiconductor (CMOS) die having ultrasonic transducers and an integrated circuit formed thereon, wherein the integrated circuit comprises a pulser with feedback. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the pulser is a multi-level pulser configured to generate at least three voltage levels. ### Claim 3 An ultrasound device comprising: at least one capacitive ultrasonic transducer; a pulser having an input terminal and an output terminal, the pulser coupled, at the output terminal, to the capacitive ultrasonic transducer and configured to provide an input signal to the capacitive ultrasonic transducer; and a feedback circuit coupled to the output terminal and the input terminal of the pulser and configured to provide a control signal to the input terminal of the pulser based on a comparison of a detection signal, representing or derived from the input signal, to a threshold voltage. ### Claim 4 (depends on 3) The ultrasound device according to claim 3, wherein the pulser is configured to provide a bipolar input signal to the capacitive ultrasonic transducer. ### Claim 5 (depends on 3) The ultrasound device according to claim 3, wherein the pulser is configured to provide the input signal having a value selected from among multiple selectable values. ### Claim 6 (depends on 5) The ultrasound device according to claim 5, wherein the pulser is configured to provide the input signal having a direct current (DC) component that is greater than zero. ### Claim 7 (depends on 5) The ultrasound device according to claim 5, wherein the feedback circuit is configured to provide the control signal to the input terminal of the pulser based on a comparison of the detection signal to a first threshold voltage of a plurality of threshold voltages generated by the feedback circuit. ### Claim 8 (depends on 7) The ultrasound device according to claim 7, wherein the feedback circuit comprises a resistive ladder configured to generate the plurality of threshold voltages. ### Claim 9 (depends on 3) The ultrasound device according to claim 3, wherein the feedback circuit is configured to control the control signal to temporally apodize the input signal. ### Claim 10 (depends on 3) The ultrasound device according to claim 3, wherein the feedback circuit is digitally controlled. ### Claim 11 (depends on 3) The ultrasound device according to claim 3, wherein the feedback circuit is configured to provide the control signal to the pulser asynchronously. ### Claim 12 (depends on 3) The ultrasound device according to claim 3, where the capacitive ultrasonic transducer is a first capacitive ultrasonic transducer of a plurality of capacitive ultrasonic transducers, the pulser is a first pulser of a plurality of pulsers, the feedback circuit is a first feedback circuit of a plurality of feedback circuits, the control signal is a first control signal of a plurality of control signals and the input signal is a first input signal of a plurality of input signals; wherein the plurality of feedback circuits are configured to control the plurality of control signals to spatially apodize the plurality of input signals provided to the plurality of capacitive ultrasonic transducers. ### Claim 13 (depends on 3) The ultrasound device according to claim 3, wherein the capacitive ultrasonic transducer is coupled to bias circuitry and configured to receive a bias voltage having an absolute value that is greater than zero. ### Claim 14 (depends on 3) The ultrasound device according to claim 3, wherein the pulser comprises a first transistor exhibiting a first type of conductivity and a second transistor exhibiting a second type of conductivity different from the first type of conductivity. ### Claim 15 (depends on 3) The ultrasound device according to claim 3, further comprising a dividing circuit configured to provide the detection signal to the feedback circuit, wherein the detection signal is proportional to the input signal. ### Claim 16 A method of operating an ultrasound device having a capacitive ultrasonic transducer, a pulser coupled to the capacitive ultrasonic transducer, and a feedback circuit, the method comprising: with the pulser, providing an input signal to the capacitive ultrasonic transducer ; deriving a detection signal from the input signal, the detection signal representing the input signal; and with the feedback circuit, providing a control signal to the pulser to control the provision of the input signal based on a result obtained by comparing the detection signal to a threshold voltage. ### Claim 17 (depends on 16) The method of operating an ultrasound device according to claim 16, wherein the pulser is configured to provide a bipolar input signal to the capacitive ultrasonic transducer. ### Claim 18 (depends on 16) The method of operating an ultrasound device according to claim 16, wherein the pulser is configured to provide the input signal having a value selected from among multiple selectable values. ### Claim 19 (depends on 16) The method of operating an ultrasound device according to claim 16, wherein the pulser is configured to provide the input signal having a direct current (DC) component that is greater than zero. ### Claim 20 (depends on 16) The method of operating an ultrasound device according to claim 16, wherein the feedback circuit is configured to control the control signal to temporally apodize the input signal. ### Claim 21 (depends on 16) The method of operating an ultrasound device according to claim 16, wherein providing the control signal to the pulser to control the providing of the input signal is performed asynchronously. ### Claim 22 (depends on 16) The method of operating an ultrasound device according to claim 16, wherein the feedback circuit is digitally controlled. ### Claim 23 (depends on 16) The method of operating an ultrasound device according to claim 16, wherein the capacitive ultrasonic transducer is a first capacitive ultrasonic transducer of a plurality of capacitive ultrasonic transducers, the pulser is a first pulser of a plurality of pulsers, the feedback circuit is a first feedback circuit of a plurality of feedback circuits, the control signal is a first control signal of a plurality of control signals and the input signal is a first input signal of a plurality of input signals; wherein the plurality of feedback circuits are configured to control the plurality of control signals to spatially apodize the plurality of input signals provided to the plurality of capacitive ultrasonic transducers.