Differential ultrasonic transducer element for ultrasound devices
Aspects of the technology described herein relate to ultrasound circuits that employ a differential ultrasonic transducer element, such as a differential micromachined ultrasonic transducer (MUT) element. The differential ultrasonic transducer element may be coupled to an integrated circuit that is configured to operate the differential ultrasonic transducer element in one or more modes of operation, such as a differential receive mode, a differential transmit mode, a single-ended receive mode, and a single-ended transmit mode.
1. An ultrasound circuit, comprising:
a differential micromachined ultrasonic transducer (MUT) element comprising a first MUT that is configured to be biased with a first bias voltage and a second MUT that is configured to be biased with a second bias voltage; and
an integrated circuit coupled to the differential MUT element and configured to operate the differential MUT element;
wherein the integrated circuit comprises a receive circuit that is configured to operate the differential MUT element to receive acoustic signals; and
wherein the receive circuit comprises a differential transimpedance amplifier (TIA) having a first input coupled to the first MUT, a second input coupled to the second MUT, a first output coupled to the first input by a first impedance, and a second output coupled to the second input by a second impedance.
2. The ultrasound circuit of claim 1 , wherein the first bias voltage is different from the second bias voltage.
3. The ultrasound circuit of claim 1 , wherein the integrated circuit comprises a transmit circuit that is configured to operate the differential MUT element to transmit acoustic signals.
4. The ultrasound circuit of claim 3 , wherein the transmit circuit comprises a differential pulser that is configured to generate a first pulse signal to drive the first MUT and a second pulse signal that has an opposite polarity of the first pulse signal that is configured to drive the second MUT.
5. The ultrasound circuit of claim 1 , wherein the receive circuit comprises a differential analog-to-digital converter having a first input coupled to the first output of the differential TIA and a second input coupled to the second output of the differential TIA.
6. The ultrasound circuit of claim 1 , wherein the receive circuit comprises a first switch coupled between the first input of the differential TIA and the first MUT and a second switch coupled between the second input of the differential TIA and the second MUT.
7. The ultrasound circuit of claim 1 , wherein the integrated circuit is configured to operate the differential MUT element in a plurality of modes comprising at least one mode selected from the group consisting of: a single-ended receive mode, a differential receive mode, a single-ended transmit mode, and a differential transmit mode.
8. An ultrasound circuit, comprising:
a differential micromachined ultrasonic transducer (MUT) element comprising a first MUT that is configured to be biased with a first bias voltage and a second MUT that is configured to be biased with a second bias voltage;
an integrated circuit coupled to the differential MUT element and configured to operate the differential MUT element; and
a third MUT that is biased with the first bias voltage and a fourth MUT that is biased with the second bias voltage.
9. The ultrasound circuit of claim 8 , wherein the first MUT and the third MUT are arranged in a first row of a 2 by 2 array and wherein the second MUT and the fourth MUT are arranged in a second row of the 2 by 2 array.
10. The ultrasound circuit of claim 8 , wherein the first MUT and the second MUT are arranged in a first row of a 2 by 2 array and wherein the third MUT and the fourth MUT are arranged in a second row of the 2 by 2 array.
11. A method of operating an ultrasound circuit comprising a differential micromachined ultrasonic transducer (MUT) element, the method comprising:
biasing the differential MUT element at least in part by biasing a first MUT of the differential MUT element with a first bias voltage and biasing a second MUT of the differential MUT element with a second bias voltage; and
operating the differential MUT element after biasing the differential MUT element;
wherein operating the differential MUT element comprises operating the differential MUT element to transmit acoustic signals at least in part by driving the first MUT with a first pulse signal and driving the second MUT with a second pulse signal that has an opposite polarity of the first pulse signal.
12. A method of operating an ultrasound circuit comprising a differential micromachined ultrasonic transducer (MUT) element, the method comprising:
biasing the differential MUT element at least in part by biasing a first MUT of the differential MUT element with a first bias voltage and biasing a second MUT of the differential MUT element with a second bias voltage; and
operating the differential MUT element after biasing the differential MUT element;
wherein operating the differential MUT element comprises operating the differential MUT element to receive acoustic signals at least in part by controlling a state of at least one switch to couple the first MUT to a first input of a differential transimpedance amplifier (TIA) and couple the second MUT to a second input of the differential TIA.
13. The method of claim 12 , wherein operating the differential MUT to receive acoustic signals comprises digitizing an output of an analog processing circuit that comprises the differential TIA using a differential analog-to-digital converter.