Methods and circuitry for built-in self-testing of circuitry and/or transducers in ultrasound devices
Aspects of the technology described herein relate to built-in self-testing (BIST) of circuitry (e.g., a pulser or receive circuitry) and/or transducers in an ultrasound device. A BIST circuit may include a transconductance amplifier coupled between a pulser and receive circuitry, a capacitor network coupled between a pulser and receive circuitry, and/or a current source couplable to the input terminal of receive circuitry to which a transducer is also couplable. The collapse voltages of transducers may be characterized using BIST circuitry, and a bias voltage may be applied to the membranes of the transducers based at least in part on their collapse voltages. The capacitances of transducers may also be measured using BIST circuitry and a notification may be generated based on the sets of measurements.
1. An ultrasound device operable in testing and imaging modes, the ultrasound device comprising:
a pulser configured to generate voltage pulses;
receive circuitry;
a capacitive micromachined ultrasonic transducer (CMUT) couplable to the receive circuitry; and
a built-in self-test (BIST) circuit including a transconductance amplifier coupled between the pulser and the receive circuitry,
wherein during the testing mode, the transconductance amplifier is turned on and is configured to convert the voltage pulses to a current signal and the receive circuitry is configured to convert to current signal to a voltage signal for verifying operation of the pulser, and
wherein during the imaging mode, the transconductance amplifier is turned off and the voltage pulses are provided to the CMUT to output ultrasonic waves.
2. The ultrasound device according to claim 1 , wherein the transconductance amplifier includes a linearized transconductance amplifier.
3. The ultrasound device according to claim 1 , wherein the transconductance amplifier includes a source-degenerated linearized transconductance amplifier.
4. The ultrasound device according to claim 1 , further comprising a resistor ladder, and wherein the transconductance amplifier and the pulser are configured to receive, as input signals, voltages from the resistor ladder.
5. The ultrasound device according to claim 1 , wherein the transconductance amplifier is coupled between the pulser and a circuit in the receive circuitry configurable as a transimpedance amplifier.
6. The ultrasound device according to claim 5 , wherein the transimpedance amplifier is configured to convert the current signal to a low-voltage signal.
7. The ultrasound device according to claim 1 , wherein the transconductance amplifier is coupled between the pulser and a circuit in the receive circuitry configurable as a comparator.
8. The ultrasound device according to claim 1 , wherein the transconductance amplifier is coupled between the pulser and a circuit in the receive circuitry configurable as a delta-sigma analog-to-digital converter.
9. The ultrasound device of claim 1 , wherein:
the pulser is configured to use a first power supply;
the transconductance amplifier is configured to use a second power supply;
the receive circuitry is configured to use a third power supply; and
the first power supply has a higher voltage than the second power supply and the second power supply has a higher voltage than the third power supply.
10. The ultrasound device of claim 1 , wherein during the imaging mode, the pulser and the receive circuitry remain on.
11. The ultrasound device of claim 1 , wherein the pulser, the receive circuitry, the CMUT, and the transconductance amplifier are disposed within a single package.
12. The ultrasound device of claim 1 , wherein BIST circuit is disposed on a same semiconductor chip as the pulser, the receive circuitry, and/or the CMUT.