Drive device, ultrasonic sensor and vehicle

1 . A drive device, comprising:

a burst generating circuit, configured to generate a burst signal, wherein the burst signal comprises a plurality of first pulses transmitted consecutively and a plurality of second pulses transmitted consecutively, wherein plurality of first pulses and the plurality of second pulses have different frequencies; and

a drive circuit, configured to

generate a pulse drive signal based on the burst signal and

supply the pulse drive signal to a target-driving element, wherein

the pulse drive signal includes a first signal, corresponding to the plurality of first pulses, having a self-wave identification frequency and a second signal, corresponding to the plurality of second pulses, having a frequency other than the self-wave identification frequency.

2 . The drive device of claim 1 , wherein

the drive circuit is configured to, when the frequency of the pulse drive signal is switched from a first frequency to a second frequency higher than the first frequency, switch from the first frequency to the second frequency after passing through a third frequency higher than the second frequency, and

the frequency of the second signal is the third frequency.

3 . The drive device of claim 1 , wherein

the drive circuit is configured to, when the frequency of the pulse drive signal is switched from a fourth frequency to a fifth frequency lower than the fourth frequency, switch from the fourth frequency to the fifth frequency after passing through a sixth frequency lower than the fifth frequency, and

the frequency of the second signal is the sixth frequency.

4 . The drive device of claim 1 , wherein the drive circuit is configured to

set a preliminary drive period for the target-driving element before a drive period of the target-driving element and

render the frequency of the pulse drive signal at a beginning of the drive period to be different from the frequency of the pulse drive signal during the preliminary drive period, wherein

the frequency of the second signal is the frequency of the pulse drive signal during the preliminary drive period.

5 . The drive device of claim 1 , wherein a number of pulses of the second signal is less than a number of pulses of the first signal.

6 . The drive device of claim 1 , further comprising a power supply circuit, wherein

the drive circuit uses a voltage supplied from the power supply circuit as a power supply voltage, and

the burst generating circuit is configured to vary a duty of the burst signal according to at least one of a temporal position of a drive period of the target-driving element and a frequency of the burst signal.

7 . The drive device of claim 6 , wherein the burst generating circuit is configured to

vary the duty according to the temporal position, and

render the duty when the temporal position is a first position, to be smaller than the duty when the temporal position is a second position subsequent to the first position.

8 . The drive device of claim 6 , wherein the burst generating circuit is configured to

vary the duty according to the frequency of the burst signal, wherein the duty when the frequency of the burst signal is a seventh frequency, is made to be smaller than the duty when the frequency of the burst signal is an eighth frequency, wherein

an impedance of the target-driving element, when the frequency of the burst signal is the seventh frequency, is less than an impedance of the target-driving element when the frequency of the burst signal is the eighth frequency.

9 . An ultrasonic sensor, comprising:

a piezoelectric element; and

the drive device of claim 1 , configured to drive the piezoelectric element.

10 . A vehicle, comprising the ultrasonic sensor of claim 9 .