Pulse generator for energizing an ultrasonic transducer, a method of operating the pulse generator and a ultrasonic distance sensing system

Patent metadata

Field	Value
Publication number	US-2016284967-A1
Application number	US-201514666883-A
Country	US
Kind code	A1
Filing date	Mar 24, 2015
Priority date	Mar 24, 2015
Publication date	Sep 29, 2016
Grant date	—

Abstract

The present application relates to a pulse generator for energizing an ultrasonic transducer, a method of operating thereof and an ultrasonic distance sensing system comprising the pulse generator. The pulse generator is arranged to generate an excitation pulse sequence comprising a first number of pulses; to generate a cancellation pulse sequence comprising at least a fractional pulse, wherein the cancellation pulse sequence has a phase shift of about 180° in relation to the excitation pulse sequence; and to output at an output of the generator the excitation pulse sequence and the cancellation pulse sequence forming an energizing pulse sequence to the ultrasonic transducer.

First claim

1 . A pulse generator for energizing an ultrasonic transducer, wherein the pulse generator is arranged to
generate an excitation pulse sequence comprising a first number of pulses; generate a cancellation pulse sequence comprising at least a fractional pulse, wherein the cancellation pulse sequence has a phase shift of about 180° in relation to the excitation pulse sequence; and provide at an output of the pulse generator the excitation pulse sequence and the cancellation pulse sequence forming an energizing pulse sequence for energizing the ultrasonic transducer.

2 . The pulse generator according to claim 1 , further comprising:
wherein the cancellation pulse sequence comprising a second number of pulses followed by the fractional pulse.

3 . The pulse generator according to claim 1 , further comprising:
a clock generator supplying a clock signal, wherein the clock signal is a common reference for determining the duration of the pulse; and a configurable controller coupled to the clock generator for receiving the clock signal and arranged to generate the excitation and cancellation pulse sequences.

4 . The pulse generator according to claim 3 ,
wherein the configurable controller is arranged to accept configuration parameters including an excitation sequence length relating to the first number of pulses and a fractional duration relating to the length of the fractional pulse.

5 . The pulse generator according to claim 4 ,
wherein the configuration parameters further include a cancellation sequence length relating to the second number of pulses.

6 . The pulse generator according to claim 4 ,
wherein the configuration parameters further comprises a predefined first period of time and a predefined second period of time, wherein the predefined first period of time relates to a duration, during which a generated pulse of the energizing pulse sequence is at a first level, wherein the predefined second period of time relates to a duration, during which a generated pulse of the energizing pulse sequence is at a second level.

7 . The pulse generator according to claim 1 , further comprising:
wherein the pulses of the excitation and cancellation sequences are square pulses with a configurable duty cycle.

8 . The pulse generator according to claim 1 , further comprising:
wherein the pulse generator is part of a transmitter circuit for energizing the ultrasonic transducer.

9 . An ultrasonic distance sensing system comprising:
an ultrasonic transducer; and a pulse generator as claimed in claim 1 , wherein the pulse generator is arranged to generate an energizing pulse sequence for energizing ultrasonic transducer.

10 . The ultrasonic distance sensing system according to claim 9 , further comprising:
a transmission circuit comprising four transistors in an H-bridge arrangement, wherein the gates of the transistors are each coupled to the pulse generator and are pairwise switched conducive on the basis of the energizing pulse sequence output by the pulse generator.

11 . A method of energizing an ultrasonic transducer, said method comprising:
generating an excitation pulse sequence comprising a first number of pulses; generating a cancellation pulse sequence comprising at least a fractional pulse, wherein the cancellation pulse sequence has a phase shift of about 180° in relation to the excitation pulse sequence; and outputting the excitation pulse sequence and the cancellation pulse sequence forming an energizing pulse sequence to the ultrasonic transducer, wherein the ultrasonic transducer is energized in accordance with the energizing pulse sequence.

12 . The method according to claim 11 ,
wherein the energizing pulse sequence is applied to the ultrasonic transducer arranged in an H-bridge arrangement to control a current flow in alternating directions through the ultrasonic transducer.

13 . The method according to claim 11 ,
wherein the cancellation pulse sequence further comprises a second number of pulses, wherein the generating of the cancellation pulse sequence comprises: generating a pulse sequence comprising the second number of pulses; and immediately afterwards generating the factional pulse.

14 . The method according to claim 11 ,
wherein the excitation pulse sequence is an excitation square pulse sequence.

15 . The method according to claim 11 ,
wherein the cancellation pulse sequence is a cancellation square pulse sequence.

16 . The method according to claim 11 ,
wherein the generating the excitation pulse sequence further comprises generating one or more pulses at an output by driving the output at a first level for a first predetermined period of time; and driving the output at a second level for a second predetermined period of time, wherein the energizing pulse sequence is provide at the output.

17 . The method according to claim 16 ,
wherein the generating of the fraction pulse of the cancellation pulse sequence further comprises at least one of: driving an output at the second level for a third predetermined period of time, wherein the third predetermined period of time is shorter than the second predetermined period of time; and driving the output at a second level for a second period of time and driving the output at the first level for a third predetermined period of time, wherein the third predetermined period of time is shorter than the first predetermined period of time.

18 . The method according to claim 16 ,
wherein the generating of the cancellation pulse sequence further comprises generating one or more pulses at the output by driving the output at the second level for the first predetermined period of time; and driving the output at a first level for the second predetermined period of time.

19 . The pulse generator according to claim 2 , further comprising:
a clock generator supplying a clock signal, wherein the clock signal is a common reference for determining the duration of the pulse; and a configurable controller coupled to the clock generator for receiving the clock signal and arranged to generate the excitation and cancellation pulse sequences.

20 . The method according to claim 17 ,
wherein the generating of the cancellation pulse sequence further comprises generating one or more pulses at the output by driving the output at the second level for the first predetermined period of time; and driving the output at a first level for the second predetermined period of time.

Assignees

• Freescale Semiconductor Inc

Inventors

• Kruecken Josef Maria Joachim
• Laudenbach Andreas

Classifications

• H01L41/042 Primary

  Electricity · mapped topic

• G01S15/10

  using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurement G01S15/32) · CPC title

• G01S15/931

  of land vehicles · CPC title

• G01S7/524 Primary

  Transmitters · CPC title

• H10N30/802 Primary

  Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits · CPC title