Methods and apparatuses for driving audio and ultrasonic signals from the same transducer

Patent metadata

Field	Value
Publication number	US-11856366-B2
Application number	US-202017079578-A
Country	US
Kind code	B2
Filing date	Oct 26, 2020
Priority date	Dec 6, 2016
Publication date	Dec 26, 2023
Grant date	Dec 26, 2023

Abstract

Driver circuitry is disclosed for driving an electroacoustic transducer to provide an output comprising both ultrasonic and audio signal components. The driver circuitry comprises an adjustment module configured to reduce the level of said ultrasonic component signal in response to an increase in an operational variable indicative of a level of said audio signal component, while also increasing the pulse duration, duty cycle, repetition frequency or frequency span or bandwidth of the ultrasonic component.

First claim

The invention claimed is:

1. Driver circuitry, configurable to provide an output signal comprising an ultrasonic signal component and an audio signal component, the driver circuitry comprising:
an ultrasonic signal generator for generating the ultrasonic signal component;
wherein at least two different parameters of the ultrasonic signal component are dependent on a level of the audio signal component.

2. Driver circuitry as claimed in claim 1 , wherein one of the at least two different parameters of the ultrasonic signal component is inversely dependent on the level of the audio signal component.

3. Driver circuitry as claimed in claim 1 , wherein one of the at least two different parameters of the ultrasonic signal component is an amplitude of the ultrasonic signal component.

4. Driver circuitry as claimed in claim 3 , wherein another of the at least two parameters of the ultrasonic signal component is a bandwidth, pulse duration, duty cycle or repetition rate of the ultrasonic signal component.

5. Driver circuitry as claimed in claim 3 wherein said ultrasonic signal generation module is configured to control the amplitude of said ultrasonic signal component by applying a controlled gain to said ultrasonic input signal.

6. Driver circuitry as claimed in claim 1 , wherein said ultrasonic signal generator is configured to generate an ultrasonic source signal and to generate the ultrasonic component signal by altering an amplitude of the ultrasonic source signal.

7. Driver circuitry as claimed in claim 6 , wherein the ultrasonic signal generator is configured to generate the ultrasonic source signal from a stored waveform.

8. Driver circuitry as claimed in claim 7 , wherein the stored waveform comprises the waveform of a signal burst.

9. Driver circuitry as claimed in claim 7 , wherein the ultrasonic signal generator is configured to generate the stored waveform on re-initialization, and store it for subsequent use.

10. Driver circuitry as claimed in claim 7 , wherein the ultrasonic signal generator is configured to generate the stored waveform based on a random bit sequence.

11. Driver circuitry as claimed in claim 1 , wherein said ultrasonic signal generator is configured to generate the ultrasonic component with a required amplitude, and with a required pulse duration, duty cycle, repetition frequency and frequency span or bandwidth.

12. Driver circuitry as claimed in claim 11 , wherein said ultrasonic signal generator is configured to generate the ultrasonic component signal by selecting from a plurality of stored waveforms corresponding to a set of respective required characteristics.

13. Driver circuitry as claimed in claim 11 , wherein said ultrasonic signal generator comprises a first waveform generator and a second waveform generator, and wherein the ultrasonic signal generator is configured to generate the ultrasonic component as an output either of the first waveform generator or of the second waveform generator, based on the level of the audio signal component.

14. Driver circuitry as claimed in claim 13 , wherein the first waveform generator is configured for generating a waveform of a first type and the second waveform generator is configured for generating a waveform of a second type, wherein the second type of waveform is simpler than the first type, and wherein the ultrasonic signal generator is configured to generate the ultrasonic component as an output of the first waveform generator when the level of said audio signal component is above a threshold level.

15. Driver circuitry as claimed in claim 14 , wherein the waveform of the first type is a wideband noise-like waveform.

16. Driver circuitry as claimed in claim 15 , wherein the first waveform generator comprises:
a digital noise generator, for generating a noise sequence of values;
a band-pass filter, for receiving the noise sequence and limiting the bandwidth thereof to an ultrasonic range; and
a window for selecting a set of samples output from the band-pass filter, corresponding to a required pulse duration.

17. Driver circuitry as claimed in claim 16 , wherein the digital noise generator comprises a pseudo-random bit sequence generator, for generating a random sequence of values with a flat wideband frequency spectrum.

18. An electronic device comprising driver circuitry as claimed in claim 1 , wherein the electronic device is at least one of: a portable device; a battery powered device; a communications device; a computing device; a mobile telephone; a laptop, notebook or tablet computer; a personal media player; a gaming device; and a wearable device.

19. Driver circuitry, configurable to provide an output signal comprising an ultrasonic signal component and an audio signal component, the driver circuitry comprising:
an ultrasonic signal generator for generating the ultrasonic signal component;
wherein a plurality of different parameters of the ultrasonic signal component are dependent on a parameter of the audio signal component.

20. Driver circuitry for providing an output signal comprising an ultrasonic signal component and an audio signal component, wherein the driver circuitry is configured to:
receive an audio source signal comprising an audio band signal component;
receive an ultrasonic source signal;
adjust the ultrasonic source signal based on the audio source signal to generate the ultrasonic signal component of the output signal; and
combine the audio source signal with the ultrasonic signal component to generate the output signal,
wherein adjusting the ultrasonic source signal comprises varying two or more different parameters of the ultrasonic source signal based on the audio source signal.

Assignees

• Cirrus Logic Int Semiconductor Ltd
• Cirrus Logic Inc

Inventors

• Lesso John Paul
• Andrieu Cedric
• Cuthill Calum

Classifications

• H04R23/00 Primary

  Transducers other than those covered by groups H04R9/00 - H04R21/00 {(diaphragms for transducers of the distributed-mode type H04R7/045)} · CPC title

• G01S7/52004

  Means for monitoring or calibrating (short-range imaging G01S7/5205) · CPC title

• G01S7/524

  Transmitters · CPC title

• G01S15/10

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

• H03G3/005

  Control by a pilot signal (H03G3/001 takes precedence) · CPC title