Pop and click noise reduction

• US 9,225,293 B2
• Filed: 07/03/2012
• Issued: 12/29/2015
• Est. Priority Date: 07/10/2011
• Status: Active Grant

• Current Assignee: Triune Systems, LLC (Semtech Corporation)
• Original Assignee: Triune Systems, LLC (Semtech Corporation)
• Inventors: Teggatz, Ross E., Chen, Wayne T., Smith, Brett
• Primary Examiner(s): Sing, Simon
• Application Number:
  US13/540,920
• Publication Number:
  US 20130028441A1
• Time in Patent Office: 1,274 Days
• Field of Search: 381/94.5
• US Class Current: 1/1
• CPC Class Codes: H03F 1/305 in case of switching on or off of a power supply
• CPC Class Codes: H03F 2200/03 the amplifier being designed for audio applications
• CPC Class Codes: H03F 3/181 Low-frequency amplifiers, e.g. audio preamplifiers
• CPC Class Codes: H03F 3/2173 of the bridge type
• CPC Class Codes: H03K 17/687 the devices being field-effect transistors
• CPC Class Codes: H03K 5/1252 Suppression or limitation of noise or interference specially adapted for transmission systems H04B15/00, H04L25/08
• CPC Class Codes: H04R 3/007 Protection circuits for transducers

Abstract

Disclosed are advances in the arts with novel and useful electronic circuitry with pop and click noise reduction. A load circuit is connected with a full or single-ended half-H bridge circuit and another circuit mechanism in a configuration by which a signal may be used to selectably bring the load circuit terminals to a selected voltage level when an externally applied signal is not present.

Claims

1. An electronic circuit comprising:

a load circuit having a load element and first and second terminals, the terminals each further comprising a capacitor;

a bridge circuit having an output node operably coupled with the first load terminal and a feedback node operably coupled with the second load terminal;

an op amp operably coupled to receive an input signal and to supply an output signal to the feedback node;

wherein the op amp output signal is configured to bring the terminals of the load circuit to a selected voltage level; and

wherein the op amp receives a feedback input from a load circuit terminal and turns off when the voltage level at the load circuit is not zero.

2. The electronic circuit of claim 1 wherein the op amp receives feedback input from a load terminal and turns off when the load receives a signal at the output node of the bridge circuit.

3. The electronic circuit of claim 1 wherein the bridge circuit further comprises a single-ended half-H bridge circuit.

4. The electronic circuit of claim 1 wherein the op amp receives feedback input from the output node.

5. The electronic circuit of claim 1 wherein the op amp receives feedback input from the feedback node.

6. The electronic circuit of claim 1, wherein the selected voltage level the op amp is used to bring the terminals of the load circuit to, consists of a mid-rail level.

7. The electronic circuit of claim 1 further comprising a wave-shape circuit operably coupled for providing an input signal to the op amp.

8. The electronic circuit of claim 1 further comprising a wave-shape circuit operably coupled for providing an input signal to the op amp, the wave-shape circuit further comprising an RC network.

9. The electronic circuit of claim 1 further comprising a wave-shape circuit operably coupled for providing an input signal to the op amp, the wave-shape circuit further comprising a digital-to-analog converter controllable to output a specific voltage signal shape.

10. An electronic circuit comprising:

a load circuit having a load element and first and second terminals, the terminals each further comprising a capacitor;

a bridge circuit having an output node operably coupled with the first load circuit terminal and a feedback node operably coupled with the second load circuit terminal;

an op amp operably coupled to receive an input signal and to supply an output signal to the output node;

wherein the op amp output signal is configured to bring the terminals of the load circuit to a selected voltage level; and

wherein the op amp receives a feedback input from a load terminal and turns off when the voltage level at the load circuit is not zero.

11. The electronic circuit of claim 10 wherein the op amp receives feedback input from a load terminal and turns off when the load circuit receives a signal at the output node of the bridge circuit.

12. The electronic circuit of claim 10 wherein the op amp receives feedback input from the output node.

13. The electronic circuit of claim 10 wherein the op amp receives feedback input from the feedback node.

14. The electronic circuit of claim 10, wherein the selected voltage level the op amp is used to bring the terminals of the load circuit to, consists of a mid-rail level.

15. The electronic circuit of claim 10 further comprising a wave-shape circuit operably coupled for providing an input signal to the op amp.

16. The electronic circuit of claim 10 further comprising a wave-shape circuit operably coupled for providing an input signal to the op amp, the wave-shape circuit further comprising an RC network.

17. The electronic circuit of claim 10 further comprising a wave-shape circuit operably coupled for providing an input signal to the op amp, the wave-shape circuit further comprising a digital-to-analog converter controllable to output a specific voltage signal shape.

18. The electronic circuit of claim 10 wherein the load circuit further comprises a speaker element.

19. An electronic circuit comprising:

a load circuit having a load and first and second terminals, the terminals each further comprising a capacitor;

a bridge circuit having an output node operably coupled with the first load terminal and a feedback node operably coupled with the second load terminal;

a first op amp operably coupled to receive an input signal and to supply an output signal to the bridge circuit feedback node and to supply the same output signal as a input signal to a second op amp coupled for providing an output signal to the bridge circuit output node;

wherein the respective op amp output signals is configured to bring the terminals of the load to a selected voltage level without transiting the load;

wherein the first op amp receives a feedback input from the bridge circuit feedback node and turns off when the voltage level at the node is not zero

and the second op amp receives a feedback input from the output node and turns off when the voltage level at the node is not zero.

20. The electronic circuit of claim 19 wherein the op amp receives feedback input from a load terminal and turns off when the load receives a signal at the output node of the bridge circuit.

21. The electronic circuit of claim 19, wherein the selected voltage level the first and second op amps are used to bring the terminals of the load to, consists of a mid-rail level.

22. The electronic circuit of claim 19 further comprising a wave-shape circuit operably coupled for providing an input signal to the first op amp.

23. The electronic circuit of claim 19 further comprising a wave-shape circuit operably coupled for providing an input signal to the first op amp, the wave-shape circuit further comprising an RC network.

24. The electronic circuit of claim 19 further comprising a wave-shape circuit operably coupled for providing an input signal to the op amp, the wave-shape circuit further comprising a digital-to-analog converter controllable to output a specific voltage signal shape.

25. An electronic circuit comprising:

a load circuit having a load and first and second terminals, the terminals each further comprising a capacitor;

a single-ended half-H bridge circuit having an output node operably coupled with the first load terminal and a feedback node operably coupled with the second load terminal;

a selector circuit having an output to the bridge circuit, and a first input operably coupled to receive an electronic signal, and a second input operably coupled to receive a signal from a wave-shape circuit;

wherein the selector circuit is configured for selecting either the audio signal or the wave-shape signal for transmittal to the output node;

whereby the wave-shape signal is applied to the output node in the absence of an output signal.

26. The electronic circuit of claim 25 wherein the wave-shape signal is applied for bringing the load terminals to a mid-rail voltage level.

27. An electronic circuit comprising:

a load circuit having a load and first and second terminals, the terminals each further comprising a capacitor;

a bridge circuit having an output node operably coupled with the first load terminal and a feedback node operably coupled with the second load terminal;

a selector circuit having an output to the bridge circuit, and a first input operably coupled to receive an audio signal, and a second input operably coupled to receive a signal from a wave-shape circuit;

an op amp operably coupled to receive an input signal from the wave-shape circuit and to supply an output signal to the feedback node;

wherein the selector circuit is configured for selecting either the audio signal or the wave-shape signal for transmittal to the output node;

whereby the wave-shape signal is applied to the output node and the feedback node of the bridge circuit in the absence of an output signal.

28. The electronic circuit of claim 27 wherein the wave-shape signal is applied for bringing the load terminals to a mid-rail voltage level.

29. The electronic circuit of claim 27 wherein the bridge circuit further comprises an H-bridge circuit.