Embedded speaker protection for automotive audio power amplifier

Patent metadata

Field	Value
Publication number	US-9532142-B2
Application number	US-201615158854-A
Country	US
Kind code	B2
Filing date	May 19, 2016
Priority date	Dec 30, 2011
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

A digital circuit can be used in a speaker system. An intermediate node provides a speaker protection control signal. A first latch for receives an offset control signal. A first logic gate receives a play control signal, the offset control signal, and the speaker protection control signal. A second logic gate is coupled to the first latch for receiving the play control signal and the speaker protection control signal. A second latch is coupled to the first logic gate for providing a forced mute signal. A third latch is coupled to the second logic gate and to the intermediate node.

First claim

What is claimed is:

1. A digital circuit for use in a speaker system comprising:
an intermediate node for providing a speaker protection control signal;
a first latch for receiving an offset control signal;
a first logic gate for receiving a play control signal, the offset control signal, and the speaker protection control signal;
a second logic gate coupled to the first latch for receiving the play control signal and the speaker protection control signal;
a second latch coupled to the first logic gate for providing a forced mute signal; and
a third latch coupled to the second logic gate and to the intermediate node.

2. The digital circuit of claim 1 , wherein the first, second, and third latches are each controlled by a common amplifier control signal.

3. The digital circuit of claim 1 , wherein the first, second, and third latches each comprise a D-type flip flops.

4. The digital circuit of claim 3 , wherein each D-type flip flop comprises an inverted output coupled to a D input.

5. The digital circuit of claim 1 , wherein the first logic gate and the second logic gate each comprise a three-input NAND gate.

6. The digital circuit of claim 1 , wherein the first logic gate and the second logic gate each comprise a three-input AND gate.

7. The digital circuit of claim 1 , wherein the digital circuit is embedded in a power amplifier device.

8. A speaker system comprising the digital circuit of claim 1 , the system further comprising:
a speaker;
a power amplifier device coupled to the speaker, wherein the digital circuit is embedded in the power amplifier device; and
an offset comparator coupled to the speaker for providing the offset control signal.

9. An integrated circuit comprising:
a play control signal input node;
an offset indication input node;
a mute control output node;
an intermediate node;
a first latch with an input coupled to the offset indication input node;
a first comparison circuit with an output coupled to the mute control output node, the first comparison circuit having inputs coupled to the play control signal input node, the offset indication input node, and the intermediate node; and
a second comparison circuit with an output coupled to the intermediate node, the second comparison circuit having inputs coupled to the play control signal input node, an output of the first latch, and the intermediate node.

10. The integrated circuit of claim 9 , wherein integrated circuit is configured for use in a speaker system and wherein the intermediate node is configured to carry a speaker protection control signal.

11. The integrated circuit of claim 9 , wherein the first comparison circuit comprises a first logic gate and wherein the second comparison circuit comprises a second logic gate.

12. The integrated circuit of claim 11 , wherein the first comparison circuit further comprises a second latch coupled to an output of the first logic gate and wherein the second comparison circuit further comprises a third latch coupled to an output of the second logic gate.

13. The integrated circuit of claim 12 , wherein the first, second, and third latches are each controlled by a common amplifier control signal.

14. The integrated circuit of claim 13 , wherein the first, second, and third latches each comprise D-type flip flop.

15. The integrated circuit of claim 14 , wherein each D-type flip flop comprises an inverted output coupled to a D input.

16. The integrated circuit of claim 11 , wherein the first logic gate and the second logic gate each comprise a three-input NAND gate.

17. The integrated circuit of claim 9 , wherein the integrated circuit is embedded inside a power amplifier device.

18. A speaker system comprising the integrated circuit of claim 9 , the system further comprising:
a power amplifier device; and
an offset comparator coupled between the power amplifier device and an offset indication input node.

19. The system of claim 18 , further comprising a speaker with an input coupled to an output of the power amplifier device.

20. A digital circuit for controlling operation of a speaker system that includes a speaker coupled to an amplifier, the digital circuit comprising:
means for generating a speaker offset detection signal;
means for generating a speaker control signal based upon the speaker offset detection signal, a play control signal and an earlier value of the speaker control signal; and
means for generating a force mute signal based on the speaker offset detection signal, the play control signal and the generated speaker control signal.

Assignees

• Stmicroelectronics (Shenzhen) R&D Co Ltd
• St Microelectronics Srl
• St Microelectronics Srl

Inventors

• Li Xiangsheng
• Meroni Cristiano
• Yang Mei
• Xiong Xian Feng

Classifications

• H03F1/52

  Circuit arrangements for protecting such amplifiers {(monitoring arrangements G01R31/28; increasing reliability in communication systems, e.g. using redundancy H04B1/74)} · CPC title

• H03G3/348 Primary

  Muting in response to a mechanical action or to power supply variations, e.g. during tuning; Click removal circuits · CPC title

• H03F2200/321

  Use of a microprocessor in an amplifier circuit or its control circuit · CPC title

• H04R3/007 Primary

  Protection circuits for transducers · CPC title

• H03F2200/78

  A comparator being used in a controlling circuit of an amplifier · CPC title