Temperature sensing

Patent metadata

Field	Value
Publication number	US-9924287-B2
Application number	US-201615209852-A
Country	US
Kind code	B2
Filing date	Jul 14, 2016
Priority date	Jul 24, 2015
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

A circuit and method for determining an ambient temperature for an electronic device having a loudspeaker are described. An amplifier drives the loudspeaker and first circuitry is configure to determine an overall temperature of the loudspeaker or the amplifier. Second circuitry is configured to determine a change in temperature of the loudspeaker or the amplifier resulting from power dissipated in the loudspeaker or the amplifier. Third circuitry is configured to subtract a signal representative of the change in temperature from a signal representative of the overall temperature and output a signal representative of the ambient temperature for the electronic device.

First claim

The invention claimed is:

1. A circuit for determining an ambient temperature for an electronic device having a loudspeaker, the circuit comprising:
an amplifier for driving configured to drive a loudspeaker;
first circuitry configured to
determine an overall temperature of the loudspeaker or the amplifier and
output a signal representative of the overall temperature of the loudspeaker or the amplifier;

second circuitry configured to
determine a change in temperature of the loudspeaker or the amplifier resulting from power dissipated in the loudspeaker or the amplifier and
output a signal representative of the change in temperature of the loudspeaker or the amplifier; and

third circuitry configured to
subtract the signal representative of the change in temperature from the signal representative of the overall temperature and
output a signal representative of the ambient temperature for the electronic device based on the subtraction.

2. The circuit as claimed in claim 1 , wherein said second circuitry includes a thermal model of the loudspeaker or the amplifier.

3. The circuit as claimed in any of claims 2 , wherein the thermal model depends at least on the power dissipated by the loudspeaker or the power dissipated by the amplifier.

4. The circuit as claimed in claim 1 and further comprising
a first input in communication with an input of the amplifier and arranged to receive an audio signal to be amplified by the amplifier and
a second input arranged to receive a reference signal having a frequency less than a fundamental resonant frequency of a voice coil of the loudspeaker.

5. The circuit as claimed in claim 1 , wherein said first circuitry includes circuitry configured to determine the DC resistance of a loudspeaker coil and circuitry configured to determine the overall temperature of the loudspeaker based on the DC resistance of the loudspeaker coil.

6. The circuit as claimed in claim 1 , where said first circuitry includes a temperature sensor in thermal communication with the amplifier.

7. The circuit as claimed in claim 6 , wherein said second circuitry is in communication with an input of the amplifier and is arranged to receive a signal indicative of the power of an audio signal to be amplified by the amplifier.

8. A package comprising a lead frame and a semiconductor integrated circuit, wherein the semiconductor integrated circuit comprises the circuit of claim 1 .

9. The package as claimed in claim 8 , wherein the package is a smart amplifier.

10. The circuit of claim 1 , wherein the circuit for determining an ambient temperature is included in a mobile electronic device.

11. The circuit of claim 10 , wherein the mobile electronic device is a mobile telephone.

12. A circuit for determining an ambient temperature for an electronic device having a loudspeaker, the circuit comprising:
an amplifier for driving a loudspeaker;
first circuitry configured to
determine an overall temperature of the loudspeaker or the amplifier and
output a signal representative of the overall temperature of the loudspeaker or the amplifier;

second circuitry configured to
determine a change in temperature of the loudspeaker or the amplifier resulting from power dissipated in the loudspeaker or the amplifier and
output a signal representative of the change in temperature of the loudspeaker or the amplifier;

third circuitry configured to subtract the signal representative of the change in temperature from the signal representative of the overall temperature and output a signal representative of the ambient temperature for the electronic device;
a first input in communication with an input of the amplifier and arranged to receive an audio signal to be amplified by the amplifier; and
a second input arranged to receive a reference signal having a frequency less than a fundamental resonant frequency of a voice coil of the loudspeaker.

13. A circuit for determining an ambient temperature for an electronic device having a loudspeaker, the circuit comprising:
an amplifier configured to drive a loudspeaker;
first circuitry configured to
determine an overall temperature of the loudspeaker or the amplifier and
output a signal representative of the overall temperature of the loudspeaker or the amplifier;

second circuitry configured to
determine a change in temperature of the loudspeaker or the amplifier resulting from power dissipated in the loudspeaker or the amplifier and
output a signal representative of the change in temperature of the loudspeaker or the amplifier; and

third circuitry configured to
subtract the signal representative of the change in temperature from the signal representative of the overall temperature and
output a signal representative of the ambient temperature for the electronic device based on the subtraction;

wherein the amplifier is configured to receive an audio signal and a reference signal; and
wherein the circuit for determining the ambient temperature is configured to measure the ambient temperature while the reference signal is driving the loudspeaker.

Assignees

• Nxp Bv

Inventors

• Macours Christophe
• Huijser Jan Paulus Freerk
• Scarlett Shawn

Classifications

• G01K7/16

  using resistive elements · CPC title

• H03F2200/468

  the temperature being sensed · CPC title

• H04R2201/028

  Structural combinations of loudspeakers with built-in power amplifiers, e.g. in the same acoustic enclosure (H04R2499/10 takes precedence; Single (sub)woofer with two or more satellite loudspeakers for mid- and high-frequency band reproduction driven via the (sub)woofer H04R2205/026) · CPC title

• H03F3/181

  Low-frequency amplifiers, e.g. audio preamplifiers · CPC title

• H03F1/30

  Modifications of amplifiers to reduce influence of variations of temperature or supply voltage {or other physical parameters (in differential amplifiers H03F3/45479)} · CPC title