SPEAKER SYSTEM AND METHOD FOR ADJUSTING POWER OF SPEAKER

An exemplary speaker system includes a speaker, an audio amplifier, a detecting resistor, and a control unit. The audio amplifier is connected to the speaker and outputs a working voltage to the speaker. The detecting resistor is electronically connected between the speaker and the audio amplifier. The control unit is connected between the detecting resistor and the audio amplifier. The control unit detects a voltage of the detecting resistor, calculates a real-time power of the speaker, and compares the real-time power with a rated power of the speaker. When the real-time power equals to or exceeds the rated power, the control unit adjusts the working voltage until the real-time power is below the rated power.

DETAILED DESCRIPTION

FIG. 1is a block diagram of a speaker system100, according to an exemplary embodiment. The speaker system100can be used with or in an electronic device (not shown) assembled with a speaker. The electronic device may be a mobile phone or a personal digital assistant, for example.

The speaker system100includes an audio amplifier10, a speaker20, a detecting resistor30, a filter40, and a control unit50. The audio amplifier10is electronically connected to the speaker20and outputs a working voltage to the speaker20. In this embodiment, the voltage value provided by the audio amplifier20is Vo.

The speaker20is used to play audio files. The speaker20has a rated power and a working power corresponding to the working voltage provided by the audio amplifier10. Generally, when the working power of the speaker20is less than the rated power, the speaker20works normally. Once the working power equals to or is out of the rated power, the speaker20works abnormally and may be damaged.

One end of the detecting resistor30is electronically connected to the audio amplifier10. Another end of the detecting resistor30is electronically connected to the speaker20. In this way, the audio amplifier10, the speaker20, and the detecting resistor30form a current loop, and current flowing through the speaker20equals to current flowing through the detecting resistor30. Thus, current flowing through the speaker20can be detected by the detecting resistor30. A resistance of the detecting resistor30is Rext. In this embodiment, the resistance Rext is less than 1 ohm.

The filter40is electronically connected to the detecting resistor30in parallel. In this embodiment, the filter40is a low-pass filter. The filter40filters a high-frequency signal of the speaker system100, such as a D-type high-frequency signal, thereby obtaining a pure detecting voltage of the detecting resistor30.

The control unit50is electronically connected between the filter40and the audio amplifier10. The control unit50may be a central processing unit and includes an analog/digital (A/D) converter52, a calculating module54, and a control module56. The A/D converter52is electronically connected to the filter40. The A/D converter52receives a real-time detecting voltage Vext of the detecting resistor30, converts the detected voltage into a digital signal, and transmits the digital signal to the calculating module54. According to the detected voltage and the resistance of the detecting resistor30, the calculating module54calculates and obtains a real-time current Iext flowing through the detecting resistor30according to a following formula (1):

Due to the current flowing through the speaker20equaling to the current Iext flowing through the detecting resistor30, the calculating module54further calculates and obtains a real-time working power of the speaker20according to a following formula (2):

The control module56is capable of comparing the real-time working power of the speaker20with the rated power and adjusting the output voltage of the audio amplifier10according to the compared result. In detail, the control unit56receives the real-time working power of the speaker20from the calculating module54and compares the real-time working power with the rated power. When the real-time working power is less than the rated power, the control module56controls the audio amplifier10remaining output voltage value Vo. When the real-time working power equals to or exceeds the rated power, which indicates that the speaker20works abnormally and may be damaged. In this way, the control module56adjusts the output voltage of the audio amplifier10until the real-time working power of the speaker20is less than the rated power.

FIG. 2shows an embodiment of a method for adjusting a power of the speaker20includes the following steps.

In step1, the audio amplifier10provides a working voltage to the speaker20. The working voltage value provided by the audio amplifier10is Vo. The audio amplifier10, the speaker20, and the detecting resistor30form a current loop.

In step2, the control unit50defines a rated power of the speaker10. When a working power of the speaker20is less than the rated power, the speaker20works normally. When the working power equals to or is out of the rated power, the speaker20works abnormally and may be damaged.

In step3, the A/D convertor52detects a real-time voltage Vext of the detecting resistor30, converts the detected voltage to a digital signal, and transmits the digital signal to the calculating module54.

In step4, the calculating module54calculates and obtains a real-time current flowing through the speaker20according to the detected voltage and a resistance of the detecting resistor30.

In step5, the calculating module54further calculates and obtains a real-time working power of the speaker20according to the real-time current flowing through the speaker20and the working voltage provided by the audio amplifier10.

In step6, the control module56compares the real-time working power with the rated power of the speaker20and adjusts the output voltage of the audio amplifier10according to the compared result. In detail, when the real-time working power is less than the rated power, step7is implemented. When the real-time working power equals to or is out of the rated power, step8is implemented.

In step7, the control module56controls the audio amplifier10remaining outputting the working voltage value Vo.

In step8, the control module56adjusts the output voltage of the audio amplifier10until the real-time working power of the speaker20is less than the rated power.

In summary, the speaker system of this embodiment of the disclosure can detect a working power of the speaker20in real-time by detecting a voltage of the detecting resistor30, and determines whether the working power equals to or exceeds a rated power of the speaker20, thereby effectively and accurately adjusting the working power of the speaker20to prevent the speaker10from damage.

In the present specification and claims, the word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. Further, the word “comprising” does not exclude the presence of elements or steps other than those listed.

It is to be also understood that even though numerous characteristics and advantages of exemplary embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of arrangement of parts within the principles of this disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.