Method and apparatus to control output power of a digital power amplifier optimized to a headphone and a portable audio player having the same
First Claim
1. An apparatus to control an output power of a digital amplifier in a digital audio amplification device, the apparatus comprising:
- a signal processing unit to power amplify a pulse signal and to convert the pulse signal into a direct current (DC) voltage;
an impedance measuring unit to connect a resistance device between the signal processing unit and a speaker unit and to detect a voltage value applied to the resistance device and the speaker unit; and
a micom unit to generate a pulse signal having a predetermined duty cycle in the signal processing unit if the speaker unit is connected to the device, to determine an impedance of the speaker unit based on the voltage value detected by the impedance measuring unit, to control a power amplification by providing a voltage level control signal to the signal processing unit according to the determined impedance, and to control an audio level in an audio reproduction mode accordingly.
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Accused Products
Abstract
A method and apparatus to control output power of a digital amplifier capable of automatically determining an impedance of an earphone or headphone connected to a portable audio device and outputting a power that is optimized according to the impedance. The apparatus is usable with a digital amplification device and includes a signal processing unit to convert a pulse signal into a direct current (DC) voltage by power-amplifying the pulse signal, an impedance measuring unit to connect a resistance device between the signal processing unit and a speaker unit and to detect a voltage value applied to the resistance device and the speaker unit, and a micom unit to generate a pulse signal having a predetermined duty cycle in the signal processing unit if the speaker unit is connected to the device, to determine an impedance of the speaker unit based on the voltage value detected by the impedance measuring unit, to control a power amplification by providing a voltage level control signal to the signal processing unit according to the determined impedance, and to control an audio level in an audio reproduction mode accordingly.
56 Citations
24 Claims
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1. An apparatus to control an output power of a digital amplifier in a digital audio amplification device, the apparatus comprising:
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a signal processing unit to power amplify a pulse signal and to convert the pulse signal into a direct current (DC) voltage;
an impedance measuring unit to connect a resistance device between the signal processing unit and a speaker unit and to detect a voltage value applied to the resistance device and the speaker unit; and
a micom unit to generate a pulse signal having a predetermined duty cycle in the signal processing unit if the speaker unit is connected to the device, to determine an impedance of the speaker unit based on the voltage value detected by the impedance measuring unit, to control a power amplification by providing a voltage level control signal to the signal processing unit according to the determined impedance, and to control an audio level in an audio reproduction mode accordingly. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A digital amplifier usable in a portable audio device, the amplifier comprising:
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a signal processing unit having a variable power supply unit to output a variety of voltages, the signal processing unit receiving an audio signal and amplifying the audio signal based on a DC voltage currently output by the variable power supply unit;
an impedance measuring unit to measure an impedance value of any speaker unit connected to the portable audio device and to output an impedance detection signal; and
a micom unit to receive the impedance detection signal and to control the variable power supply unit to update the DC voltage currently output based on the measured impedance value indicated by the impedance detection signal.
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8. A portable audio device, comprising:
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a digital amplifier to amplify an audio signal based on a power supply level of a power supply; and
a power supply control unit to vary the power supply level of the power supply based on an impedance of at least one speaker unit connected to the digital amplifier. - View Dependent Claims (9, 10, 11)
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12. A portable audio device, comprising:
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an output port;
an audio unit to output an audio signal; and
an amplifier to receive the audio signal from the audio unit and to amplify the audio signal based on an impedance value detected at the output port. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A portable audio device, comprising:
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a digital amplifier to amplify an audio signal based on a power supply level of a power supply; and
an apparatus to control an output power of the digital amplifier by varying the power supply level of the power supply based on an impedance of at least one speaker unit connected to the digital amplifier, the apparatus including a signal processing unit to power amplify a pulse signal and to convert the pulse signal into a direct current (DC) voltage, an impedance measuring unit to connect a resistance device between the signal processing unit and the at least one speaker unit and to detect a voltage value applied to the resistance device and the at least one speaker unit, and a micom unit to generate a pulse signal having a predetermined duty cycle in the signal processing unit if the at least one speaker unit is connected to the portable audio device, to determine the impedance of the at least one speaker unit based on the voltage value detected by the impedance measuring unit, to control a power amplification by providing a voltage level control signal to the signal processing unit according to the determined impedance, and to control an audio level in an audio reproduction mode accordingly.
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20. A portable audio device, comprising:
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a signal processing unit having another terminal to generate a voltage signal in a headphone impedance measuring mode;
a terminal to be connected to an external headphone;
an impedance measuring unit to be selectively connected between the terminal and the another terminal to generate one of a first value and a second value according to the voltage signal corresponding to a characteristic of the external headphone; and
a processor unit to control the signal processing unit to generate one of a first audio reproducing signal and a second audio reproducing signal according to the one of the first value and the second value.
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21. A method of controlling output power of a digital audio amplification device, the method comprising:
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if a speaker unit is connected to the digital audio amplification device, setting an impedance measuring mode and generating an arbitrary pulse signal;
converting the arbitrary pulse signal into a DC voltage;
applying the DC voltage to a resistance device connected to the speaker unit and detecting a voltage between the resistance device and the speaker unit;
determining an impedance of the speaker unit based on the detected voltage; and
adjusting a level of audio being reproduced by controlling switching power-amplification with respect to the determined impedance of the speaker unit. - View Dependent Claims (22, 23, 24)
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Specification