Title: Method and apparatus to control output power of a power amplifier and audio player having the same
Application Number: 200610132250 Application Date: 2006.10.13
Publication Number: 1960175 Publication Date: 2007.05.09
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: H03G3/20;H03F3/217;G10H1/00;H04R3/00;H04R27/00
Applicant(s) Name: Samsung Electronics Co., Ltd. Address:
Inventor(s) Name: Song Young-suk;Kim Zhun-woo
Attorney & Agent: hanmeng xing tanchang chi
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.
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