Abstract: A signal processing system includes a digital signal processing circuit, a power management unit, and a digital control circuit. The power management unit provides a first voltage to the digital signal processing circuit. When in a calibration mode the digital control circuit controls the power management unit to set the first voltage at a minimum preset value, controls the digital signal processing circuit to operate under a first calibration target frequency, triggers the digital signal processing circuit to perform a built-in self-test, raises the first voltage when the built-in self-test fails, triggers the digital signal processing circuit to perform the built-in self-test again, and stores the first calibration target frequency and a value of the first voltage corresponding to the first calibration target frequency to a non-volatile memory when the built-in self-test has succeeded.

Abstract: An audio codec circuit includes a voltage detecting circuit, an output processing circuit, a digital-to-analog conversion circuit, and an audio amplifying circuit. The voltage detecting circuit is configured to detect an input voltage of an input power. The output processing circuit obtains a first output compensation value according to the input voltage, an output circuit parameter, and a first output spec. The output processing circuit processes a digital audio and compensates the processed audio by the first output compensation value. The digital-to-analog conversion circuit is configured to perform digital-to-analog conversion on the compensated audio to obtain an analog audio. The audio amplifying circuit is configured to amplify the analog audio and output the amplified audio.

Abstract: A state detection device in an audio interface includes: a first voltage detection circuit, a second voltage detection circuit and a state determination circuit. The first voltage detection circuit is coupled to a first contact and a second contact of an audio jack socket, for detecting a voltage across the first contact and the second contact to generate a first detection value. The second voltage detection circuit is coupled to a third contact of the audio jack socket, for detecting a voltage on the third contact to generate a second detection value. The state determination circuit is coupled to the first voltage detection circuit and the second voltage detection circuit, for determining a water ingress state of the audio jack socket according to the first detection value, and a connector type of an audio plug that is inserted into the audio jack socket according to the second detection value.

Abstract: A state detection device in an audio interface includes: a first voltage detection circuit, a second voltage detection circuit and a state determination circuit. The first voltage detection circuit is coupled to a first contact and a second contact of an audio jack socket, for detecting a voltage across the first contact and the second contact to generate a first detection value. The second voltage detection circuit is coupled to a third contact of the audio jack socket, for detecting a voltage on the third contact to generate a second detection value. The state determination circuit is coupled to the first voltage detection circuit and the second voltage detection circuit, for determining a water ingress state of the audio jack socket according to the first detection value, and a connector type of an audio plug that is inserted into the audio jack socket according to the second detection value.

Abstract: A signal processing system includes a digital signal processing circuit, a power management unit, and a digital control circuit. The power management unit provides a first voltage to the digital signal processing circuit. When in a calibration mode the digital control circuit controls the power management unit to set the first voltage at a minimum preset value, controls the digital signal processing circuit to operate under a first calibration target frequency, triggers the digital signal processing circuit to perform a built-in self-test, raises the first voltage when the built-in self-test fails, triggers the digital signal processing circuit to perform the built-in self-test again, and stores the first calibration target frequency and a value of the first voltage corresponding to the first calibration target frequency to a non-volatile memory when the built-in self-test has succeeded.

Abstract: An audio codec circuit includes a voltage detecting circuit, an output processing circuit, a digital-to-analog conversion circuit, and an audio amplifying circuit. The voltage detecting circuit is configured to detect an input voltage of an input power. The output processing circuit obtains a first output compensation value according to the input voltage, an output circuit parameter, and a first output spec. The output processing circuit processes a digital audio and compensates the processed audio by the first output compensation value. The digital-to-analog conversion circuit is configured to perform digital-to-analog conversion on the compensated audio to obtain an analog audio. The audio amplifying circuit is configured to amplify the analog audio and output the amplified audio.

Abstract: A USB adapting circuit is suitable for being connected between a USB host and an external device. The USB adapting circuit includes a connecting port, a detecting circuit, a standby circuit and a main circuit. The standby circuit receives a power supply from the USB host and supplies the detecting circuit and the main circuit with the power supply. The detecting circuit is configured to output a connected signal when the external device is connected to the connecting port. The standby circuit outputs an enabling signal in response to the connected signal. The main circuit adapts between the USB host and the external device when receiving the enabling signal. Therefore, the main circuit does not work without receiving the enabling signal, and has a power saving effect.

Abstract: A USB adapting circuit is suitable for being connected between a USB host and an external device. The USB adapting circuit includes a connecting port, a detecting circuit, a standby circuit and a main circuit. The standby circuit receives a power supply from the USB host and supplies the detecting circuit and the main circuit with the power supply. The detecting circuit is configured to output a connected signal when the external device is connected to the connecting port. The standby circuit outputs an enabling signal in response to the connected signal. The main circuit adapts between the USB host and the external device when receiving the enabling signal. Therefore, the main circuit does not work without receiving the enabling signal, and has a power saving effect.

Abstract: An audio playback device that includes an audio receiver module, a loudspeaker module and an audio control circuit is provided. The audio control circuit includes an interface and a gain adjusting module. The interface receives an audio signal from an audio source. Under a first operation mode, the audio signal is transmitted only to the audio receiver module to be playback. Under a second operation mode, the audio signal is transmitted to the audio receiver module and to the loudspeaker module to be playback. The gain adjusting module includes a temperature sensing circuit to sense a temperature of the audio receiver module and a gain adjusting circuit electrically coupled between the audio interface and the audio receiver module to adjust a gain of the audio signal according to the temperature.

Abstract: A detection circuit of an electronic device includes a resistance detecting circuit and a voltage supplying circuit, wherein the detecting circuit is coupled to an input circuit which is coupled to the electronic device and comprises a plurality of resistors respectively coupled to a plurality of switches, wherein the resistance detecting circuit is arranged to detect whether the input circuit has a resistance variation and generate a detecting signal indicative of the resistance variation; and the voltage supplying circuit is coupled to the resistance detecting circuit to supply a first voltage signal, wherein the voltage supplying circuit receives the detecting signal, and selectively switches the first voltage signal to a second voltage signal according to the detecting signal; wherein the resistance detecting circuit determines whether at least one of the plurality of switches is closed according to the second voltage signal.

Abstract: A detection circuit of an electronic device includes a resistance detecting circuit and a voltage supplying circuit, wherein the detecting circuit is coupled to an input circuit which is coupled to the electronic device and comprises a plurality of resistors respectively coupled to a plurality of switches, wherein the resistance detecting circuit is arranged to detect whether the input circuit has a resistance variation and generate a detecting signal indicative of the resistance variation; and the voltage supplying circuit is coupled to the resistance detecting circuit to supply a first voltage signal, wherein the voltage supplying circuit receives the detecting signal, and selectively switches the first voltage signal to a second voltage signal according to the detecting signal; wherein the resistance detecting circuit determines whether at least one of the plurality of switches is closed according to the second voltage signal.

Abstract: A combo-plug detecting circuit for use in an audio CODEC is provided. The combo-plug detecting circuit is used to determine the contact configuration of the audio plug, to ensure that the audio plug belonging to the differential structure can be compatible with the audio CODEC.

Abstract: A combo-plug detecting circuit for use in an audio CODEC is provided. The combo-plug detecting circuit is used to determine the contact configuration of the audio plug, to ensure that the audio plug belonging to the differential structure can be compatible with the audio CODEC.

Abstract: An audio playback device that includes an audio receiver module, a loudspeaker module and an audio control circuit is provided. The audio control circuit includes an interface and a gain adjusting module. The interface receives an audio signal from an audio source. Under a first operation mode, the audio signal is transmitted only to the audio receiver module to be playback. Under a second operation mode, the audio signal is transmitted to the audio receiver module and to the loudspeaker module to be playback. The gain adjusting module includes a temperature sensing circuit to sense a temperature of the audio receiver module and a gain adjusting circuit electrically coupled between the audio interface and the audio receiver module to adjust a gain of the audio signal according to the temperature.

Abstract: Provided herein are a headphone amplifier circuit for a headphone driver, an operation method thereof, and a universal serial bus (USB) interfaced headphone device using the same. The output stage of the headphone amplifier circuit is improved to have a differential output structure so as to effectively solve the crosstalk issue and increase the isolation between the left and the right channels such that the audio content presents a spatial perception and a distance perception more specifically.

Abstract: Provided herein are a headphone amplifier circuit for a headphone driver, an operation method thereof, and a universal serial bus (USB) interfaced headphone device using the same. The output stage of the headphone amplifier circuit is improved to have a differential output structure so as to effectively solve the crosstalk issue and increase the isolation between the left and the right channels such that the audio content presents a spatial perception and a distance perception more specifically.

Abstract: An electronic apparatus comprises a switch, a processing unit, a functional unit and a power management unit. The function unit has a timer. The power management unit is coupled to the processing unit and the function unit. The processing unit and the function unit receive a switch signal generated by the switch. The processing unit generates a power-down signal after detecting a change in the logic level of the switch signal received for a first predetermined time. The timer starts counting upon detecting a change in the logic level of the switch signal, and executes a power-down procedure after the timer has counted to a second predetermined time. The second time is less than the first predetermined time. The function unit completes the power-down procedure before the power management unit receives the power-down signal and stops powering the processing unit and the function unit.

Abstract: The present invention discloses an audio codec with a jack detection function and an audio jack detection method. An embodiment of the audio codec comprises: a first-contact signal input end operable to electrically connect with a sleeve contact of a plug and receive a first-contact signal indicating the presence or absence of the plug; a second-contact signal input end operable to electrically connect with a ring contact or the sleeve contact of the plug and receive a second-contact signal indicating the presence or absence of the plug; a plug detecting circuit coupled to the first-contact or second-contact signal input end and operable to detect whether a voltage level of the first-contact or second-contact signal has changed to thereby generate a plug detection signal; and a control circuit coupled to the plug detecting circuit and operable to determine the presence or absence of the plug according to the plug detection signal.

Abstract: The present invention provides a signal processing circuit and a signal processing method applied to a headset. In the present invention, the signal processing circuit adjusts gain and phase of a left channel signal and a right channel signal to generate a first adjust signal, and a recorded sound from a microphone is added by the first adjust signal to cancel a coupled signal. In addition, the signal processing circuit adjusts gain and phase of the right channel signal to generate a second adjust signal, and the right channel signal is added by the second adjust signal to cancel a coupled signal; and the signal processing circuit adjusts gain and phase of the left channel signal to generate a third adjust signal, and the left channel signal is added by the third adjust signal to cancel a coupled signal.

Abstract: The present invention discloses an audio device having haptic compensation function capable of compensating a haptic effect according to a power measuring result and an audio signal. An embodiment of the audio device comprises: an audio signal generating circuit operable to generate an audio signal; a power measuring circuit operable to measure a remaining electric quantity of a power source and thereby generate a power measuring result; and a haptic compensating circuit, coupled to the audio signal generating circuit and the power measuring circuit, operable to adjust a gain of the audio signal or the derived signal thereof according to the power measuring result and thereby output a haptic compensation signal which is used to compensate the haptic effect.