Abstract: Disclosed is a circuit for voltage regulation, the circuit including: an amplifier operable to generate an amplifier output signal according to a reference voltage and a negative feedback voltage; an adaptive pre-driver operable to generate a bias current according to the amplifier output signal or according to the amplifier output signal and a current-dependent signal that varies with the variation of an output current, in which the bias current varies with the variation of the output current; a driving circuit operable to generate an output voltage and the output current according to the amplifier output signal; and a negative feedback circuit operable to generate the negative feedback voltage according to the output voltage. Since the bias current varies with the variation of the output current, the output impedance of the adaptive pre-driver varies with the variation of the output current so that the stability of the circuit is improved.

Abstract: Disclosed is a circuit for voltage regulation, the circuit including: an amplifier operable to generate an amplifier output signal according to a reference voltage and a negative feedback voltage; an adaptive pre-driver operable to generate a bias current according to the amplifier output signal or according to the amplifier output signal and a current-dependent signal that varies with the variation of an output current, in which the bias current varies with the variation of the output current; a driving circuit operable to generate an output voltage and the output current according to the amplifier output signal; and a negative feedback circuit operable to generate the negative feedback voltage according to the output voltage. Since the bias current varies with the variation of the output current, the output impedance of the adaptive pre-driver varies with the variation of the output current so that the stability of the circuit is improved.

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 discloses a gain control circuit capable of easing leakage current influence. According to an embodiment of the present invention, the gain control circuit comprises: at least one signal input end for receiving at least one input signal; a signal output end for outputting an output signal; an amplifier coupled between an amplifier input end and the signal output end; and a plurality of gain schemes. Each of the gain schemes is set between the at least one signal input end and the signal output end; and when one of the gain schemes is activated to generate the output signal, the rest gain schemes are inactivated to stop gain production and concurrently discharge leakage currents through their respective grounding paths.

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 discloses a gain control circuit capable of easing leakage current influence. According to an embodiment of the present invention, the gain control circuit comprises: at least one signal input end for receiving at least one input signal; a signal output end for outputting an output signal; an amplifier coupled between an amplifier input end and the signal output end; and a plurality of gain schemes. Each of the gain schemes is set between the at least one signal input end and the signal output end; and when one of the gain schemes is activated to generate the output signal, the rest gain schemes are inactivated to stop gain production and concurrently discharge leakage currents through their respective grounding paths.