Abstract: A line driver includes a first resistive component, a second resistive component, an operational amplifier and an adjustable current mirror array circuit. A first terminal of the second resistive component and the first resistive component are coupled to a node, and a second terminal of the second resistive component is coupled to an output terminal. The operational amplifier receives a common mode voltage through the first resistive component, and generates a first signal and a second signal according to the common mode voltage and an input signal. The adjustable current mirror array circuit generates a first current to the node and a second current to the output terminal in response to the first and second signals, and adjusts a ratio of the second current to the first current in response to multiple control bits so as to set an output impedance of the output terminal.

Abstract: An audio player device includes a digital-to-analog converter (DAC), a startup circuit, a multiplexer and an output amplifier. The DAC converts audio data into a first signal and a second signal. The startup circuit gradually increases a level of a startup voltage according to a reference voltage during a predetermined period. The multiplexer outputs the startup voltage as a control voltage during the predetermined period, and switches to output the reference voltage as the control voltage after the predetermined period has elapsed. The output amplifier generates an audio signal according to the control voltage, the first signal and the second signal. The control voltage is used to set a common mode voltage of the output amplifier.

Abstract: A wired transceiver includes an output stage circuit and an input stage circuit. The output stage operates in one of a first mode and a second mode according to a mode control signal, and transmits multiple output signals to multiple output pads and receives a first set of bias voltages to provide a first overvoltage protection in the first mode, and stops transmitting the output signals and receives a second set of bias voltages to provide the overvoltage protection in the second mode. The input stage circuit receives multiple input signals from the output pads when the output stage circuit operates in the second mode, and attenuates the input signal to provide a second overvoltage protection.

Abstract: A line driver includes a first resistive component, a second resistive component, an operational amplifier and an adjustable current mirror array circuit. A first terminal of the second resistive component and the first resistive component are coupled to a node, and a second terminal of the second resistive component is coupled to an output terminal. The operational amplifier receives a common mode voltage through the first resistive component, and generates a first signal and a second signal according to the common mode voltage and an input signal. The adjustable current mirror array circuit generates a first current to the node and a second current to the output terminal in response to the first and second signals, and adjusts a ratio of the second current to the first current in response to multiple control bits so as to set an output impedance of the output terminal.