Output driver and pre-charging method thereof

The invention provides an output driver and pre-charging method thereof for an audio system. The output driver includes a pre-charge circuit. The pre-charge circuit includes a charging amplifier and a feedback bias circuit. The charging amplifier includes an output node for coupling to a capacitive load, a first input node for receiving a reference voltage, a second input node for coupling to the output node of the charging amplifier, and a bias node for receiving a bias current. An output current of the charging amplifier varies with the bias current. The feedback bias circuit is coupled to the output node to sense an output voltage of the charging amplifier, and configured to provide the bias current that varies with the output voltage of the charging amplifier. 本发明提供了一种输出驱动器及其预充电方法用于音频系统，其包括预充电路。预充电路包括充电放大器和回授偏压电路。充电放大器包括用于耦接电容性负载的输出节点、用于接收参考电压的第一输入节点、用于耦接充电放大器的输出节点的第二输入节点以及用于接收偏压电流偏压节点。充电放大器的输出电流随着偏压电流而改变。回授偏压电路耦接输出节点以感测充电放大器的输出电压，并被配置为提供偏压电流而使其随着充电放大器的输出电压而改变。