A driving circuit comprising a reference-voltage circuit, an amplifier, an adjusting circuit, and a current-setting circuit. The reference-voltage circuit is used for generating a reference voltage. The amplifier comprises a first input terminal used for receiving the reference voltage, a second input terminal used for receiving feedback voltage from a load, and an output terminal used for outputting an output current to the load. The adjusting circuit is used for adjusting a voltage of the load when a resistance of the load changes. The current-setting circuit is used for setting a value of the output current based on the feedback voltage.