Amplifier circuit and circuit system using the same

A circuit system, comprising:

• a load, electrically connected to an output stage of an amplifier circuit;
• and
• the amplifier circuit, comprising:
• the output stage, comprising a first P-type transistor and a first N-type transistor, wherein the first P-type transistor is electrically connected to the first N-type transistor in series;
• a first current source, providing a first input current;
• a second current source, providing a first bias current;
• a third current source, providing a second input current;
• a fourth current source, providing a second bias current;
• and
• a voltage clamping circuit, receiving a first bias voltage and a second bias voltage lower than the first bias voltage, and having a first end and a second end, wherein the first end is electrically connected to the first current source, the second current source and a gate of the first P-type transistor, and the second end is electrically connected to the third current source, the fourth current source and a gate of the first N-type transistor;
• wherein when the second input current is a positive current and the first input current is a negative current or zero current, the first end provides a first clamping voltage greater than the first bias voltage to the gate of the first P-type transistor, when the first input current is positive current and the second input current is negative current or zero current, the second end provides a second clamping voltage lower than the second bias voltage to the gate of the first N-type transistor.