1. An amplifier circuit, comprising; a first input node to receive an input current, a second input node to receive an input reference voltage, and an output node; a first supply voltage node and a second supply voltage node; a load device connected between the output node and the first supply voltage node; an operational amplifier having a first input terminal connected to the first input node, a second input terminal connected to the second input node, and an output terminal; a current source connected to the output terminal of the operational amplifier and to the second supply voltage node; and a bipolar transistor having a base terminal connected to the first input node, a collector terminal connected to the output node, and an emitter terminal connected to the current source, wherein the operational amplifier, the current source, and the bipolar transistor form a feedback loop that generates and maintains a bias voltage on the first input node based on the input reference voltage applied to the second input node, wherein the bipolar transistor amplifies the input current that is input to the base terminal and generates a collector current as the amplified input current, and wherein the load device converts the collector current of the bipolar transistor to an output voltage on the output node.