A differential reference voltage generator generates a first differential reference voltage and a second differential reference voltage. The differential reference voltage generator includes a first operational amplifier, a first transistor, a first resistor, and a second resistor. The first operational amplifier has a negative terminal adapted to receive a reference voltage. The first transistor has a source receiving a power supply voltage and has a gate electrically connected to an output terminal of the first operational amplifier. The first resistor has a first terminal electrically connected to a drain of the first transistor, and has a second terminal electrically connected to a positive terminal of the first operation amplifier. The second resistor has a first terminal electrically connected to the second terminal of the first resistor, and a second terminal electrically connect to a current mirror.