A variable voltage generation circuit includes an amplifier, a P-type metal-oxide-semiconductor transistor, at least one variable resistor, and a lower resistor. Each variable resistor includes M resistors and M switches. An ith switch of the M switches has a first terminal coupled to a first terminal of the variable resistor, and a second terminal. An ith resistor has a first terminal coupled to the second terminal of the ith switch, and a second terminal coupled to a first terminal of an (i+1)th resistor, where 2≦M, 1≦i≦M, and i and M are natural numbers. Therefore, the variable voltage generation circuit outputs at least one variable voltage according to a reference voltage, the at least one variable resistor, and the lower resistor.