Variable voltage generation circuit

摘要

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.

主权项

1. A variable voltage generation circuit, comprising:
an amplifier having a first input terminal for receiving a first voltage, a second input terminal for receiving a reference voltage, a third input terminal, and an output terminal; a P-type metal-oxide-semiconductor transistor having a first terminal for receiving the first voltage, a second terminal coupled to the output terminal of the amplifier, and a third terminal; a first variable resistor having a first terminal coupled to the third terminal of the P-type metal-oxide-semiconductor transistor for outputting a first variable voltage, and a second terminal coupled to the third input terminal of the amplifier, wherein the first variable resistor comprises:
M resistors, wherein the M resistors are arranged in series; andM switches, wherein an ith switch of the M switches has a first terminal coupled to the first terminal of the first variable resistor, and a second terminal, wherein an ith resistor of the M resistors has a first terminal coupled to the second terminal of the ith switch, and a second terminal coupled to a second terminal of an (i+1)th switch;wherein a second terminal of an Mth resistor is coupled to the second terminal of the first variable resistor, 2≦M, 1≦i