Patent ID: 7710413

Claim:
A voltage regulator generating a second voltage having a desired potential difference from a first voltage, the voltage regulator comprising: a level shifting circuit unit shifting a voltage level of the first voltage to a target voltage level to output the shifted first voltage; a voltage-to-current converting circuit unit varying a magnitude of an output current to output the current while changing a direction of the current by varying a voltage to larger and smaller values with respect to a center voltage of an arbitrarily variable voltage range; and an adder-subtracter circuit unit having a first terminal on one side, the first terminal being connected to an output terminal of the level shifting circuit unit, and a second terminal on the other side, the second terminal being connected to a resistance element disposed between the second terminal and an output terminal of the adder-subtracter circuit, the resistance element allowing an output current of the voltage-to-current converting circuit unit to flow therethrough as a bias current, wherein a bias voltage generated by the bias current and the resistance element is used as an adjustment voltage and a voltage generated by addition and subtraction of the adjustment voltage to and from a voltage output from the level shifting circuit unit is output from the adder-subtracter circuit unit as the second voltage, wherein the voltage-to-current converting circuit unit changes a direction of the current into an opposite direction when the voltage-to-current converting circuit unit varies the voltage on a side of the voltage lower than the center voltage to a direction when the voltage-to-current converting circuit unit varies the voltage on a side of the voltage higher than the center voltage.