Patent ID: 8222952
Filing Date: 2012-07-17
Classification: H03K

Abstract:
1. A semiconductor device comprising: a first substrate voltage generating circuit that generates a substrate voltage of one of first field effect transistors of a first conductivity type and second field effect transistors of a second conductivity type in a complementary field effect transistor circuit; a first replica transistor that is a replica of one of the first and second field effect transistors, the first replica transistor being diode-connected; and a first voltage applying circuit that applies a voltage of a predetermined first voltage value between an anode and a cathode of the first replica transistor, wherein a substrate voltage of the first replica transistor is the substrate voltage generated by the first substrate voltage generating circuit, and the first substrate voltage generating circuit controls the substrate voltage of the first replica transistor so that a value of a current flowing in the first replica transistor becomes equal to a predetermined first target value, the first voltage applying circuit comprises a noninverting amplifier that includes first and second input terminals and a first output terminal, the first substrate voltage generating circuit comprises a comparator that includes third and fourth input terminals and a second output terminal, the semiconductor device further comprises a first input voltage generating circuit that generates an input voltage of the third input terminal, the first output terminal and the fourth input terminal are connected to each other, the voltage of the first voltage value is input to the first input terminal, the first replica transistor is inserted in a forward direction between the second input terminal and a ground, the first input voltage generating circuit generates a target value for controlling an output voltage of the first output terminal determined by the first target value, the first input voltage generating circuit outputting the target value to the third input terminal, and the comparator in the first substrate voltage generating circuit generates the substrate voltage of the one of the first and second field effect transistors, based on the voltage that is input to the third input terminal and the output voltage of the first output terminal that is input to the fourth input terminal, the comparator outputting the substrate voltage from the second output terminal.