Semiconductor device
This invention allows for stable operation of a circuit to which an output voltage is supplied. The invention resides in a semiconductor device comprising a VREF 1 regulator to which a reference voltage Vref 1 relative to a first potential is input; and an output circuit which generates an output voltage Vint that is proportional to a voltage on its input terminal relative to a second potential. The VREF 1 regulator comprises a constant current source which generates a constant current having a current value that is proportional to the reference voltage Vref 1 ; and a first resistor element which is supplied with the constant current, one end of which is coupled to the input terminal of the output circuit and the other end of which is coupled to the second potential.
1. A semiconductor device, comprising:
a reference voltage regulator to which a reference voltage relative to a first potential is input; and
an output circuit which generates an output voltage that is proportional to a voltage on its input terminal relative to a second potential,
wherein the reference voltage regulator includes:
a constant current source which generates a constant current having a current value that is proportional to the reference voltage; and
a first resistor element which is supplied with the constant current, one end of which is coupled to the input terminal of the output circuit and the other end of which is coupled to the second potential,
wherein the reference voltage regulator further includes a current regulator which generates an internal current that is proportional to the reference voltage and drives the constant current source to generate the constant current that is proportional to the internal current,
wherein the current regulator includes:
an operational amplifier with an inverting input terminal to which the reference voltage is applied;
a first MOS transistor having a source being coupled to a predefined power supply, a gate being coupled to an output of the operational amplifier, and a drain being coupled to a noninverting input terminal of the operational amplifier; and
a second resistor element, one end of which is coupled to the drain of the first MOS transistor and the other end of which is coupled to the first potential,
wherein the constant current source includes:
a second MOS transistor of the same conductivity type as the first MOS transistor, the second MOS transistor having a source being coupled to the predefined power supply, a gate being coupled to the output of the operational amplifier, and a drain through which the constant current is supplied to the first resistor element.
2. The semiconductor device according to 1 , wherein the first and second potentials are respective potentials of two points having a potential difference therebetween in ground wiring.