Monitor circuit, semiconductor integrated circuit, semiconductor device, and method of controlling power supply voltage of semiconductor device

15 A semiconductor device comprising:

• (a) a poser supply IC that generates an external power supply voltage;
• and
• (b) a semiconductor integrated circuit including:
• (i) a functional block that is supplied with the external power supply voltage as an internal power supply voltage via a power supply voltage line;
• (ii) a monitor circuit that measures at least a value of the internal power supply voltage;
• and
• (iii) a control unit that controls a value of the external power supply voltage based on a measurement result of the monitor circuit,
• wherein the monitor circuit includes:
• (1) a reference voltage generating unit that generates a first reference voltage and a second reference voltage that is generated baaed on a ground voltage which is common to the first reference voltage, the second reference voltage being different in value from that of the first reference voltage;
• (2) a first amplifier unit that amplifies a differential voltage between the first reference voltage and the second reference voltage;
• (3) a second amplifier unit that amplifies a differential voltage between the internal power supply voltage and the first reference voltage;
• and
• (4) a comparator unit that compares an amplification result of the first amplifier unit and an amplification result of the second amplifier unit with each other and outputs a comparison result as the measurement result.

A method of controlling a power supply voltage of a semiconductor device comprising:

• (a) a step of measuring a value of an internal power supply voltage of a functional block, an external power supply voltage generated outside a semiconductor integrated circuit which is supplied to the functional block as the internal power supply voltage via a power supply voltage line;
• and
• (b) a step of controlling a value of the external power supply voltage based on a result of the measurement,
• wherein the step of measuring a value of the internal power supply voltage includes at least;
• (i) a step of generating a first reference voltage and a second reference voltage that is generated based on a ground voltage which is common to the first reference voltage, the second reference voltage being different in value from that of the first reference voltage;
• (ii) a step of amplifying a differential voltage between the first reference voltage and the second reference voltage;
• (iii) a step of amplifying a differential voltage between the internal power supply voltage and the first reference voltage;
• and
• (iv) a step of comparing an amplification result of the differential voltage between the first reference voltage and the second reference voltage and an amplification result of the differential voltage between the internal power supply voltage and the first reference voltage with each other and outputting a comparison result as the measurement result.