Semiconductor device and capacitance sensor device

A semiconductor device, comprising:

• a first electrode pad and a second electrode pad for externally connecting two electrodes at ends of a series circuit in which a sensor capacitor that has a capacitance that changes according to an environmental change and a first capacitor are connected in series;
• a capacitance circuit having a reference capacitance that supplies a threshold value for determining whether or not the capacitance of the sensor capacitor has changed;
• and
• a determination circuit that includes a first relay terminal and a second relay terminal,
• wherein the determination circuit is configured to:
• send a charging current from the first relay terminal to one of the two electrodes at the ends of the series circuit;
• compare a size of a potential of the first relay terminal and a size of a potential of the second relay terminal;
• and determine whether a capacitance of the sensor capacitor has changed or not based on a comparison result.

A capacitance sensor device for sensing a capacitance change indicative of an environmental change, comprising:

• a sensor capacitor that changes a capacitance according to the environmental change;
• a capacitor having a pair of electrodes, one of the pair of electrodes being connected to one electrode of the sensor capacitor;
• a capacitance circuit having a reference capacitance that supplies a threshold value for determining whether or not the capacitance of the sensor capacitor has changed;
• and
• a determination circuit that includes a first relay terminal and a second relay terminal,
• wherein the determination circuit is configured to:
• send a charging current from the first relay terminal to another of the pair of electrodes of the capacitor;
• compare a size of a potential of the first relay terminal and a size of a potential of the second relay terminal;
• and determine whether a capacitance of the sensor capacitor has changed or not based on a comparison result.