A potential detecting circuit for detecting a potential, and for determining whether or not the detected potential has attained a predetermined detection level, said circuit receiving a power supply voltage variable between upper and lower values, comprising:
- an output node;
- a reference current supplying circuit coupled to a source of said power supply voltage for supplying a constant reference current to said output node;
- a detection node to which said potential is applied;
- and
- comparing current supplying means responsive to the potential applied to said detection node, for supplying a comparing current to said output node, wherein said comparing current supplying means includes:
- a detection resistance element through which a detection current flows in response to the potential applied to said detection node,
- a current mirror circuit responsive to said detection current for controlling said supplying of said comparing current, and
- a first transistor connected between said detection resistance element and said current mirror circuit, and said first transistor having a gate electrode to which a first reference potential is applied,
- said detection resistance element includes a second transistor having a gate electrode to which a second reference potential is applied.