Supply voltage detecting circuit, method of operating the same, electronic device comprising the same and electronic system comprising the same

A supply voltage detecting circuit comprising:

• trim resistance circuitry including an input terminal, an output terminal, and a plurality of trim resistors connected to each other in series, the input terminal configured to receive a supply voltage;
• a first transistor having a first source/drain terminal electrically connected to the output terminal;
• a plurality of trim switches that each have first ends connected between the plurality of trim resistors, have second ends connected to a gate terminal of the first transistor, and each of the plurality of trim switches is configured to perform a switching operation in response to a switching control signal;
• and
• a switch controller configured to provide the switching control signal for turning on a first trim switch of the plurality of trim switches based on a process variation of the first transistor when the supply voltage reaches a stable level, and
• the first trim switch configured to apply a voltage dropped by at least some of the plurality of trim resistors from the supply voltage to the gate terminal of the first transistor in response to being turned on.