Semiconductor device and method of generating power on reset signal

A semiconductor device, comprising:

• a voltage divider circuit dividing a power supply voltage to obtain a first voltage and a second voltage having voltage values different from each other;
• a first transistor receiving the first voltage at a control electrode to generate a first current;
• a second transistor receiving the second voltage at a control electrode to generate a second current, wherein the first transistor and the second transistor are metal oxide semiconductor (MOS) transistors that have aspect ratios different from each other when a ratio of a gate width to a gate length (gate width/gate length) is set as the aspect ratio;
• a current comparing part comparing the first current and the second current to generate a current comparison result signal representing a comparison result;
• and
• a reset signal generating part generating a power on reset signal having a first level that prompts reset or a second level that prompts reset cancelation based on the current comparison result signal,
• wherein the current comparing part comprises:
• a third transistor having a gate connected to the gate of the second transistor and causing a current corresponding to the second current to flow to a first node;
• a current mirror circuit copying the current flowing to the first node and causing the copied current to flow to a second node;
• and
• a fourth transistor having a gate connected to the gate of the first transistor and drawing a current corresponding to the first current from the second node,
• wherein the current comparing part supplies a signal representing a voltage of the second node as a signal level as the current comparison result signal to the reset signal generating part, and
• the reset signal generating part comprises at least one inverter that outputs a signal obtained by inverting a phase of the current comparison result signal or inverting a phase of the signal with an inverted phase as the power on reset signal.