Patent ID: 8519755

Claim:
A power-on reset circuit, comprising: a bandgap reference circuit to which a power supply voltage is supplied, and which outputs a predetermined first voltage value; a first start-up circuit, causing the bandgap reference circuit to start a stable operation when a value of the power supply voltage becomes a first threshold value or higher, wherein: at least one input control terminal of the first start-up circuit is tied to the power supply voltage, and a first output terminal of the first start-up circuit is tied to a first input terminal of the bandgap reference circuit and a second output terminal of the first start-up circuit is tied to a second input terminal of the bandgap reference circuit; a voltage dividing circuit including: a switch and a first resistor provided in series between a power supply voltage terminal to which the power supply voltage is supplied and an output terminal of the voltage dividing circuit; and a second resistor provided between the output terminal of the voltage dividing circuit and a ground terminal, the voltage dividing circuit outputting a second voltage value from the output terminal of the voltage dividing circuit; a second start-up circuit which causes the switch of the voltage dividing circuit to close when the value of the power supply voltage becomes a second threshold value or higher which is greater than the first threshold value; and a voltage comparison circuit receiving the predetermined first voltage value output from the bandgap reference circuit and the second voltage value output from the voltage dividing circuit, and outputting a reset level voltage value when the second voltage value is smaller than the predetermined first voltage value and outputting a power-supply voltage level voltage value if the second voltage value becomes the predetermined first voltage value or higher.