| 摘要 |
<p>When the value of a power supply voltage (VDD) becomes a first threshold value or higher, a first start-up circuit (20) causes a band gap reference circuit (10) to start a stable operation and a first voltage value (V A ) is output from the band gap reference circuit (10). When the value of the power supply voltage becomes a second threshold value or higher which is greater than the first threshold, a second start-up circuit (40) turns on a PMOS transistor (MP 3 ) of a voltage dividing circuit (30), and a second voltage value (V B ) output from the voltage dividing circuit (30) becomes a value, which is derived by dividing the value of the power supply voltage according to the resistance ratio of resistors (R 31 , R 32 ). From a voltage comparison circuit (50), a reset level voltage value is output when the second voltage value (V B ) is smaller than the first voltage value (V A ), and a power-supply voltage level voltage value is output if the second voltage value (V B ) becomes the first voltage value (V A ) or higher,.</p> |
