| 摘要 |
PROBLEM TO BE SOLVED: To enable screening inspection and the like with a power-supply voltage being changed minutely at the time of burn-in operation. SOLUTION: In the burn-in operation and the like, wherein a power-supply voltage is specified value or more, the output of a high-voltage detecting circuit 202 becomes the high level, and a node 4 also becomes the high level. Therefore, an NMOS transistor T2-1 is conducted, and a node 2 is connected to a power supply terminal Vcc. The reference voltage of the node 2 becomes the value, which is obtained by subtracting the threshold voltage of the transistor T201 from the power supply voltage. Then, after an operation switching signal (high level) is inputted into an input 1, the high-level state of the node 4 is maintained by an AND gate 203 even if the power supply voltages is decreased to the value less than the preset value. Therefore, the potential of an output node 1 is finely changed in correspondence with the change in power supply voltage, and screening inspection and the like can be performed excellently. |
