| 摘要 |
PURPOSE:To eliminate the need for a booster circuit so as to greatly reduce a chip area by providing a test control pad, a test signal pad, a high potential detection circuit, a level shift circuit and a MOS transistor. CONSTITUTION:High electric potential is applied to a test control pad 31 during a test, and test potential whose signal level is higher than source potential is applied to a test signal pad 32 during the test. A drive signal Vdrv is supplied to the gate of a transistor Q3 and the test potential applied to the pad 32 is introduced into the transistor as Vtest. This constitution allows a test control signal for use in controlling a test mode to be generated by detection of high voltage inputted from outside a chip. Also, the high voltage is used as the power supply of a level shift circuit 2; that is, the high voltage applied from the outside is used as both signal and power supply, so the need for a booster circuit is eliminated, resulting in great reduction in the chip area. |
