公开(公告)号：JPH06216728A

公开(公告)日：1994-08-05

申请号：JP27426093

申请日：1993-11-02

Applicant: ADVANCED MICRO DEVICES INC

Inventor： HERUMAN EMU CHIYAN ,  BURATSUDORII SHIYAAPEEGAISURAA

IPC: H03K5/13 ,  G11C7/24 ,  G11C16/22 ,  H03K19/003 ,  H03K19/173 ,  H03K19/177

Abstract: PURPOSE: To protect a programmable logic device from an unwanted input overshoot voltage by activating the editing mode of logic device only when inputting an overvoltage during the duration longer than predetermined time delay. CONSTITUTION: When the overvoltage is detected at the input of circuit 10, a circuit 20 activates a time delay circuit 30. When the time impressing the overvoltage to the input of circuit 10 is longer than the predetermined time constant of time delay circuit 30, that overvoltage can be considered as a desired program voltage, and the editing mode of logic device is activated. In this case, the time delay of circuit 30 is determined by the strength of P channel transistor directly related with the turn-on resistance of P channel transistor and the size of capacitor.