HYBRID INTEGRATED CIRCUIT DEVICE

摘要

PROBLEM TO BE SOLVED: To make it possible to write a program after mounting a mixture integrated circuit and to unnecessitate an external terminal for supplying voltage for writing. SOLUTION: A microcomputer IC 3 incorporating an EPROM 2 is formed on a substrate 1, further a pad 4 for supplying voltage for writing and a voltage supplying circuit 100 for supplying power voltage VPP and VDD to the microcomputer IC 3 is formed. The voltage supplying circuit 100 has first and second transistors 5, 6, when high voltage for writing is applied to the pad 4, the first transistor 5 is turned on, the second transistor 6 is turned off, and voltage for writing is supplied to the EPROM 2. When a program is read out after packaging, since no voltage is applied to the pad 4, the first transistor 5 is turned off, the second transistor 6 turned on, operation voltage VDD is supplied to the EPROM 2 from an external terminal A, and a program can be read out.