JPS6479997A - P-rom - Google Patents

Abstract

PURPOSE:To optimize the characteristics and circuit constant of respective transistors (TR) in accordance with respective absorption current by providing, at a word wire, the TR for writing current absorption, in which the base current is controlled according to the conversion of the potential of the word wire to the prescribed potential. CONSTITUTION:A buffer TR 2 is turned on in accordance with an input address through a word driver 1, the corresponding word wire is selected, and made into the prescribed potential. Thus, into a memory cell 3 of a P-ROM connected to the selected word wire, the writing current through a writing means 4 is supplied, and the condition of the cell 3 is irreversibly changed. At the time of the writing, a TR 5 for writing current absorption to be connected with the selected word wire is turned on through a base current supplying means 6, and the writing current is absorbed. On the other hand, the reading current is absorbed by the TR 2, writing and reading currents are absorbed by the different TRs, and the respective TRs and the circuit constant can be optimized. Consequently, the switching speed can be raised at the time of the reading, and energy consumption can be reduced.