JPS6448298A - Rom circuit - Google Patents

Abstract

PURPOSE:To obtain a low energy consumption ROM circuit by constituting the circuit of a P-shaped MOS transistor (TR) whose respective sources are connected to a voltage source, an N-shaped MOS transistor whose source is connected to a ground and an N-number of the N-shaped MOS TRs. CONSTITUTION:The titled circuit is composed of first and second TRs of a first polarity of which the respective source are connected to the first voltage source, a third TR of a second polarity whose source is connected to a second voltage source and the N-number of the TRs. The gate of the first TR is connected to the drain of the second TR and the gate of the second TR is connected to the drain of the first TR. Then, the gate of the third transistor is connected to a first control input terminal. The drain is connected to the drain of the first TR and the gates of the N-number of TRs of the second polarity are respectively connected to the N-number of input terminals. Then, the writing of the ROM is executed separately when the respective drains of the N-number TRs are connected to the drain of the second TR and when they are not connected. Thus, the ROM circuit of the low energy consumption can be realized.