Dense Multi-Port Cell Scheme
Original Publication Date: 1987-Dec-01
Included in the Prior Art Database: 2005-Feb-02
A multi-port cell scheme is described which avoids simultaneous addressing if two or several port addresses access the same cell. For this purpose, read addresses A and B are fed to a compare means (Fig. 1) which supplies an inhibit signal in response to a match. The inhibit signal is used to deactivate the decoder for port B. This ensures that upon the occurrence of a common address at both inputs, only port A is selected. Such a circuit is easy to implement in an array, as generally there is an adequate number of redundant circuits that are suitable for this purpose, and each array word line is capable of being deactivated. Signals A INT and B INT are generated by the sense amplifier of each port. These signals are fed to a circuit (Fig. 2). Signal A INT is amplified directly to port A.