| 摘要 |
PURPOSE:To easily alter the driving ability of an output buffer by connecting the input of either of two logical gates to the connection node of an internal circuit and the output to an external terminal, and connecting the control input of a control circuit to an external connection terminal. CONSTITUTION:Outputs of output buffers 7 and 9 are connected directly to external outputs J and K and also connected to an output buffer 8 through transfer gates 15 and 17, and inputs are connected to connection points I and K of the internal circuit and also connected to output buffers 14 and 16 respectively. Control terminals of the gates 14 and 15, on the other hand, are connected to an external control terminal M and control terminals of gates 16 and 17 are connected directly to the external control terminal M. Here, when the gates 14 and 15 are opened with the control signal from the terminal M, the gates 16 and 17 are closed. Further, when the opposite control signal is applied to the terminal M, the gates 14 and 15 are closed and the gates 16 and 17 are opened. For the purpose, the control signal supplied to the terminal M is controlled from outside to increase the driving output of either of terminals J and K. |
