Output buffer having a plurality of switching devices being turned on successively at shorter time intervals to achieve increasing drive capability using a predriver

摘要

An output drive circuit of an output buffer circuit has a signal output line and first, second and third switching circuits connected to the signal output line at different locations thereof. Each of the first, second and third switching circuits includes one of first switching devices connected between a power source line and the signal output line, and one of second switching devices connected between the signal output line and a ground line. Each of the first, second and third switching circuits includes one of first control signal lines that turn on and off the first switching devices, respectively, and one of second control signal lines that turn on and off the second switching devices, respectively. Drivabilities of the first and/or the second switching devices in the switching circuits are set to gradually increase in a specified order.