Delay circuit using current source

摘要

A delay circuit having a constant period of delay time independent of changes in operations, temperature and voltage includes a current source for generating a constant current and having PMOS transistors of which gates are commonly connected, wherein the constant current is controlled by sizes of the PMOS transistors; and a unit delay circuit including a CMOS inverter having PMOS and NMOS transistors, wherein non-adjacent PMOS and NMOS transistors are controlled to charge and discharge current when a constant level of the constant current is transmitted from the current source and other adjacent PMOS and NMOS transistors are switched to connect or disconnect a current path through which the current is charged or discharged.