Patent ID: 6462608
Filing Date: 2002-10-08
Classification: G11C

Abstract:
A programmable circuit coupled to a first power supply and a second power supply for providing a programmed signal in an integrated circuit, comprising:a first node, wherein the state of the programmed signal is based on the state of the first node; a first anti-fuse having a programmed state and an unprogrammed state and coupling the first node to the first power supply when in the programmed state and decoupling the first node from the first power supply when in the unprogrammed state, wherein the first anti-fuse has a first terminal coupled to the first node and a second terminal; a second anti-fuse having a programmed state and an unprogrammed state and coupling the first node to the second power supply when in the programmed state and decoupling the first node from the second power supply when in the unprogrammed state, wherein the second anti-fuse has a first terminal coupled to the first node and a second terminal; a first programming bus carrying a sufficient voltage to short the first anti-fuse; a first switch coupled to the second terminal of the first anti-fuse for coupling the second terminal of the first anti-fuse to the first power supply during normal operation of the integrated circuit and coupling the second terminal of the first anti-fuse to the first programing bus during a first programming operation of the integrated circuit for programming the first anti-fuse; a second programming bus carrying a sufficient voltage to short the second anti-fuse; a second switch coupled to the second terminal of the second anti-fuse for coupling the second terminal of the second anti-fuse to the second power supply during normal operation of the integrated circuit and coupling the second terminal of the second anti-fuse to the second programing bus during a second programming operation of the integrated circuit for programming the second anti-fuse; and a third switch coupled between the second power supply and the first node and responsive to a plurality of programming control signals, wherein the third switch is closed to couple the first node to the second power supply during a programming operation of the integrated circuit and open during normal operations of the integrated circuit.