| 摘要 |
PURPOSE: A bit store circuit of a flash memory is provided to simplify circuits by using plural anti-fuses. CONSTITUTION: In an anti-fuse read of a bit store circuit of a flash memory, a reset signal(RESET) is a high level for a fixed time in an initial stage in order to reset an anti-fuse output signal(FUSE OUT), and an NMOS transistor(N6) is turned on, and the voltage of a node(A) is a ground level. When the reset signal(RESET) and an anti-fuse program signal(FPGM) are low signals, a PMOS transistor(P5) and a PMOS transistor(P7) are turned off, and the second NAND gate(L4) outputs a low signal, and an NMOS transistor(N5) and an NMOS transistor(N7) are turned off. And, because PMOS transistor(P6) is turned on, an anti-fuse program voltage(VFUSE) is applied to a node(A), and PMOS transistor(P8) are turned on, and an NMOS transistor(N8) is turned on. For this reason, a source voltage(Vcc) and the anti-fuse program voltage(VFUSE) are applied to two terminals of the first anti-fuse(AF1), and the anti-fuse program voltage(VFUSE) and a ground voltage are applied to two terminals of the second anti-fuse(AF2). If the first anti-fuse(AF1) is programmed, an output(FUSE OUT) is a low signal. If the second anti-fuse(AF2) is programmed, an output(FUSE OUT) is a high signal. In conclusion, when a power is inputted, the output(FUSE OUT) is decided according to a state of each anti-fuse without a specific circuit.
|
