Redundancy selector circuit for use in non-volatile memory device
View Patent ↗A redundancy selector circuit for use in a non-volatile memory device include a ROM cell array, in which defective addresses are stored, including a plurality of ROM cells arranged in a matrix of rows and columns; a ROM controller for sequentially selecting rows of the ROM cell array at power-up; a sense amplifier block for sensing and amplifying data bits from ROM cells of the respective rows selected sequentially according to the control of the ROM controller; a latch block for receiving data bits sensed by the sense amplifier block through a switch circuit and latching the input data bits as a defective address; and a comparator block for detecting whether an address input in a normal operation matches one of the defective addresses stored in the latch block. As the rows are sequentially selected, the defective addresses of the ROM cell array are transferred to the latch block through the sense amplifier block by means of serial transfer.
1. A redundancy selector circuit for use in a flash memory device, the redundancy selector circuit comprising:
a ROM cell array that includes a plurality of ROM cells arranged in a matrix of rows and columns for storing defective addresses of the flash memory device;
a ROM controller for sequentially selecting rows of the ROM cell array at power-up;
a sense amplifier block for sensing data bits from ROM cells selected by the ROM controller, wherein the data bits represent one or more defective addresses of the flash memory device;
a latch block for serially receiving the defective address data bits sensed by the sense amplifier block through a switch circuit, and subsequently latching the serially input defective address data bits; and
a comparator block for detecting whether an address input in a normal operation of the flash memory device matches one of the one or more defective addresses stored in the latch block.
2. The redundancy selector circuit of claim 1 , wherein the number of the rows of the ROM cell array is equal to that of a number of redundant columns provided to the flash memory device.
3. The redundancy selector circuit of claim 2 , wherein the number of the columns of the ROM cell array is equal to that of the number of bits of an address for addressing a defective column.
4. The redundancy selector circuit of claim 1 , wherein each of the ROM cells comprises:
a fuse;
a transistor having a gate connected to a corresponding row;
a drain connected to a corresponding column; and
a source grounded through the fuse.
5. The redundancy selector circuit of claim 1 , wherein the ROM cell array further comprises a PMOS transistor coupled between one end of each respective columns and a power supply voltage, the PMOS transistor being controlled by the ROM controller to precharge the columns at power-up.
6. A redundancy selector circuit for use in a non-volatile memory device, the redundancy selector circuit comprising:
a ROM cell array that includes a plurality of ROM cells arranged in a matrix of rows and columns for storing defective addresses of the non-volatile memory device;
a ROM controller for sequentially selecting rows of the ROM cell array at power-up;
a sense amplifier block for sensing data bits from ROM cells selected by the ROM controller, wherein the data bits represent one or more defective addresses of the non-volatile memory device;
a latch block for receiving the defective address data bits sensed by the sense amplifier block through a switch circuit, and subsequently latching the input defective address data bits; and
a comparator block for detecting whether an address input in a normal operation of the non-volatile memory device matches one of the one or more defective addresses stored in the latch block.
7. The redundancy selector circuit of claim 6 , wherein as the rows are sequentially selected, the defective addresses of the ROM cell array are transferred to the latch block through the sense amplifier block by means of serial transfer.