Read latency reduction in a memory device
View Patent ↗A memory device can include: a memory array with memory cells arranged as data lines; an interface that receives a read command requesting bytes of data in a consecutively addressed order from an address of a starting byte; a first buffer that stores a first data line from the memory array that includes the starting byte; a second buffer that stores a second data line from the memory array, which is consecutively addressed with respect to the first data line; output circuitry configured to access data from the buffers, and to sequentially output each byte from the starting byte through a highest addressed byte of the first data line, and each byte from a lowest addressed byte of the second data line until the requested data bytes has been output; and a data strobe driver that clocks each byte of data output by a data strobe on the interface.
1. A memory device, comprising:
a) a memory array comprising a plurality of memory cells arranged as a plurality of data lines, wherein each data line comprises a predetermined number of bytes of data;
b) an interface configured to receive a read command from a host that requests a plurality of bytes of data in a consecutively addressed order from an address of a starting byte;
c) a first buffer configured to store a first of the plurality of data lines from the memory array, wherein the first data line comprises the starting byte;
d) a second buffer configured to store a second of the plurality of data lines from the memory array, wherein the second data line is consecutively addressed with respect to the first data line;
e) output circuitry configured to access data from the first buffer, and to sequentially output each byte from the starting byte through a highest addressed byte of the first data line;
f) the output circuitry being configured to access data from the second buffer, and to sequentially output each byte from a lowest addressed byte of the second data line until the requested plurality of bytes of data has been output in order to execute the read command; and
g) a data strobe driver configured to clock each byte of data output from the memory device by a data strobe on the interface, wherein the data strobe is activated at a reduced read latency in response to the first buffer receiving the first data line, and wherein the second buffer receives the second data line prior to the data output from the first buffer being completed.
2. The memory device of claim 1 , wherein the predetermined number of bytes of data in each data line is 16 bytes.
3. The memory device of claim 1 , further comprising a plurality of sense amplifiers activated to read the predetermined number of bytes of data.
4. The memory device of claim 1 , wherein:
a) the memory array comprises non-volatile memory; and
b) the interface comprises a serial interface.
5. The memory device of claim 1 , wherein the interface is configured to output a byte of data for each transition of the data strobe.
6. The memory device of claim 1 , wherein the rate of transferring data from the memory array to the first and second buffers is equal or larger than the maximum rate of transferring data from the first and second buffers to the host, and wherein the time to fill the second buffer with new data from the memory array is equal or smaller than the time required to send the remaining bytes in the first buffer to the host.
7. A memory device, comprising:
a) a memory array comprising a plurality of memory cells arranged as a plurality of data lines, wherein each data line comprises a predetermined number of bytes of data, and wherein the memory array comprises first and second array planes;
b) an interface configured to receive a read command from a host that requests a plurality of bytes of data in a consecutively addressed order from an address of a starting byte;
c) a first buffer configured to store a first of the plurality of data lines read from the first array plane of the memory array, wherein the first data line comprises the starting byte;
d) a second buffer configured to store a second of the plurality of data lines read from the second array plane of the memory array, wherein the second data line is consecutively addressed with respect to the first data line;
e) output circuitry configured to access data from the first buffer, and to sequentially output each byte from the starting byte through a highest addressed byte of the first data line, wherein the output circuitry is configured to output data in response to the first buffer receiving the first data line from the memory array; and
f) the output circuitry being configured to access data from the second buffer, and to sequentially output each byte from a lowest addressed byte of the second data line until the predetermined number of bytes of data has been output in order to execute the read command, wherein the second buffer receives the second data line prior to the data output from the first buffer being completed.
8. The memory device of claim 7 , wherein the predetermined number of bytes of data in each data line is 16 bytes.
9. The memory device of claim 7 , further comprising a plurality of sense amplifiers activated to read the predetermined number of bytes of data from the memory array.
10. The memory device of claim 7 , wherein the rate of transferring data from the memory array to the first and second buffers is equal or larger than the maximum rate of transferring data from the first and second buffers to the host, and wherein the time to fill the second buffer with new data from the memory array is equal or smaller than the time required to send the remaining bytes in the first buffer to the host.
11. The memory device of claim 7 , wherein the first and second data lines are accessed fully in parallel from the first and second array planes.
12. The memory device of claim 7 , wherein the first and second data lines are accessed at least partially in parallel from the first and second array planes.
13. The memory device of claim 7 , wherein the first and second data lines are accessed sequentially from the first and second array planes.
14. A memory device, comprising:
a) a memory array comprising a plurality of memory cells arranged as a plurality of data lines, wherein each data line comprises a predetermined number of bytes of data, and wherein the memory array comprises first and second word lines;
b) an interface configured to receive a read command from a host that requests a plurality of bytes of data in a consecutively addressed order from an address of a starting byte;
c) a first buffer configured to store a first of the plurality of data lines from along the first word line of the memory array, wherein the first data line comprises the starting byte;
d) a second buffer configured to store a second of the plurality of data lines from along the first word line of the memory array, wherein the second data line is consecutively addressed with respect to the first data line, and wherein the second data line is duplicated along the second word line of the memory array;
e) output circuitry configured to access data from the first buffer, and to sequentially output each byte from the starting byte through a highest addressed byte of the first data line; and
f) the output circuitry being configured to access data from the second buffer, and to sequentially output each byte from a lowest addressed byte of the second data line until the predetermined number of bytes of data has been output in order to execute the read command.
15. The memory device of claim 14 , wherein the predetermined number of bytes of data in each data line is 16 bytes.
16. The memory device of claim 14 , wherein:
a) the memory array comprises non-volatile memory; and
b) the interface comprises a serial interface.
17. The memory device of claim 14 , further comprising a plurality of sense amplifiers activated to read the first data line.
18. The memory device of claim 14 , further comprising a plurality of sense amplifiers activated to read the second data line.
19. The memory device of claim 14 , wherein the duplicated second data line is the lowest addressed data line along the second word line of the memory array.
20. The memory device of claim 14 , wherein the duplicated second data line is the highest addressed data line along the first word line of the memory array.