Semiconductor memory devices and electronic devices including the semiconductor memory devices
A semiconductor memory device includes a data input/output (I/O) buffer, a data first-in/first-out (FIFO) circuit, an address comparing circuit. The data I/O buffer provides a memory cell array with write data. The data FIFO circuit includes plurality of data FIFO buffers which store read data that is read from the memory cell array in each of a plurality of read operations. The data FIFO circuit outputs data stored in one of the plurality of data FIFO buffers based on a plurality of sub matching signals. The address comparing circuit sequentially stores previous addresses accompanied by first commands designating the plurality of read operations and generates the plurality of sub matching signals based on a comparison of the previous addresses and a present address accompanied by a second command designating a present read operation.
1 . An electronic device comprising:
a system-on-chip (SoC) including a memory controller, a display controller, and a graphic processing unit (GPU) configured to generate a plurality of image data by rendering at least one object;
a semiconductor memory device connected to the SoC through the memory controller; and
a display device connected to the SoC through the display controller,
wherein the semiconductor memory device comprises:
a memory cell array including a plurality of volatile memory cells coupled to a plurality of word-lines and a plurality of bit-lines, the memory cell array configured to store the plurality of image data; and
a data first-in/first-out (FIFO) circuit including a plurality of data FIFO buffers configured to sequentially store read image data that is read from the memory cell array in each of a plurality of read operations, and
wherein, when a second frame to be displayed in the display device comprises first image data that is the same image data as is in one of a predetermined range of previous first frames, the semiconductor memory device is configured to provide, via the memory controller and the display controller, the display device with the first image data from one of the plurality of data FIFO buffers.
2 . The electronic device of claim 1 , wherein the semiconductor memory device further includes:
a data input/output (I/O) buffer configured to provide the memory cell array with the plurality of image data received from the memory controller in each of a plurality of write operations;
an address comparing circuit configured to store sequentially a plurality of previous addresses accompanied by first commands designating the plurality of read operations, and configured to generate a plurality of sub matching signals based on a comparison of the previous addresses with a present address accompanied by a second command designating a present read operation; and
a control logic circuit configured to receive the first commands and the second command from the memory controller and configured to provide a read signal to the address comparing circuit in response to the first commands and the second command designating the plurality of read operations and the present read operation.
3 . The electronic device of claim 2 , wherein the semiconductor memory device further includes:
a first switch connected between an address buffer configured to receive the previous addresses and the present address and a column decoder coupled to the plurality of bit-lines; and
a second switch connected between the data FIFO circuit and an I/O gating circuit connected to the memory cell array, and
wherein the address comparing circuit includes:
a plurality of address FIFO buffers configured to store a plurality of addresses accompanied by the plurality of read operations;
a plurality of address comparators each configured to compare the present address with a respective one of the plurality of previous addresses stored in the plurality of address FIFO buffers and generate a sub matching signal, resulting in the plurality of sub matching signals;
an OR gate configured to perform an OR operation on the plurality of sub matching signals and generate a matching signal;
an inverter configured to invert the matching signal and generate a no matching signal;
an updating signal generator configured to generate an updating signal based on the no matching signal and the read signal; and
a switching signal generator configured to generate a switching control signal that is applied to the first switch and the second switch, based on the matching signal.
4 . The electronic device of claim 3 , wherein, in response to one of the plurality of sub matching signals indicating that the present address matches one of the plurality of previous addresses,
the switching signal generator is configured to turn off the first switch and the second switch by applying a switching control signal to the first switch and the second switch.
5 . The electronic device of claim 3 , wherein, in response to the no matching signal indicating that the present address does not match respective one of the plurality of previous addresses,
the plurality of data FIFO buffers are configured to store image data associated with the present address in a FIFO manner.