Pseudo dual port memory devices
A pseudo dual port memory device in which an operating speed is improved and stability is increased is provided. The pseudo dual port memory device may include a memory cell, a pair of bit lines connected to the memory cell, a write driver, a sense amp, and a column multiplexer which is connected to the bit lines, receives a write multiplexer control signal and a read multiplexer control signal, connects the bit lines to the write driver in response to the write multiplexer control signal, and connects the bit lines to the sense amp in response to the read multiplexer control signal. A precharge control signal generation circuit which is connected to the column multiplexer may generate a precharge control signal on the basis of the read and write multiplexer control signals, and a bit line precharge circuit may precharge the bit lines based on the precharge control signal.
1 . A pseudo dual port memory device comprising:
a memory cell array which includes a plurality of word lines and memory cells connected to the plurality of word lines;
an address buffer configured to receive and buffer a read address signal and a write address signal;
a first word line decoder configured to decode the buffered read address signal and output a read word line enable signal;
a second word line decoder configured to decode the buffered write address signal and output a write word line enable signal;
a first word line driver configured to select one of the plurality of word lines and apply a first word line voltage, based on the read word line enable signal;
a second word line driver configured to select one of the plurality of word lines and apply a second word line voltage, based on the write word line enable signal;
a clock signal generator configured to generate an internal clock signal based on a system clock signal that has a clock cycle;
a word line predecoder configured to:
receive the internal clock signal, the buffered read address signal, and the buffered write address signal;
generate a read predeck signal based on the internal clock signal and the read address signal;
provide the read predeck signal to the first word line driver;
generate a write predeck signal based on the internal clock signal and the write address signal; and
provide the write predeck signal to the second word line driver; and
a NOR arithmetic element and an inverter connected to one of the first word line driver, the second word line driver, and the plurality of word lines,
wherein the first and second word line voltages are both applied during a single clock cycle,
wherein the first word line driver is configured to apply the first word line voltage through the NOR arithmetic element and the inverter based on the read word line enable signal and the read predeck signal, and
the second word line driver is configured to apply the second word line voltage through the NOR arithmetic element and the inverter based on the write word line enable signal and the write predeck signal.
2 . The pseudo dual port memory device of claim 1 , wherein the address buffer includes an address latch configured to buffer the read address signal, and an address flip-flop configured to buffer the write address signal.
3 . The pseudo dual port memory device of claim 1 , wherein the first word line decoder includes a first NAND logic element configured to perform an operation on the read address signal, and a first inverter, and
the second word line decoder includes a second NAND logic element configured to perform an operation on the write address signal, and a second inverter.
4 . The pseudo dual port memory device of claim 1 , further comprising:
an address clock signal, based on the system clock signal that has the clock cycle.
5 . The pseudo dual port memory device of claim 4 , wherein the address buffer includes an address latch configured to buffer the read address signal, and an address flip-flop configured to buffer the write address signal,
the address latch is configured to buffer the read address signal based on the address clock signal, and
the address flip-flop is configured to buffer the write address signal based on the address clock signal.
6 . The pseudo dual port memory device of claim 5 , wherein the address clock signal is logic low while a write operation is being performed.
7 . The pseudo dual port memory device of claim 1 , wherein the first word line decoder and the first word line driver are configured to operate during a first time interval, and
the second word line decoder and the second word line driver are configured to operate during a second time interval subsequent to the first time interval.
8 . The pseudo dual port memory device of claim 1 , wherein the first word line decoder is directly connected to the address buffer, the second word line decoder is directly connected to the address buffer, a first path between the first word line decoder and the address buffer does not include a switch, and a second path between the second word line decoder and the address buffer does not include a switch.
9 . A pseudo dual port memory device comprising:
a memory cell array which includes a plurality of word lines and memory cells connected to the plurality of word lines;
an address buffer configured to receive and buffer a read address signal and a write address signal;
a first word line decoder configured to decode the buffered read address signal and output a read word line enable signal;
a second word line decoder configured to decode the buffered write address signal and output a write word line enable signal;
a first word line driver configured to select one of the plurality of word lines and apply a first word line voltage, based on the read word line enable signal;
a second word line driver configured to select one of the plurality of word lines and apply a second word line voltage, based on the write word line enable signal;
a NOR arithmetic element having a first input connected to the first word line driver and a second input connected to the second word line driver; and
an inverter connected to the NOR arithmetic element and the plurality of word lines,
wherein the first and second word line voltages are both applied during a single clock cycle,
wherein the first word line driver is configured to apply the first word line voltage through the NOR arithmetic element and the inverter based on the read word line enable signal and a read predeck signal, and
the second word line driver is configured to apply the second word line voltage through the NOR arithmetic element and the inverter based on the write word line enable signal and a write predeck signal.
10 . The pseudo dual port memory device of claim 9 , wherein the address buffer includes an address latch configured to buffer the read address signal, and an address flip-flop configured to buffer the write address signal.
11 . The pseudo dual port memory device of claim 9 , wherein the first word line decoder includes a first NAND logic element configured to perform an operation on the read address signal, and a first inverter, and
the second word line decoder includes a second NAND logic element configured to perform an operation on the write address signal, and a second inverter.
12 . The pseudo dual port memory device of claim 9 , further comprising:
a clock signal generator configured to generate an internal clock signal and an address clock signal, based on a system clock signal that has a clock cycle; and
a word line predecoder configured to receive the internal clock signal, the buffered read address signal, and the buffered write address signal.
13 . The pseudo dual port memory device of claim 12 , wherein the word line predecoder is configured to generate the read predeck signal based on the internal clock signal and the read address signal and is configured to provide the read predeck signal to the first word line driver, and is further configured to generate the write predeck signal based on the internal clock signal and the write address signal and is configured to provide the write predeck signal to the second word line driver.
14 . The pseudo dual port memory device of claim 12 , wherein the address buffer includes an address latch configured to buffer the read address signal, and an address flip-flop configured to buffer the write address signal,
the address latch is configured to buffer the read address signal based on the address clock signal, and
the address flip-flop is configured to buffer the write address signal based on the address clock signal.
15 . The pseudo dual port memory device of claim 14 , wherein the address clock signal is logic low while a write operation is being performed.
16 . The pseudo dual port memory device of claim 9 , wherein the first word line decoder and the first word line driver are configured to operate during a first time interval, and
the second word line decoder and the second word line driver are configured to operate during a second time interval subsequent to the first time interval.
17 . The pseudo dual port memory device of claim 9 , wherein the first word line decoder is directly connected to the address buffer, the second word line decoder is directly connected to the address buffer, a first path between the first word line decoder and the address buffer does not include a switch, and a second path between the second word line decoder and the address buffer does not include a switch.
18 . A pseudo dual port memory device comprising:
a memory cell array which includes a plurality of word lines and memory cells connected to the plurality of word lines;
an address buffer configured to receive and buffer a read address signal and a write address signal;
a first word line decoder configured to decode the buffered read address signal and output a read word line enable signal;
a second word line decoder configured to decode the buffered write address signal and output a write word line enable signal;
a first word line driver configured to select one of the plurality of word lines and apply a first word line voltage, based on the read word line enable signal;
a second word line driver configured to select one of the plurality of word lines and apply a second word line voltage, based on the write word line enable signal;
a NOR arithmetic element having a first input connected to the first word line driver and a second input connected to the second word line driver; and
an inverter connected to the NOR arithmetic element and the plurality of word lines,
wherein the first and second word line voltages are both applied during a single clock cycle,
wherein the address buffer includes an address latch configured to buffer the read address signal, and an address flip-flop configured to buffer the write address signal,
wherein the address latch is directly connected to the first word line decoder and the address flip-flop is directly connected to the second word line decoder.