Semiconductor memory device
View Patent ↗A semiconductor memory device processes external commands in parallel using divided clocks, which embodies a high-speed operation of a DRAM in increase of clock frequency. In the semiconductor memory device, command processing blocks are separated into row and column paths in parallel, and the command processing blocks connected in parallel are sequentially latched by clocks obtained by dividing input clocks applied externally, thereby improving the operation speed of the DRAM at high operation and reducing power consumption.
1. A semiconductor memory device comprising:
a clock generator for delaying an input clock for a predetermined time to generate a delay clock, and dividing the input clock to output a first division signal and a second division signal having an opposite phase to that of the first division signal;
a latch unit for latching an input signal buffered synchronously with respect to the delay clock for a predetermined time;
a first command processing means comprising a plurality of command processing blocks connected in parallel for latching and amplifying an output signal applied from the latch unit synchronously with respect to the first division signal and the second division signal;
a second command processing means comprising a plurality of bank control blocks connected in parallel for generating a control signal to control row and column paths in response to an output signal applied from the first command processing means synchronously with respect to the first division signal and the second division signal; and
a selection unit for selecting one of output signals from the second command processing means in response to the first division signal and the second division signal.
2. The semiconductor memory device according to claim 1 , further comprising:
an input buffer for comparing an input signal with a reference voltage to output the buffered input signal; and
a phase control unit for controlling phases of the first division signal and the second division signal to output a control signal for controlling the selection of the selection unit.
3. The semiconductor memory device according to claim 2 , wherein the phase control unit comprises:
a first delay unit for delaying the first division signal for a predetermined time;
a first AND gate for performing an AND operation on the first division signal and an output signal from the first delay unit;
a second delay unit for delaying the second division signal for a predetermined time;
a second AND gate for performing an AND operation on the second division signal and an output signal from the second delay unit; and
an OR gate for performing an OR operation on output signals from the first AND gate and the second AND gate.
4. The semiconductor memory device according to claim 1 , wherein the first command processing means comprises:
a first command processing block for latching and amplifying an output signal applied from the latch unit synchronously with respect to the first division signal to output a first output signal; and
a second command processing block for latching and amplifying an output signal applied from the latch unit synchronously with respect to the second division signal to output a second output signal.
5. The semiconductor memory device according to claim 4 , wherein the first command processing block receives the second output signal and the second command processing block receives the first output signal in order to operate only one of the first command processing block and the second processing block.
6. The semiconductor memory device according to claim 5 , wherein the first command processing block comprises a first latch amplification unit for latching and amplifying an output signal from the latch unit to disable the first output signal when the first division signal and the second output signal are all enabled.
7. The semiconductor memory device according to claim 6 , wherein the second command processing block comprises a second latch amplification unit for latching and amplifying an output signal from the latch unit to disable the second output signal when the second division signal and the first output signal are all enabled.
8. The semiconductor memory device according to claim 1 , wherein the second command processing means comprises:
a first bank control block for outputting a control signal to control row and column paths in response to an output signal from the first command processing means synchronously with respect to the first division signal; and
a second bank control block for outputting a control signal to control row and column paths in response to an output signal from the first command processing means synchronously with respect to the second division signal.
9. The semiconductor memory device according to claim 1 , wherein the clock generator comprises:
an amplifier for amplifying and buffering the input clock to output the delay clock;
a flip-flop unit for dividing the delay clock synchronously with respect to an output clock of the amplifier; and
a buffer unit for buffering an output signal from the flip-flop unit to output the first division signal and the second division signal.
10. The semiconductor memory device according to claim 1 , wherein the selection unit comprises:
a first selection unit for selecting a second output signal applied from the second command processing means in response to the first division signal and a first output signal from the second processing means; and
a second selection unit for selecting the first output signal applied from the second command processing means in response to the second division signal and a second output signal from the second command processing means.
11. The semiconductor memory device according to claim 10 , wherein the first selection unit comprises:
a first logic unit for performing a logic operation on the first division signal and the first output signal;
a first transmission gate for selectively controlling output of the second output signal depending on an output state of the first logic unit;
a first latch unit for latching an output signal from the first transmission gate; and
a second transmission gate for selectively controlling an output signal from the first latch unit depending on an output state of the first logic unit.
12. The semiconductor memory device according to claim 10 , wherein the second selection unit comprises:
a second logic unit for performing a logic operation on the second division signal and the second output signal;
a third transmission gate for selectively controlling output of the first output signal depending on an output state of the second logic unit;
a second latch unit for latching an output signal from the third transmission gate; and
a fourth transmission gate for selectively controlling an output signal from the second latch unit depending on an output state of the second logic unit.
13. The semiconductor memory device according to claim 1 , further comprising:
an asynchronous row control block for performing an asynchronous row command in response to an output signal from the selection unit; and
an asynchronous column control block for performing an asynchronous column command in response to an output signal from the selection unit.
14. A semiconductor memory device comprising:
a clock generator for delaying an input clock for a predetermined time to generate a delay clock, and dividing the input clock to output a first division signal and a second division signal having an opposite phase to that of the first division signal;
a latch unit for latching a input signal buffered synchronously with respect to the delay clock for a predetermined time;
a first command processing means for processing a predetermined operation command in response to an output signal applied from the latch unit synchronously with respect to the first division signal;
a second command processing means for processing a predetermined operation command in response to an output signal applied from the latch unit synchronously with respect to the second division signal; and
a selection unit for selecting one of output signals from the first command processing means and the second command processing means in response to the first division signal and the second division signal.
15. The semiconductor memory device according to claim 14 , wherein the first command processing means receives an output signal from the second command processing means and the second command processing means receives an output signal from the first command processing means in order to operate only one of the first command processing means and the second processing means.
16. The semiconductor memory device according to claim 14 , further comprising:
an input buffer for comparing an input signal with a reference voltage to output the buffered input signal having a full voltage level; and
a phase control unit for controlling phases of the first division signal and the second division signal to output a control signal for controlling selection of the selection unit.
17. The semiconductor memory device according to claim 14 , wherein the first command processing means comprises:
a first command processing block for latching and amplifying an output signal applied from the latch unit synchronously with respect to the first division signal; and
a first bank control block for outputting a bank control signal to control row and column paths in response to an output signal from the first command processing block synchronously with respect to the first division signal.
18. The semiconductor memory device according to claim 14 , wherein the second command processing means comprises:
a second command processing block for latching and amplifying an output signal applied from the latch unit synchronously with respect to the second division signal; and
a second bank control block for outputting a bank control signal to control row and column paths in response to an output signal from the second command processing block synchronously with respect to the second division signal.