Semiconductor memory device
View Patent ↗The present invention provides a semiconductor memory device adjusting a bit line over driving period according to a power supply voltage level. A semiconductor memory device for stabilizing a bit line sense amplifier (hereinafter, referred as BLSA) includes the BLSA operated by a sense amplifier driving voltage; and a controller for comparing a feedbacked sense amplifier driving voltage with a reference voltage to thereby control the sense amplifier driving voltage to the BLSA.
1. A semiconductor memory device for stabilizing a bit line sense amplifier (BLSA), comprising:
a blind delay unit for delaying a BLSA enable signal for a predetermined time to thereby output a detection signal;
a sensing unit for comparing a reference voltage and a feedbacked sense amplifier driving voltage to thereby output an over driving off signal in response to the detection signal;
a drive control signal generating unit for generating a first and a second drive control signal in response to the BLSA enable signal and the over driving off signal;
a drive circuit for driving a BLSA pull up power supply line in response to the first and the second drive control signals; and
a feedback circuit for receiving a voltage of the BLSA pull up power supply line to thereby generate the feedbacked sense amplifier driving voltage.
2. The semiconductor memory device as recited in claim 1 , wherein the BLSA pull up power supply line is driven by of a normal driving voltage and an over driving voltage selected in response to the first and the second drive control signals.
3. The semiconductor memory device as recited in claim 2 , wherein the drive circuit includes:
a first driver for driving the BLSA pull up power supply line with the over driving voltage in response to the first drive control signal; and
a second driver for driving the BLSA pull up power supply line into the normal driving voltage in response to the second drive control signal.
4. The semiconductor memory device as recited in claim 3 , wherein the normal driving voltage is a core voltage; and the over driving voltage is a power supply voltage.
5. The semiconductor memory device as recited in claim 4 , wherein the first driver is a first NMOS transistor, the first NMOS transistor connected between the power supply voltage and the BLSA pull up power supply line and receiving the first drive control signal through a gate thereof.
6. The semiconductor memory device as recited in claim 5 , wherein the second driver is a second NMOS transistor connected between the core voltage and the BLSA pull up power supply line and receiving the second drive control signal through a gate thereof.
7. The semiconductor memory device as recited in claim 4 , wherein the sensor includes a differential amplifier receiving the reference voltage and the feedbacked sense amplifier driving voltage, the differential amplifier enabled in response to the detection signal.
8. The semiconductor memory device as recited in claim 7 , wherein the feedback circuit includes a bit line model circuit for reflecting a bit line parasitic element to the voltage of the BLSA pull up power supply line.
9. The semiconductor memory device as recited in claim 8 , wherein the reference voltage is the core voltage.
10. The semiconductor memory device as recited in claim 9 , wherein the bit line model circuit includes:
a RC replica formed with a resistor and a capacitor, the RC replica for modeling the bit line parasitic element;
a MOS transistor for driving the RC replica by using the voltage of the BLSA pull up power supply line in response to the BSLA enable signal.
11. The semiconductor memory device as recited in claim 8 , wherein the feedback circuit further includes a voltage divider for dividing an output voltage of the bit line model circuit to thereby output the feedback voltage.
12. The semiconductor memory device as recited in claim 11 , wherein a level of the reference voltage has a half level of the core voltage.
13. The semiconductor memory device as recited in claim 12 , wherein the voltage divider is provided with a first and a second resistors serially connected each other, the first and the second resistors having the same resistance and being implemented with a MOS transistor respectively.
14. The semiconductor memory device as recited in claim 4 , wherein the blind delay includes:
a delay receiving the BLSA enable signal;
a NAND gate receiving an output of the delay and BLSA enable signal; and
an inverter receiving an output of the NAND gate.
15. The semiconductor memory device as recited in claim 4 , wherein the drive control signal generator includes:
a first AND gate for logically multiplying the BLSA enable signal and the over driving off signal; and
a second AND gate for logically multiplying the BLSA enable signal and an output of the first AND gate.
16. The semiconductor memory device as recited in claim 4 , wherein the drive control signal generator includes:
a first inverter receiving the BLSA enable signal;
a second inverter receiving an output from the first inverter;
a third inverter receiving the over driving off signal;
a first NAND gate receiving an output of the third inverter and BLSA enable signal;
a second NAND gate receiving an output of the first NAND gate and second inverters;
a fourth inverter receiving an output of the second NAND gate;
a fifth inverter receiving the output of the first NAND gate;
a first buffer for buffering an output of the fourth inverter to thereby output the second drive control signal; and
a second buffer for buffering an output of the fifth inverter to thereby output the first drive control signal.
17. Methed A method for stably supplying a driving voltage to a bit line sense amplifier (BLSA), comprising:
delaying a BLSA enable signal for a predetermined fixed timing to thereby output a detection signal;
comparing a feedbacked sense amplifier driving voltage with a reference voltage to thereby output an over driving off signal in response to the detection signal;
generating a first and a second drive control signals in response to the BLSA enable signal and the over driving off signal, respectively;
driving a BLSA pull up power supply line in response to the first and the second drive control signals;
operating the BLSA by driving the BLSA pull up power supply line; and
receiving a voltage of the BLSA pull up power supply line to generating the feedback sense amplifier driving voltage.
18. The method as recited in claim 17 , wherein the BLSA pull up power supply line is driven by one of a normal driving voltage and an over driving voltage selected by the first and the second drive control signals.