Semiconductor device having sense amplifier
View Patent ↗A semiconductor device includes a first driver circuit for supplying a first potential to a first power supply node of the sense amplifier, second and third driver circuits for supplying a second potential and a third potential to a second power supply node of the sense amplifier, and a timing control circuit for controlling operations of the first to third driver circuits. The timing control circuit includes a delay circuit for deciding an ON period of the third driver circuit. The delay circuit includes a first delay circuit having a delay amount that depends on an external power supply potential and a second delay circuit having a delay amount that does not depend on the external power supply potential, and the ON period of the third driver circuit is decided based on a sum of the delay amounts of the first and second delay circuits.
1. A semiconductor device comprising:
a pair of bit lines;
a sense amplifier having first and second power supply nodes, the sense amplifier connecting one of the pair of bit lines to the first power supply node and connecting the other of the pair of bit lines to the second power supply node based on a potential difference between the pair of bit lines;
a first driver circuit supplying a first potential to the first power supply node of the sense amplifier;
a second driver circuit supplying a second potential to the second power supply node of the sense amplifier;
a third driver circuit supplying a third potential to the second power supply node of the sense amplifier; and
a timing control circuit controlling operations of the first to third driver circuits, wherein
a potential difference between the first potential and the third potential is larger than a potential difference between the first potential and the second potential,
the timing control circuit turns the first and third driver circuits ON and then turns the third driver circuit OFF and turns the second driver circuit ON,
the timing control circuit includes a plurality of delay circuits that decide an ON period of the third driver circuit,
the delay circuits include a first delay circuit having a delay amount that depends on an external power supply potential supplied from outside and a second delay circuit having a delay amount that does not depend on the external power supply potential, and
the ON period of the third driver circuit is decided based on a sum of the delay amounts of the first and second delay circuits.
2. The semiconductor device as claimed in claim 1 , further comprising a power supply circuit generating a stabilized internal power supply potential based on the external power supply potential,
wherein the delay amount of the second delay circuit depends on the internal power supply potential.
3. The semiconductor device as claimed in claim 2 , wherein
the power supply circuit further generates the third potential based on the external power supply potential, and
the power supply circuit includes a limit circuit limiting the third potential when a level of the external power supply potential is equal to or more than a predetermined value.
4. The semiconductor device as claimed in claim 3 , wherein the limit circuit matches the third potential with the level of the external power supply potential when the level of the external power supply potential is less than the predetermined value, and fixes the third potential at the predetermined value when the level of the external power supply potential is equal to or more than the predetermined value.
5. A semiconductor device comprising:
a pair of bit lines;
an amplifier circuit amplifying a potential difference between the pair of bit lines;
a power supply circuit generating first and second power supply voltages based on an external power supply voltage supplied from outside;
a first node to which the first power supply voltage is supplied;
a second node to which a third power supply voltage higher than the first power supply voltage is supplied;
a first transistor connected between the first node and the amplifier circuit;
a second transistor connected between the second node and the amplifier circuit; and
a control circuit supplying first and second control signals to the first and second transistors, respectively, in response to a first signal, the control circuit including a first delay circuit operating on the external power supply voltage and a second delay circuit connected in series to the first delay circuit and operating on the second power supply voltage, and delaying the first signal by the first and second delay circuits to generate the first and second control signals.
6. The semiconductor device as claimed in claim 5 , wherein the control circuit drives the second control signal from an inactive level to an active level to change the second transistor from an OFF state to an ON state, and then drives the second control signal from the activate level to the inactive level to change the second transistor from the ON state to the OFF state and drives the first control signal from an inactive level to an active level to change the first transistor from an OFF state to an ON state.
7. The semiconductor device as claimed in claim 6 , wherein the first and second delay circuits control a timing at which the first control signal transits from the inactive level to the active level and a timing at which the second control signal transits from the active level to the inactive level.
8. The semiconductor device as claimed in claim 7 , wherein the first and second power supply voltages are at substantially constant potential levels irrespective of a potential level of the external power supply voltage both when the external power supply voltage is at a first potential level and when the external power supply voltage is at a second potential level higher than the first potential level.
9. The semiconductor device as claimed in claim 5 , wherein the power supply circuit further generates the third power supply voltage based on the external power supply voltage.
10. The semiconductor device as claimed in claim 9 , wherein
the power supply circuit includes a limit circuit receiving the external power supply voltage to generate the third power supply voltage, and
the limit circuit changes a potential level of the third power supply voltage depending on the potential level of the external power supply voltage when the potential level of the external power supply voltage is lower than a first potential level, and controls the potential level of the third power supply voltage to the substantially constant first potential level irrespective of the potential level of the external power supply voltage when the potential level of the external power supply voltage is higher than the first potential level.
11. The semiconductor device as claimed in claim 5 , wherein the first transistor has a first conductivity type and the second transistor has a second conductivity type different from the first conductivity type.
12. The semiconductor device as claimed in claim 5 , wherein a potential level of the first power supply voltage is substantially the same as that of the second power supply voltage.