Lookup table and programmable logic device including lookup table
View Patent ↗A lookup table with low power consumption is provided. The lookup table includes a memory element including a transistor and a capacitor. A drain of the transistor is connected to one electrode of a capacitor and the input of an inverter, and a source is connected to a first wiring. The other electrode of the capacitor is connected to a second wiring. In such a memory element, the potential of the second wiring is complementary to the potential of the first wiring when writing data; accordingly, the potential of the drain of the transistor, i.e., the potential of the input of the inverter can be higher than the high potential of the inverter. Thus, shoot-through current of the inverter at this time can be significantly reduced. As a result, power consumption in a standby state can be significantly reduced.
1. A lookup table comprising:
a memory including a first memory element and a second memory element; and
multiplexers electrically connected to each other in a binary tree with multi levels, the multiplexers including a first multiplexer in the lowermost level of the multi levels,
wherein a first input terminal of the first multiplexer is electrically connected to the first memory element,
wherein a second input terminal of the first multiplexer is electrically connecter to the second memory element,
wherein each of the first memory element and the second memory element comprises:
a first transistor whose off-state current per 1 μm of a channel width is 100 zA or less;
an n-channel transistor;
a p-channel transistor;
a capacitor;
an input terminal;
an output terminal; and
a terminal,
wherein one of a source and a drain of the first transistor is electrically connected to one of electrodes of the capacitor, a gate of the n-channel transistor, and a gate of the p-channel transistor,
wherein the other of the electrodes of the capacitor is electrically connected to the terminal,
wherein one of a source and a drain of the n-channel transistor is electrically connected to one of a source and a drain of the p-channel transistor,
wherein the input terminal is electrically connected to the other of the source and the drain of the p-channel transistor, and
wherein the output terminal is electrically connected to the one of the source and the drain of the n-channel transistor and the one of the source and the drain of the p-channel transistor.
2. The lookup table according to claim 1 , wherein a channel length of the n-channel transistor is twice or more a channel length of the p-channel transistor.
3. The lookup table according to claim 1 , further comprising an inverter electrically connected to an output terminal of one of the multiplexers in a level other than the lowermost level.
4. A programmable logic device comprising the lookup table according to claim 1 .
5. A lookup table comprising:
memory elements; and
first multiplexers each including a first input terminal and a second input terminal,
wherein the first multiplexers are electrically connected to each other in a binary tree with multi levels,
wherein the first multiplexers include second multiplexers in the lowermost level of the multi levels,
wherein each of the first input terminals and the second input terminals of the second multiplexers are electrically connected to respective memory elements,
wherein the memory elements each comprises:
a first transistor whose off-state current per 1 μm of a channel width is 100 zA or less;
an n-channel transistor;
a p-channel transistor;
a capacitor;
an input terminal;
an output terminal; and
a terminal,
wherein one of a source and a drain of the first transistor is electrically connected to one of electrodes of the capacitor, a gate of the n-channel transistor, and a gate of the p-channel transistor,
wherein the other of the electrodes of the capacitor is electrically connected to the terminal,
wherein one of a source and a drain of the n-channel transistor is electrically connected to one of a source and a drain of the p-channel transistor,
wherein the input terminal is electrically connected to the other of the source and the drain of the p-channel transistor, and
wherein the output terminal is electrically connected to the one of the source and the drain of the n-channel transistor and the one of the source and the drain of the p-channel transistor.
6. The lookup table according to claim 5 , wherein a channel length of the n-channel transistor is twice or more a channel length of the p-channel transistor.
7. The lookup table according to claim 5 , further comprising a second memory element electrically connected to one of the first multiplexers in a level other than the lowermost level.
8. The lookup table according to claim 5 , further comprising an inverter electrically connected to an output terminal of one of the first multiplexers in a level other than the lowermost level.
9. A programmable logic device comprising the lookup table according to claim 5 .
10. A lookup table comprising:
a memory including a first memory element and a second memory element; and
multiplexers electrically connected to each other in a binary tree with multi levels, the multiplexers including a first multiplexer in the lowermost level of the multi levels,
wherein a first input terminal of the first multiplexer is electrically connected to the first memory element,
wherein a second input terminal of the first multiplexer is electrically connecter to the second memory element,
wherein each of the first memory element and the second memory element comprises:
a first transistor;
an n-channel transistor;
a p-channel transistor;
a capacitor;
an input terminal;
an output terminal; and
a terminal,
wherein one of a source and a drain of the first transistor is electrically connected to one of electrodes of the capacitor, a gate of the n-channel transistor, and a gate of the p-channel transistor,
wherein the other of the electrodes of the capacitor is electrically connected to the terminal,
wherein one of a source and a drain of the n-channel transistor is electrically connected to one of a source and a drain of the p-channel transistor,
wherein the input terminal is electrically connected to the other of the source and the drain of the p-channel transistor, and
wherein the output terminal is electrically connected to the one of the source and the drain of the n-channel transistor and the one of the source and the drain of the p-channel transistor.
11. The lookup table according to claim 10 , wherein a channel length of the n-channel transistor is twice or more a channel length of the p-channel transistor.
12. The lookup table according to claim 10 , further comprising an inverter electrically connected to an output terminal of one of the multiplexers in a level other than the lowermost level.
13. A programmable logic device comprising the lookup table according to claim 10 .
14. A lookup table comprising:
memory elements; and
first multiplexers each including a first input terminal and a second input terminal,
wherein the first multiplexers are electrically connected to each other in a binary tree with multi levels,
wherein the first multiplexers include second multiplexers in the lowermost level of the multi levels,
wherein each of the first input terminals and the second input terminals of the second multiplexers are electrically connected to respective memory elements,
wherein the memory elements each comprises:
a first transistor;
an n-channel transistor;
a p-channel transistor;
a capacitor;
an input terminal;
an output terminal; and
a terminal,
wherein one of a source and a drain of the first transistor is electrically connected to one of electrodes of the capacitor, a gate of the n-channel transistor, and a gate of the p-channel transistor,
wherein the other of the electrodes of the capacitor is electrically connected to the terminal,
wherein one of a source and a drain of the n-channel transistor is electrically connected to one of a source and a drain of the p-channel transistor,
wherein the input terminal is electrically connected to the other of the source and the drain of the p-channel transistor, and
wherein the output terminal is electrically connected to the one of the source and the drain of the n-channel transistor and the one of the source and the drain of the p-channel transistor.
15. The lookup table according to claim 14 , wherein a channel length of the n-channel transistor is twice or more a channel length of the p-channel transistor.
16. The lookup table according to claim 14 , further comprising a second memory element electrically connected to one of the first multiplexers in a level other than the lowermost level.
17. The lookup table according to claim 14 , further comprising an inverter electrically connected to an output terminal of one of the first multiplexers in a level other than the lowermost level.
18. A programmable logic device comprising the lookup table according to claim 14 .