System for controlling power to sequential and combinatorial logic circuitry in an integrated circuit
View Patent ↗A method for reducing power consumption in an integrated circuit and an integrated circuit having a power reduction feature. The integrated circuit has at least two functional circuit blocks and two upper supply rails. A first upper supply rail is coupled to the first functional circuit block and a second upper supply rail is coupled to the second functional circuit block. A lower supply rail is coupled to the first and second functional circuit blocks. In an active mode of operation, a first source of operating potential is electrically coupled to the first upper supply rail and a second source of operating potential is electrically coupled to the second upper supply rail. In an idle mode of operation, the first upper supply rail remains electrically coupled to the first source of operating potential and the second source of operating potential is electrically decoupled from the second functional circuit block.
1. An integrated circuit, comprising:
first and second functional circuit blocks; and
first, second, and third power supply rails, wherein the first and second power supply rails are upper supply rails and the third power supply rail is a lower power supply rail, wherein the first functional circuit block is electrically coupled to the first power supply rail, the second functional circuit block is electrically coupled to the second power supply rail, and the third power supply rail is electrically coupled to at least one of the first and second functional circuit blocks, wherein the second power supply rail is switchably coupled to a source of operating potential, wherein the first functional block comprises sequential logic circuitry and the second functional circuit block comprises combinational logic circuitry, and wherein a first source of operating potential is coupled to the first functional block and a second source of operating potential is coupled to the first and second functional blocks in an active operational state.
2. The integrated circuit of claim 1 , further including a switching element coupled between the first and second power supply rails.
3. The integrated circuit of claim 2 , wherein the switching element is a switching transistor.
4. The integrated circuit of claim 1 , wherein the second source of operating potential is decoupled from the second functional block in a suspended operational state.
5. The integrated circuit of claim 4 , wherein the first source of operating potential is coupled to the first functional block in the suspended operational state.
6. The integrated circuit of claim 2 , wherein the switching element couples the second source of operating potential to the first functional block.
7. The integrated circuit of claim 2 , wherein the switching element decouples the second source of operating potential from the first functional block in a suspended operational state.
8. The integrated circuit of claim 1 , wherein the second power supply rail is switchably coupled to the second source of operating potential.
9. The integrated circuit of claim 1 , wherein the first and second sources of operating potential have substantially the same voltage.
10. The integrated circuit of claim 1 , further including a capacitor coupled between the first and third power supply rails.
11. The integrated circuit of claim 10 , wherein the capacitor comprises a transistor.
12. An integrated circuit, comprising:
first and second functional circuit blocks, wherein the first function circuit block comprises sequential logic circuitry and the second functional circuit block comprises combinatorial logic circuitry;
first, second, and third power supply rails, wherein the first functional circuit block is electrically coupled to the first power supply rail, the second functional circuit block is electrically coupled to the second power supply rail, and the third power supply rail is electrically coupled to at least one of the first and second functional circuit blocks, and wherein a first source of operating potential is coupled to the first functional block and a second source of operating potential is coupled to the first and second functional blocks in an active operational state; and
a switching element coupled between the first and second power supply rails.