Methods and systems for reducing leakage current in semiconductor circuits
View Patent ↗Leakage currents across circuit components such as transistors are avoided by placing circuits into a low-leakage standby mode. The circuits are configured such that voltage differentials across leakage-prone circuit components are avoided when in standby mode. Various means are used to configure the circuits, such as configuration ports, data input lines, scan chains, etc. In embodiments containing reconfigurable devices, low-threshold transistors are used to implement the routing network.
1. A circuit, comprising: a data input, a data output, a first voltage supply input, a second voltage supply input, a high threshold device electrically coupled between the data input and the data output, and electrically coupled between the first and second voltage supply inputs, and a low threshold device electrically coupled between the data input and the data output, and electrically coupled between the first and second voltage supply inputs; wherein the circuit is adapted to be switched to a low leakage state by providing a signal on the data input that causes the circuit to enter the low leakage state.
2. The circuit of claim 1 , wherein the low leakage state comprises a leakage current path from the first voltage supply input to the second voltage supply input, the leakage current path flowing through the high threshold device, the high threshold device being turned off.
3. The circuit of claim 1 , wherein the low leakage state comprises a standby mode for the circuit.
4. The circuit of claim 1 , wherein the first voltage supply input comprises a CMOS high voltage supply input.
5. The circuit of claim 1 , wherein the second voltage supply input comprises a CMOS low voltage supply input.
6. The circuit of claim 1 , wherein the high threshold device comprises a MOS device.
7. The circuit of claim 6 , wherein the MOS device comprises a transistor.
8. The circuit of claim 1 , wherein the low threshold device comprises a MOS device.
9. The circuit of claim 8 , wherein the MOS device comprises a transistor.
10. The circuit of claim 1 , further comprising a second data input, a second high threshold device electrically coupled between the second data input and the data output, and electrically coupled between the first and second voltage supply inputs, and a second low threshold device electrically coupled between the second data input and the data output, and electrically coupled between the first and second voltage supply inputs, wherein the circuit is adapted to be switched to a low leakage state by providing a second signal on the second data input which in combination with the signal on the first data input causes the circuit to enter the low leakage state.
11. The circuit of claim 1 , wherein the circuit comprises a controlled buffer.
12. The circuit of claim 1 , wherein the circuit comprises a driver circuit.
13. The circuit of claim 1 , further comprising a first register electrically coupled to the data input, the register comprising a test input, wherein the first register is adapted to provide the signal on the data input, and wherein the first register is adapted to receive a signal on the test input, and propagate that signal to the data input.
14. The circuit of claim 13 , wherein the first register is one of a plurality of registers coupled together by a scan chain, the scan chain adapted to receive a series of data values and to load the series of data values into the plurality of registers.
15. The circuit of claim 14 , wherein the circuit is adapted to be placed into a low leakage state by supplying a pre-determined series of data values to the scan chain, loading the predetermined series of data values into the plurality of registers, causing the first register to propagate one of the pre-determined data values to the data input, and causing the circuit to enter the low leakage state.
16. The circuit of claim 1 , wherein the circuit comprises an integrated circuit.
17. A circuit, comprising: a data input, a data output, a low threshold device electrically coupled between the data input and the data output, a control input adapted to receive a control signal for controlling the low threshold device, and a register electrically coupled between the data input and the low threshold device, the register adapted to provide a register value to the low threshold device; wherein the circuit is adapted to be placed into a low leakage state by causing the register value to be a low leakage value, which causes the circuit to enter the low leakage state, and wherein the low threshold device is electrically coupled to the control input.
18. The circuit of claim 17 , wherein the data output comprises a data output value of a first voltage level, and the low leakage value comprises a second voltage level substantially equivalent to the first voltage level.
19. The circuit of claim 17 , wherein the register value is caused to be a low leakage value by providing the low leakage value as an input on the data input.
20. The circuit of claim 17 , wherein the register further comprises a configuration input, and the register value is caused to be a low leakage value by providing the low leakage value as an input on the configuration input.
21. The circuit of claim 17 , wherein the register further comprises a reset input, and the register value is caused to be a low leakage value by providing a reset signal to the reset input.
22. The circuit of claim 17 , wherein the register further comprises a test input, and the register value is caused to be a low leakage value by providing the low leakage value as an input on the test input.
23. The circuit of claim 22 , wherein the register is one of a plurality of registers, the plurality of registers coupled together by a scan chain, the scan chain adapted to receive a series of data values and to load the series of data values into the plurality of registers.
24. The circuit of claim 23 , wherein the circuit is adapted to be placed into a low leakage state by supplying a pre-determined series of data values to the scan chain, loading the predetermined series of data values into the plurality of registers, causing the first register to propagate one of the pre-determined data values as the register value to the low threshold device, and causing the circuit to enter the low leakage state.
25. The circuit of claim 17 , wherein the low threshold device comprises a pass transistor.