SWITCHED CAPACITOR VOLTAGE CONVERTERS

• US 20100214014A1
• Filed: 02/25/2009
• Published: 08/26/2010
• Est. Priority Date: 02/25/2009
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Montoye, Robert K., Dennard, Robert H., Ji, Brian L.
• Granted Patent: US 8,248,152 B2
• Time in Patent Office: Days
• US Class Current: 327/541
• CPC Class Codes: G11C 5/145 Applications of charge pumps; Boosted voltage circuits; Clamp circuits therefor G11C5/141 takes precedence
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps

Abstract

An on-chip voltage conversion apparatus for integrated circuits includes a first capacitor; a first NFET device configured to selectively couple a first electrode of the first capacitor to a low side voltage rail of a first voltage domain; a first PFET device configured to selectively couple the first electrode of the first capacitor to a high side voltage rail of the first voltage domain; a second NFET device configured to selectively couple a second electrode of the first capacitor to a low side voltage rail of a second voltage domain, wherein the low side voltage rail of the second voltage domain corresponds to the high side voltage rail of the first voltage domain; and a second PFET device configured to selectively couple the second electrode of the first capacitor to a high side voltage rail of the second voltage domain.

Claims

1. An on-chip voltage conversion apparatus for integrated circuits, comprising:

a first capacitor;

a first NFET device configured to selectively couple a first electrode of the first capacitor to a low side voltage rail of a first voltage domain;

a first PFET device configured to selectively couple the first electrode of the first capacitor to a high side voltage rail of the first voltage domain;

a second NFET device configured to selectively couple a second electrode of the first capacitor to a low side voltage rail of a second voltage domain, wherein the low side voltage rail of the second voltage domain corresponds to the high side voltage rail of the first voltage domain; and

a second PFET device configured to selectively couple the second electrode of the first capacitor to a high side voltage rail of the second voltage domain.

2. The apparatus of claim 1, wherein the first capacitor comprises a deep trench capacitor.

3. The apparatus of claim 1, wherein the first and second NFET and PFET devices are formed on a silicon-on-insulator (SOI) substrate.

4. The apparatus of claim 1, wherein actuating signals to the first and second NFET and PFET devices are applied so as to charge and discharge the first capacitor between a first magnitude corresponding to the voltage difference across the first voltage domain and a second magnitude corresponding to the voltage difference across the second voltage domain.

5. The apparatus of claim 1, wherein for a down-conversion mode operation, the high side voltage rail of the second voltage domain, V2, is an input voltage and the high side voltage rail of the first voltage domain, V1, is an output voltage, such that V2>

2*V1.

6. The apparatus of claim 1, wherein for an up-conversion mode operation, the high side voltage rail of the first voltage domain, V1, is an input voltage and the high side voltage rail of the second voltage domain, V2, is an output voltage, such that V2<

2*V1.

7. The apparatus of claim 4, wherein the actuating signals to the first and second NFET and PFET devices are applied in a manner so as to prevent simultaneous conduction of any NFET device and any PFET device.

8. The apparatus of claim 4, wherein an output current is proportional to a switching frequency of the actuating signals.

9. The apparatus of claim 1, wherein:

gate terminals of the first NFET and PFET devices operate entirely within the first voltage domain; and

gate terminals of the second NFET and PFET devices operate entirely within the second voltage domain.

10. The apparatus of claim 1, further comprising:

one or more additional capacitors in series with the first capacitor;

one or more pairs of additional NFET and PFET devices associated with one or more additional voltage domains for each one or more additional capacitors so as to define a voltage converter that nominally converts a voltage level of N voltage units to a voltage level of M voltage units and vice versa;

wherein N represents the total number of pairs of NFET and PFET devices, N−

1 represents the total number of capacitors, and 1≦

M≦

N−

1.

11. The apparatus of claim 10, wherein the pairs of NFET and PFET devices in each voltage domain are controlled in a manner so as to charge and discharge the associated capacitor between a first magnitude and a second magnitude, wherein for the X^th capacitor of the apparatus, the first magnitude corresponds to the voltage difference across the X^th voltage domain and the second magnitude corresponds to the voltage difference across the (X+1)^th voltage domain.

12. The apparatus of claim 11, wherein the NFET and PFET devices are operated in a manner so as to prevent simultaneous conduction of any NFET device and any PFET device.

13. The apparatus of claim 10, wherein for a down-converter mode of operation, the converter serves an N-to-M down-converter.

14. The apparatus of claim 10, wherein for an up-converter mode of operation, the converter serves an M-to-N up-converter.

15. The apparatus of claim 10, wherein a first plurality of voltage levels are converted to a second plurality of voltage levels.

16. The apparatus of claim 1, wherein the first and second NFET and PFET devices are formed on bulk silicon substrates with triple well technology.

17. An on-chip voltage conversion system for integrated circuits, comprising:

a clock source having a plurality of clock phases;

a plurality of actuating signals corresponding to one of a plurality of phases; and

a plurality of voltage converters controlled by the actuating signals, with each voltage converter comprising;

a first capacitor;

a first NFET device configured to selectively couple a first electrode of the first capacitor to a low side voltage rail of a first voltage domain;

a first PFET device configured to selectively couple the first electrode of the first capacitor to a high side voltage rail of the first voltage domain;

a second NFET device configured to selectively couple a second electrode of the first capacitor to a low side voltage rail of a second voltage domain, wherein the low side voltage rail of the second voltage domain corresponds to the high side voltage rail of the first voltage domain; and

a second PFET device configured to selectively couple the second electrode of the first capacitor to a high side voltage rail of the second voltage domain.

18. An on-chip voltage conversion system for integrated circuits, comprising:

a clock source having a plurality of clock phases;

a plurality of actuating signals corresponding to one of a plurality of phases; and

a plurality of voltage converters controlled by the actuating signals, with each voltage converter comprising;

a first capacitor;

a first pair of NFET and PFET devices associated with a first voltage domain, with a first NFET of the first pair configured to selectively couple a first electrode of the first capacitor to a low side voltage rail of the first voltage domain, and a first PFET of the first pair configured to selectively couple the first electrode of the first capacitor to a high side voltage rail of the first voltage domain;

a second pair of NFET and PFET devices associated with a second voltage domain, with a second NFET of the second pair configured to selectively couple a second electrode of the first capacitor to a low side voltage rail of the second voltage domain, wherein the low side voltage rail of the second voltage domain corresponds to the high side voltage rail of the first voltage domain, and a second PFET of the second voltage domain configured to selectively couple the second electrode of the first capacitor to a high side voltage rail of the second voltage domain; and

one or more additional capacitors in series with the first capacitor;

one or more additional pairs of NFET and PFET devices associated with one or more additional voltage domains for each one or more additional capacitors so as to define a multiple level converter that nominally converts a voltage level of N voltage units to a voltage level of M voltage units and vice versa;

wherein N represents the total number of pairs of switching devices, N−

1 represents the total number of capacitors, and 1≦

M≦

N−

1.

19. The system of claim 18, wherein actuating signals to the pairs of NFET and PFET devices in each voltage domain are applied so as to charge and discharge the associated capacitor between a first magnitude and a second magnitude, wherein for the X^th capacitor of the apparatus, the first magnitude corresponds to the voltage difference across the X^th voltage domain and the second magnitude corresponds to the voltage difference across the (X+1)^th voltage domain.

20. The system of claim 19, wherein the actuating signals to the NFET and PFET devices in each pair are applied in a manner so as to prevent simultaneous conduction of the NFET and PFET devices.

21. A method of implementing on-chip voltage conversion for integrated circuits, the method comprising:

using a first NFET device to selectively couple a first electrode of a first capacitor to a low side voltage rail of a first voltage domain;

using a first PFET device to selectively couple the first electrode of the first capacitor to a high side voltage rail of the first voltage domain;

using a second NFET device to selectively couple a second electrode of the first capacitor to a low side voltage rail of a second voltage domain, wherein the low side voltage rail of the second voltage domain corresponds to the high side voltage rail of the first voltage domain; and

using a second PFET device to selectively couple the second electrode of the first capacitor to a high side voltage rail of the second voltage domain.

22. The method of claim 21, wherein the first capacitor comprises a deep trench capacitor.

23. The method of claim 22, wherein the first and second NFET and PFET devices are formed on a silicon-on-insulator (SOI) substrate.

24. The method of claim 21, further comprising applying actuating signals to the first and second NFET and PFET devices so as to charge and discharge the first capacitor between a first magnitude corresponding to the voltage difference across the first voltage domain and a second magnitude corresponding to the voltage difference across the second voltage domain.

25. The method of claim 24, wherein for a down-conversion mode operation, the voltage of the second voltage domain, V2, is an input voltage and the voltage of the first voltage domain, V1, is an output voltage, such that V2>

2*V1.

26. The method of claim 24, wherein for an up-conversion mode operation, the voltage of the first voltage domain, V1, is an input voltage and the voltage of the second voltage domain, V2, is an output voltage, such that V2<

2*V1.