Multi-operational amplifier system
View Patent ↗A multi-operational amplifier system comprises a plurality of operational amplifiers and a controller to configure the plurality of operational amplifiers. The operational amplifiers may be selectively configured to operate individually or in combination with other of the operational amplifiers. The operational amplifiers may have different common node inputs. In one aspect, the different inputs may be selected from groups of PMOS, N-type NMOS and NZ NMOS inputs. The operational amplifiers may include the different inputs that are arranged as differential pairs.
1. A multi-operational amplifier system comprising:
a plurality of operational amplifiers each having inputs and predetermined transfer characteristics; and
a controller configured to interconnect the inputs of the plurality of operational amplifiers by connecting the inputs of pairs of the operational amplifiers and by disconnecting ones of the operational amplifiers, the controller being reconfigurable to select different combinations of the operational amplifiers so as to provide an overall desired transfer characteristic.
2. The multi-operational amplifier system of claim 1 wherein at least one of the plurality of operational amplifiers includes an N-type NMOS input, at least one of the plurality of operational amplifiers includes a PMOS input, and the controller is configurable to select between the transfer characteristics of the N-type NMOS and the PMOS inputs.
3. The multi-operational amplifier system of claim 1 wherein at least one of the plurality of operational amplifiers includes an N-type NMOS input, at least one of the plurality of operational amplifiers includes a PMOS input, at least one of the plurality of operational amplifiers includes an NZ NMOS input, and the controller is configured to select between the transfer characteristics of N-type NMOS, PMOS and NZ NMOS inputs.
4. The multi-operational amplifier system of claim 1 wherein at least two operational amplifiers are configured as an output transconductance amplifier and at least one operational amplifier is configured as a folded cascade operational amplifier.
5. The multi-operational amplifier system of claim 4 wherein one of said two operational amplifiers configured as an output transconductance amplifier includes a PMOS input differential pair.
6. The multi-operational amplifier system of claim 4 wherein another one of said at least two operational amplifiers configured as an output transconductance amplifier includes an NZ NMOS input differential pair.
7. The multi-operational amplifier system of claim 4 wherein said operational amplifiers configured as a folded cascade operational amplifier includes an N-type NMOS input differential pair.
8. The multi-operational amplifier system of claim 4 wherein said at least two operational amplifiers configured as an output transconductance amplifier and said operational amplifiers configured as a folded cascade operational amplifier each comprise an output stage that includes a source follower.
9. The multi-operational amplifier system of claim 1 wherein each operational amplifier includes a compensation network, and an output of one of said plurality of operational amplifiers is coupled to an input of a compensation network of at least one other of said plurality of operational amplifiers.
10. A multi-operational amplifier system comprising:
a plurality of operational amplifiers each having inputs; and
a controller configured to interconnect the inputs of the plurality of operational amplifiers by connecting the inputs of pairs of at least two of the plurality of operational amplifiers and by disconnecting at least one of the plurality of operational amplifiers;
wherein the controller is reconfigurable to select different combinations of operational amplifiers so as to provide a buffer, an extended wide common mode input and form an adaptive input range of said multi-operational amplifier system.
11. The multi-operational amplifier system of claim 10 wherein the controller is configured to select a first operational amplifier to act as a unity buffer.
12. The multi-operational amplifier system of claim 11 wherein the controller is configured to select a second operational amplifier to act as a buffer.
13. The multi-operational amplifier system of claim 10 wherein the controller is configured to couple at least two of the plurality of operational amplifiers together to act as a unity buffer.
14. The multi-operational amplifier system of claim 10 wherein at least two operational amplifiers are configured as an output transconductance amplifier and at least one operational amplifier is configured as a folded cascade operational amplifier.
15. The multi-operational amplifier system of claim 14 wherein one of said two operational amplifiers configured as an output transconductance amplifier includes a PMOS input differential pair.
16. The multi-operational amplifier system of claim 14 wherein another one of said at least two operational amplifiers configured as an output transconductance amplifier includes an NZ NMOS input differential pair.
17. The multi-operational amplifier system of claim 14 wherein said operational amplifiers configured as a folded cascade operational amplifier includes an N-type NMOS input differential pair.
18. The multi-operational amplifier system of claim 14 wherein said at least two operational amplifiers configured as an output transconductance amplifier and said operational amplifiers configured as a folded cascade operational amplifier each comprise an output stage that includes a source follower.
19. The multi-operational amplifier system of claim 10 wherein each operational amplifier includes a compensation network, and an output of one of said plurality of operational amplifiers is coupled to an input of a compensation network of at least one other of said plurality of operational amplifiers.
20. A multi-operational amplifier system comprising:
a plurality of operational amplifiers each having inputs, wherein each amplifier operates as a buffer or unity buffer; and
a controller configured to interconnect the inputs of the plurality of operational amplifiers by connecting the inputs of pairs of at least two of the plurality of operational amplifiers and by disconnecting at least one of the plurality of operational amplifiers;
wherein the controller is reconfigurable to select different combinations of operational amplifiers so as to provide an extended wide common mode input and form an adaptive input range of said multi-operational amplifier system.
21. The multi-operational amplifier system of claim 20 wherein at least two operational amplifiers are configured as an output transconductance amplifier and at least one operational amplifier is configured as a folded cascade operational amplifier.
22. The multi-operational amplifier system of claim 21 wherein one of said two operational amplifiers configured as an output transconductance amplifier includes a PMOS input differential pair.
23. The multi-operational amplifier system of claim 21 wherein another one of said at least two operational amplifiers configured as an output transconductance amplifier includes an NZ NMOS input differential pair.
24. The multi-operational amplifier system of claim 21 wherein said operational amplifiers configured as a folded cascade operational amplifier includes an N-type NMOS input differential pair.
25. The multi-operational amplifier system of claim 21 wherein said at least two operational amplifiers configured as an output transconductance amplifier and said operational amplifiers configured as a folded cascade operational amplifier each comprise an output stage that includes a source follower.
26. The multi-operational amplifier system of claim 20 wherein each operational amplifier includes a compensation network, and an output of one of said plurality of operational amplifiers is coupled to an input of a compensation network of at least one other of said plurality of operational amplifiers.
27. A multi-operational amplifier system comprising:
a plurality of operational amplifiers each having inputs and a bias;
a common mode range detection circuit configured to actively maintain the bias of a first operational amplifier of the plurality of operational amplifiers as a constant; and
a controller configured to interconnect the inputs of the plurality of operational amplifiers by connecting the inputs of pairs of at least two of the plurality of operational amplifiers and by disconnecting at least one of the plurality of operational amplifiers;
wherein the controller is reconfigurable to select different combinations of operational amplifiers so as to provide an extended wide common mode input and form an adaptive input range of said multi-operational amplifier system.
28. The multi-operational amplifier system of claim 27 wherein the common mode range detection circuit comprises a plurality of PMOS transistors and an NMOS transistor within the first operational amplifier of the plurality of operational amplifiers.
29. The multi-operational amplifier system of claim 27 wherein at least two operational amplifiers are configured as an output transconductance amplifier and at least one operational amplifier is configured as a folded cascade operational amplifier.
30. The multi-operational amplifier system of claim 29 wherein one of said two operational amplifiers configured as an output transconductance amplifier includes a PMOS input differential pair.
31. The multi-operational amplifier system of claim 29 wherein another one of said at least two operational amplifiers configured as an output transconductance amplifier includes an NZ NMOS input differential pair.
32. The multi-operational amplifier system of claim 29 wherein said operational amplifiers configured as a folded cascade operational amplifier includes an N-type NMOS input differential pair.
33. The multi-operational amplifier system of claim 29 wherein said at least two operational amplifiers configured as an output transconductance amplifier and said operational amplifiers configured as a folded cascade operational amplifier each comprise an output stage that includes a source follower.
34. The multi-operational amplifier system of claim 27 wherein each operational amplifier includes a compensation network, and an output of one of said plurality of operational amplifiers is coupled to an input of a compensation network of at least one other of said plurality of operational amplifiers.
35. The multi-operational amplifier system of claim 27 wherein one of said plurality of operational amplifiers selectively switches a compensation network based on a compensation usage of another one of said plurality of operational amplifiers.
36. A multi-operational amplifier system comprising:
a plurality of operational amplifiers each having inputs and a bias, wherein the bias of at least one of the plurality of operational amplifiers is an actively switchable bias; and
a controller configured to interconnect the inputs of the plurality of operational amplifiers by connecting the inputs of pairs of at least two of the operational amplifiers and by disconnecting at least one of the plurality of operational amplifiers;
wherein the controller is reconfigurable to select different combinations of operational amplifiers so as to provide an extended wide common mode input and form an adaptive input range of said multi-operational amplifier system and the controller is configured to actively maintain the actively switchable bias as a constant.
37. The multi-operational amplifier system of claim 36 wherein at least two operational amplifiers are configured as an output transconductance amplifier and at least one operational amplifier is configured as a folded cascade operational amplifier.
38. The multi-operational amplifier system of claim 37 wherein one of said two operational amplifiers configured as an output transconductance amplifier includes a PMOS input differential pair.
39. The multi-operational amplifier system of claim 37 wherein another one of said at least two operational amplifiers configured as an output transconductance amplifier includes an NZ NMOS input differential pair.
40. The multi-operational amplifier system of claim 37 wherein said operational amplifiers configured as a folded cascade operational amplifier includes an N-type NMOS input differential pair.
41. The multi-operational amplifier system of claim 37 wherein said at least two operational amplifiers configured as an output transconductance amplifier and said operational amplifiers configured as a folded cascade operational amplifier each comprise an output stage that includes a source follower.
42. The multi-operational amplifier system of claim 36 wherein each operational amplifier includes a compensation network, and an output of one of said plurality of operational amplifiers is coupled to an input of a compensation network of at least one other of said plurality of operational amplifiers.
43. The multi-operational amplifier system of claim 36 wherein one of said plurality of operational amplifiers selectively switches a compensation network based on a compensation usage of another one of said plurality of operational amplifiers.