Extended bandwidth amplifier and oscillator using positive current feedback through inductive load

• US 7,215,194 B2
• Filed: 05/28/2004
• Issued: 05/08/2007
• Est. Priority Date: 05/28/2004
• Status: Expired due to Fees

• Current Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Original Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Inventors: Kornegay, Kevin, Kucharski, Daniel
• Primary Examiner(s): NGUYEN, KHANH V
• Application Number:
  US10/857,582
• Publication Number:
  US 20050264356A1
• Time in Patent Office: 1,075 Days
• Field of Search: 330/252, 330/253, 326/115
• US Class Current: 330/252
• CPC Class Codes: H03F 1/42 Modifications of amplifiers to extend the bandwidth
• CPC Class Codes: H03F 2203/45638 the LC comprising one or more coils
• CPC Class Codes: H03F 2203/45702 the LC comprising two resistors
• CPC Class Codes: H03F 3/45085 Long tailed pairs H03F3/45112, H03F3/45139 take precedence
• CPC Class Codes: H03F 3/45475 using IC blocks as the active amplifying circuit

Abstract

Circuit topologies that provide extended bandwidth of operation are disclosed. The circuits have two stages that share inductors, in which in-phase current components sum at a summing node and flow together, increasing the magnitude of the current in the inductors. The inductive peaking exhibited by the circuits is increased without using excessively large inductors.

Claims

1. An extended bandwidth active circuit device, comprising:

at least two inductors, each inductor having an inductance, a first terminal, and a second terminal, each first terminal thereof in common electrical communication;

a plurality of active circuit elements, each of said active circuit elements having a first terminal and a second terminal, at least a first pair of active circuit elements and a second pair of active circuit elements configured to conduct mutually in-phase current components; and

two summing nodes, each summing node having an electrical connection to a first terminal of one member of said first pair of active circuit elements and a first terminal of one member of said second pair of active circuit elements, said electrical connection configured so that said in-phase current components sum at said summing nodes, each of said summing nodes in electrical communication with a respective one of said second terminals of said inductors;

whereby, when said in-phase current components sum and flow through said two inductors, said extended bandwidth active circuit device provides inductive peaking.

2. The extended bandwidth active circuit device according to claim 1, wherein said inductive peaking is proportional to a first derivative of said summed in-phase current component.

3. The extended bandwidth active circuit device according to claim 1, wherein said inductive peaking is proportional to a sum of said inductances of said inductors.

4. The extended bandwidth active circuit device according to claim 1, further comprising:

a first reference voltage terminal and a second reference voltage terminal; and

wherein said first terminal of said inductors in common electrical communication are in electrical communication with a selected one of said first and said second reference voltage terminals; and

wherein said respective second terminals of one member of said first pair and one member of said second pair of active circuit elements are in electrical communication with the other of said first and said second reference voltage terminals.

5. The extended bandwidth active circuit device according to claim 1, wherein said extended bandwidth active circuit device comprises an amplifier.

6. The extended bandwidth active circuit device according to claim 1, wherein said extended bandwidth active circuit device comprises an oscillator.

7. The extended bandwidth active circuit device according to claim 1, wherein said extended bandwidth active circuit device comprises at least one of an emitter follower, a source follower, a common emitter, a common source, a common base, a common gate, and a differential pair.

8. The extended bandwidth active circuit device according to claim 7, further comprising supplemental circuitry.

9. The extended bandwidth active circuit device according to claim 8, wherein said supplemental circuitry comprises a local feedback.

10. The extended bandwidth active circuit device according to claim 1, wherein said extended bandwidth active circuit device comprises a single ended input.

11. The extended bandwidth active circuit device according to claim 1, wherein said extended bandwidth active circuit device comprises a differential input.

12. The extended bandwidth active circuit device according to claim 1, wherein said extended bandwidth active circuit device comprises a transistor.

13. The extended bandwidth active circuit device according to claim 12, wherein said transistor is a selected one of a junction transistor and a field effect transistor.

14. The extended bandwidth active circuit device according to claim 1, wherein said extended bandwidth active circuit device comprises a transconductance device.

15. The extended bandwidth active circuit device according to claim 1, wherein at least one of said inductors is a circuit component exhibiting inductive characteristics and comprising one or more of a capacitor, a resistor and an active device.

16. An extended bandwidth active circuit device, comprising:

at least two inductors, each inductor having an inductance, a first terminal, and a second terminal, each first terminal thereof in common electrical communication;

a plurality of active circuit elements, each of said active circuit elements having a first terminal and a second terminal, at least first, second and third active circuit elements, of which said first and said second active circuit elements are configured to conduct mutually in-phase current components and said third active circuit element is configured to conduct a common return current substantially equal to a sum of said in-phase current components, said third active circuit element having a terminal in electrical communication with a selected one of said second terminals of said inductors;

at least one summing node having an electrical connection to a first terminal of said first active circuit element and a first terminal of said second active circuit element, said electrical connection configured so that said in-phase current components sum at said summing node, said at least one summing node in electrical communication with another one of said second terminals of said inductors;

whereby, when said in-phase current components sum and flow through said two inductors, said extended bandwidth active circuit device provides inductive peaking.

17. The extended bandwidth active circuit device according to claim 16, wherein said inductive peaking is proportional to a first derivative of said summed in-phase current component.

18. The extended bandwidth active circuit device according to claim 16, wherein said inductive peaking is proportional to a sum of said inductances of said inductors.

19. A method of providing inductive peaking in an extended bandwidth active circuit device, comprising the steps of:

generating in a circuit having at least two active circuit elements at least two currents having mutually in-phase current components;

summing said at least two in-phase current components at a summing node to generate a summed current component; and

applying said summed current component to at least one inductor, said at least one inductor having an inductance;

whereby, when said in-phase current components sum and flow through said at least one inductor, inductive peaking is provided in said extended bandwidth active circuit device.

20. The method according to claim 19, wherein said inductive peaking is proportional to a first derivative of said summed in-phase current component.

21. The method according to claim 19, wherein said inductive peaking is proportional to an equivalent inductance of said at least one inductor.