Method and apparatus for electronic switching with low insertion loss and high isolation

• US 6,774,701 B1
• Filed: 02/19/2003
• Issued: 08/10/2004
• Est. Priority Date: 02/19/2003
• Status: Expired due to Fees

• Current Assignee: OL Security LLC (Intellectual Ventures LLC)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Heston, David D., Heston, John G.
• Primary Examiner(s): NGUYEN, LONG T
• Application Number:
  US10/369,782
• Time in Patent Office: 538 Days
• Field of Search: 327/407-413, 327/427, 327/436, 327/581, 327/376, 327/377, 327/308, 327/403, 327/404, 327/430, 327/431, 327/261, 327/281, 327/288, 303/101, 303/103, 455/83, 455/560, 455/277.1
• US Class Current: 327/408
• CPC Class Codes: H03K 17/162 without feedback from the output circuit to the control circuit
• CPC Class Codes: H03K 17/693 Switching arrangements with several input- or output-terminals, e.g. multiplexers, distributors logic circuits H03K19/00; code converters H03M5/00, H03M7/00

Abstract

A switch circuit includes a first electronic switch coupled between two terminals, and a second electronic switch and a capacitor coupled in series between a reference voltage and a control input of the first electronic switch. A different switch circuit includes first and second electronic switches coupled in series between two terminals with a further terminal coupled to a node between the switches, a third electronic switch and a first capacitor coupled in series between a reference voltage and a control input of the first electronic switch, and a fourth electronic switch and a second capacitor coupled in series between a reference voltage and a control input of the second electronic switch.

Claims

1. An apparatus, comprising:

first and second terminals;

a first electronic switch coupled between said first and second terminals, said first electronic switch having a first control input; and

a capacitor and a second electronic switch coupled in series between said first control input and a reference voltage, said second electronic switch having a second control input; and

a control circuit operable to effect switching of an RF signal applied to the first terminal to the second terminal and isolate the first electronic switch from the capacitor by applying a first control signal to the first control input and a second control signal to the second control input.

2. An apparatus according to claim 1, wherein said electronic switches each include a transistor.

3. An apparatus according to claim 2, wherein said transistor of said first electronic switch is a field effect transistor, said first control input being a gate input thereof.

4. An apparatus according to claim 3, wherein said transistor of said second electronic switch is a field effect transistor, said second control input being a gate input thereof.

5. An apparatus according to claim 2, wherein said transistor of said second electronic switch is a field effect transistor, said second control input being a gate input therof.

6. An apparatus according to claim 1, wherein said capacitor is disposed electrically between said first control input and said second electronic switch.

7. An apparatus according to claim 1, wherein said second electronic switch is disposed electrically between said first control input and said capacitor.

8. An apparatus, comprising:

first, second and third terminals;

first and second electronic switches coupled in series between said first and second terminals, said first and second terminals for receiving first and second RF signals, respectively, said first electronic switch having a first control input and said second electronic switch having a second control input, and said third terminal being coupled to a node between said first and second electronic switches;

a first capacitor and a third electronic switch coupled in series between said first control input and a first reference voltage, said third electronic switch having a third control input;

a second capacitor and a fourth electronic switch coupled in series between said second control input and a second reference voltage, said fourth electronic switch having a fourth control input; and

wherein said first capacitor is disposed electrically between said first control input and said third electronic switch, and said second capacitor is disposed electrically between said second control input and said fourth electronic switch.

9. An apparatus according to claim 8, wherein each of said electronic switches includes a transistor.

10. An apparatus according to claim 9, wherein said transistor of each of said first and second electronic switches is a field effect transistor, said first and second control inputs each being a gate input of a respective said transistor.

11. An apparatus according to claim 10,

wherein said field effect transistor of said first electronic switch has a drain coupled to said third terminal and a source coupled to said first terminal; and

wherein said field effect transistor of said second electronic switch has a drain coupled to said third terminal and a source coupled to said second terminal.

12. An apparatus according to claim 10, wherein said transistor of each of said third and fourth electronic switches is a field effect transistor, said third and fourth inputs each being a gate input of a respective said transistor.

13. An apparatus according to claim 9, wherein said transistor of each of said third and fourth electronic switches is a field effect transistor, said third and fourth control inputs each being a gate input of a respective said transistor.

14. An apparatus according to claim 8, wherein said first control input is coupled to said fourth control input, and said second control input is coupled to said third control input.

15. An apparatus according to claim 8, wherein said first, second and third terminals, said first, second, third and fourth electronic switches, and said first and second capacitors are included within a cellular telephone.

16. The apparatus of claim 8 wherein the first reference voltage and the second reference voltage are the same.

17. A method of switching a radio frequency signal between first and second terminals comprising:

coupling a first electronic switch between the first and second terminals, the first electronic switch having a first control input;

coupling a capacitor and a second electronic switch in series between the first control input and a reference voltage, the second electronic switch having a second control input;

providing the radio frequency signal at the first terminal;

transmitting the radio frequency signal to the second terminal by applying a first control signal to the first control input of the first electronic switch; and

isolating the capacitor from the first electronic switch while transmitting the radio frequency signal from the first terminal to the second terminal by applying a second control signal to the second control input.

18. A method according to claim 17, including configuring each of said first and second electronic switches to include a transistor.

19. A method according to claim 18, wherein said configuring of said first electronic switch includes configuring said first electronic switch to include a field effect transistor, said first control input being a gate of said field effect transistor.

20. A method according to claim 19, wherein said configuring of said second electronic switch includes configuring said second electronic switch to include a field effect transistor, said second control input being a gate of said field effect transistor of said second electronic switch.

21. A method according to claim 18, wherein said configuring of said second electronic switch includes configuring said second electronic switch to include a field effect transistor, said second control input being a gate of said field effect transistor.

22. A method according to claim 17, wherein said providing of said second electronic switch and said capacitor is carried out so that said second electronic switch is disposed electrically between first control input and said capacitor.

23. A method according to claim 17, wherein said providing of said second electronic switch and said capacitor is carried out so that said capacitor is disposed electrically between first control input and said second electronic switch.

24. A method of controlling a circuit having first and second electronic switches coupled in series between first and second terminals, and having third terminal coupled to a node between said first and second electronic switches, said first and second electronic switches respectively having first and second control inputs, said method comprising:

providing a third electronic switch and a first capacitor which are coupled in series between said first control input and a first reference voltage;

providing a fourth electronic switch and a second capacitor which are coupled in series between said second control input and a second reference voltage;

selectively applying control voltages to each of said first, second, third and fourth control inputs; and

wherein said selectively applying said control voltages includes selectively applying a first control voltage to each of said first and fourth control inputs, and a second control voltage to each of said second and third control inputs.

25. A method according to claim 24, wherein said providing of said third and fourth electronic switches includes configuring each of said third and fourth electronic switches to include a transistor.

26. A method according to claim 24, wherein said providing of said third and fourth electronic switches includes configuring each of said third and fourth electronic switches to include a field effect transistor, each of said third and fourth control inputs being a gate input of a respective said field effect transistor.

27. A method according to claim 24, wherein said providing of said third electronic switch and said first capacitor is carried out so that said first capacitor is disposed electrically between first control input and said third electronic switch;

and wherein said providing of said fourth second electronic switch and said second capacitor is carried out so that said second capacitor is disposed electrically between second control input and said fourth electronic switch.

28. A method according to claim 24, wherein said providing of said third electronic switch and said first capacitor is carried out so that said third electronic switch is disposed electrically between first control input and said first capacitor;

and wherein said providing of said fourth second electronic switch and said second capacitor is carried out so that said fourth electronic switch is disposed electrically between second control input and said second capacitor.

29. The method of claim 24, wherein the first reference voltage and the second reference voltage are the same.

30. An apparatus, comprising:

first, second and third terminals;

first and second electronic switches coupled in series between said first and second terminals, said first electronic switch having a first control input and said second electronic switch having a second control input, and said third terminal being coupled to a node between said first and second electronic switches;

a first capacitor and a third electronic switch coupled in series between said first control input and a first reference voltage, said third electronic switch having a third control input;

a second capacitor and a fourth electronic switch coupled in series between said second control input and a second reference voltage, said fourth electronic switch having a fourth control input; and

a control circuit operable to effect switching of a first RF signal applied to the first terminal to the third terminal, including isolating the first capacitor from the first electronic switch, by selectively applying a first control signal to the first control input and a third control signal to the third control input, and further operable to effect switching of a second RF signal applied to the second terminal to the third terminal, including isolating the second capacitor from the second electronic switch, by selectively applying a second control signal to the second control input and a fourth control signal to the fourth control input.

31. An apparatus according to claim 30, wherein each of said electronic switches includes a transistor.

32. An apparatus according to claim 31, wherein said transistor of each of said first and second electronic switches is a field effect transistor, said first and second control inputs each being a gate input of a respective said transistor.

33. An apparatus according to claim 32,

wherein said field effect transistor of said first electronic switch has a drain coupled to said third terminal and a source coupled to said first terminal; and

wherein said field effect transistor of said second electronic switch has a drain coupled to said third terminal and a source coupled to said second terminal.

34. An apparatus according to claim 32, wherein said transistor of each of said third and fourth electronic switches is a field effect transistor, said third and fourth control inputs each being a gate input of a respective said transistor.

35. An apparatus according to claim 34,

wherein said field effect transistor of said first electronic switch has a drain coupled to said third terminal and a source coupled to said first terminal;

wherein said field effect transistor of said second electronic switch has a drain coupled to said third terminal and a source coupled to said second terminal;

wherein said field effect transistor of said third electronic switch has a drain coupled to said first control input and a source coupled to one end of said first capacitor; and

wherein said field effect transistor of said fourth electronic switch has a drain coupled to said second control input and a source coupled to one end of said second capacitor.

36. An apparatus according to claim 31, wherein said transistor of each of said third and fourth electronic switches is a field effect transistor, said third and fourth control inputs each being a gate input of a respective said transistor.

37. An apparatus according to claim 36,

wherein said field effect transistor of said third electronic switch has a drain coupled to said first control input and a source coupled to one end of said first capacitor;

and

wherein said field effect transistor of said fourth electronic switch has a drain coupled to said second control input and a source coupled to one end of said second capacitor.

38. An apparatus according to claim 30, wherein said first control input is coupled to said fourth control input, and said second control input is coupled to said third control input.

39. An apparatus according to claim 30, wherein said first capacitor is disposed electrically between said first control input and said third electronic switch, and said second capacitor is disposed electrically between said second control input and said fourth electronic switch.

40. An apparatus according to claim 30, wherein said third electronic switch is disposed electrically between said first control input and said first capacitor, and said fourth electronic switch is disposed electrically between said second control input and said second capacitor.

41. An apparatus according to claim 30, wherein said first, second and third terminals, said first, second, third and fourth electronic switches, and said first and second capacitors are included within a cellular telephone.

42. A method of controlling a circuit having first and second electronic switches coupled in series between first and second terminals, said first and second terminals for receiving first and second RF signals, respectively, and having a third terminal coupled to a node between said first and second electronic switches, said first and second electronic switches respectively having first and second control inputs, said method comprising:

providing a third electronic switch and a first capacitor which are coupled in series between said first control input and a first reference voltage;

providing a fourth electronic switch and a second capacitor which are coupled in series between said second control input and a second reference voltage;

selectively applying control voltages to each of said first, second, third, and fourth control inputs; and

wherein said providing of said third electronic switch and said first capacitor is carried out so that said first capacitor is disposed electrically between first control input and said third electronic switch; and

wherein said providing of said fourth second electronic switch and said second capacitor is carried out so that said second capacitor is disposed electrically between second control input and said fourth electronic switch.

43. A method of controlling a circuit having first and second electronic switches coupled in series between first and second terminals, and having a third terminal coupled to a node between said first and second electronic switches, said first and second electronic switches respectively having first and second control inputs, said method comprising:

providing a third electronic switch and a first capacitor which are coupled in series between said first control input and a first reference voltage;

providing a fourth electronic switch and a second capacitor which are coupled in series between said second control input and a second reference voltage;

applying respective RF signals to the first and second terminals;

selectively switching the respective RF signals to the third terminal by;

selectively applying a first control signal to the fist control input of the first electronic switch and selectively isolating the second capacitor from the second electronic switch by applying a third control signal to the third control input of the third electronic switch; and

selectively applying a second control signal to the second control input of the second electronic switch and selectively isolating the second capacitor from the second electronic switch by applying a fourth control signal to the fourth control input of the fourth electronic switch.