Electronic switch controlled by plural inputs

• US 5,350,957 A
• Filed: 07/14/1993
• Issued: 09/27/1994
• Est. Priority Date: 10/20/1989
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Truitt, George A., Cooper, Steven W.
• Primary Examiner(s): Callahan, Timothy P.
• Assistant Examiner(s): PHAN, TRONG Q
• Application Number:
  US08/091,420
• Time in Patent Office: 440 Days
• Field of Search: 307/571, 307/585, 307/451, 307/443, 307/254, 307/241, 307/270, 307/296.8, 307/304, 323/224, 323/225, 323/226, 377/60
• US Class Current: 327/427
• CPC Class Codes: H03K 17/6871 the output circuit comprising more than one controlled field-effect transistor
• 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 switching circuit (34) is provided having first and second transistors (36, 38). A first control voltage V_C1, is applied to the gate (42) of the first transistor (36). A second control voltage, V_C2, is applied to the gate (50) of the second transistor (38). The transistors (36, 38) switch to generate the output signal, V_out, in response to the difference between the first and second control voltages.

Claims

1. A switching circuit, comprising:

(a) an input terminal and an output terminal;

(b) a first switch having a current path coupled to said input terminal and said output terminal and having an input for receiving a first control voltage;

(c) a second switch having a current path coupled to said current path of said first switch and to said output terminal and having an input for receiving a second control voltage, only one of said first switch and said second switch operable to conduct in response to a voltage difference between said first and second control voltages;

(d) a first capacitor coupled between said input terminal and said current path of said first switch; and

(e) a second capacitor coupled between said output terminal and said current path of said first switch;

(f) wherein said first switch comprises a first and second transistor each having a gate, said first and second transistor gates coupled together as said input for said first switch, and said second switch comprises a third and fourth transistor each having a gate, said third and fourth transistor gates coupled together as said input for said second switch.

2. The switching circuit of claim 1 wherein said first and second transistors further each include a first and second source/drain;

said first source/drain of said first transistor receiving an input signal;

said first source/drain of said second transistor transmitting an output signal; and

said second source/drain of said first transistor coupled to said second source/drain of said second transistor.

3. The switching circuit of claim 2 wherein said third and fourth transistors further each comprise a first and second source/drain;

said first source/drain of said third transistor coupled to said first source/drain of said fourth transistor;

said second source/drain of said third transistor coupled to said second source/drain of said first transistor; and

said second source/drain of said fourth transistor coupled to said first source/drain of said second transistor.

4. The switching circuit of claim 3 and further including a capacitor coupled between said first source/drain of both of said third and fourth transistors and ground.

5. A switching circuit, comprising:

(a) an input terminal and an output terminal;

(b) a first switch having a current path coupled to said first output terminal and having an input for receiving a first control voltage;

(c) a second switch having a current path coupled to said current path of said first switch, said output terminal and a source of reference voltage and having an input for receiving a second control voltage, only one said first switch of said second switch operable to conduct in response to a voltage difference between said first and second control voltages;

(d) a first capacitor coupled between said output terminal and said current path of said first switch;

(e) a third switch coupled between the current path of said first switch and said reference voltage source having an input for receiving said second control voltage;

(f) a fourth switch coupled between the current paths of said first and third switches and said input terminal having an input for receiving said first control voltage, only one of said third switch and said fourth switch being operable to conduct in response to said difference between said first and second control voltages.

6. A switching circuit, comprising:

(a) an input terminal and an output terminal;

(b) a first transistor coupled to said input terminal and having a gate for receiving a first control voltage and having a first and second source/drain;

(c) a second transistor associated with said first transistor, coupled to said output terminal and having a gate for receiving a second control voltage and having a first and second source/drain;

(d) only one of said first transistor or said second transistor conducting responsive to the difference between said first and second control voltages;

(e) a first capacitor coupled between said input terminal and said first transistor;

(f) a second capacitor coupled between said output terminal and said second transistor;

(g) a third transistor having a gate for receiving said first control voltage and having a first and second source/drain; and

(h) a fourth transistor having a gate for receiving said second control voltage and having a first and second source/drain;

(i) only one of said third transistor and said fourth transistor conducting responsive to the difference between said first and second control voltages.

7. A switching circuit, comprising:

a first switch having an input for receiving a first control voltage;

a second switch associated with said first switch and having an input for receiving a second control voltage, only one of said first and said second switch operable to conduct in response to the difference between said first and second control voltages;

said first switch comprising first and second transistors each having a gate, said first and second transistor gates coupled together as said input for said first switch, and said second switch comprising third and fourth transistors each having a gate, said third and fourth transistor gates coupled together as said input for said second switch.

8. The switching circuit of claim 7 wherein said first and second transistors further each include a first and second source/drain;

said first source/drain of said first transistor receiving an input signal;

said first source/drain of said second transistor transmitting an output signal; and

said second source/drain of said first transistor coupled to said second source/drain of said second transistor.

9. The switching circuit of claim 8 wherein said third and fourth transistors further each comprise a first and second source/drain;

said first source/drain of said third transistor coupled to said first source/drain of said fourth transistor;

said second source/drain of said third transistor coupled to said second source/drain of said first transistor; and

said second source/drain of said fourth transistor coupled to said first source/drain of said second transistor.

10. The switching circuit of claim 9 further including a capacitor coupled between said first source/drain of both of said third and fourth transistors and ground.

11. A switching circuit as set forth in claim 7 further including an input terminal coupled to said first switch and an output terminal coupled to said second switch, a first capacitor coupled between said input terminal and said first switch and a second capacitor coupled between said output terminal and said second switch.

12. A switching circuit as set forth in claim 8 further including an input terminal coupled to said first switch and an output terminal coupled to said second switch, a first capacitor coupled between said input terminal and said first switch and a second capacitor coupled between said output terminal and said second switch.

13. A switching circuit as set forth in claim 9 further including an input terminal coupled to said first switch and an output terminal coupled to said second switch, a first capacitor coupled between said input terminal and said first switch and a second capacitor coupled between said output terminal and said second switch.

14. A switching circuit as set forth in claim 10 further including an input terminal coupled to said first switch and an output terminal coupled to said second switch, a first capacitor coupled between said input terminal and said first switch and a second capacitor coupled between said output terminal and said second switch.

15. A switching circuit, comprising:

(a) an input terminal, an output terminal and a floating switching circuit coupled between said input terminal and said output terminal, said floating switching circuit comprising;

(i) a first current path;

(ii) a first switch having an input end and an output end disposed in said first current path controlling current flow in said first current path, said input end of said first switch coupled to said input terminal and said output end of said first switch coupled to said output terminal, said first switch having a control input for receiving a first control voltage to control operation of said first switch;

(iii) a second current path;

(iv) a second switch having an input end and output end disposed in said second current path controlling current flow in said second current path, said input end of said second switch coupled to said first current path at said output end of said first switch and said output end of said second switch coupled to a reference source, said second switch having a control input for receiving a second control voltage to control operation of said second switch, only one of said first switch and said second switch being operable to conduct in response to a voltage difference between said first and second control voltages;

(v) a first capacitor in said first current path serially coupled between said input terminal and said input end of said first switch;

(vi) a second capacitor in said second current path serially coupled between said output terminal, the output end of said first switch and the input end of said second switch; and

(vii) a third capacitor serially coupled between said output end of said second switch and said reference source.

16. The switching circuit of claim 15 wherein said first switch comprises a first transistor having a gate providing said control input for said first switch and said second switch comprises a second transistor having a gate providing said control input for said second switch.

17. The switching circuit of claim 16 wherein said first transistor further comprises a first and a second source/drain and said second transistor further comprises a first and a second source/drain, and wherein said first source/drain of said first transistor is connected to receive an input signal from said input terminal and said second source/drain of said first transistor is connected to transmit an output signal to said output terminal.

18. The switching circuit of claim 17 wherein said first source/drain of said second transistor is coupled to said second source/drain of said first transistor.

19. A switching circuit, comprising:

(a) an input terminal, an output terminal and a floating switching circuit coupled between said input terminal and said output terminal, said floating switching circuit comprising;

(i) a first transistor having a first and a second source/drain, said first source/drain coupled to said input terminal and said second source/drain coupled to said output terminal, said first transistor having agate for receiving a first control voltage;

(ii) a second transistor having a third and a fourth source/drain, said third source/drain coupled to said output terminal, said second transistor having a gate for receiving a second control voltage;

(iii) only one of said first transistor or said second transistor being rendered conductive responsive to the difference between said first and second control voltages;

(iv) a first capacitor serially coupled between said input terminal and said first source/drain of said first transistor to electrically isolate said input terminal from said first transistor;

(v) a second capacitor serially coupled between said output terminal and each of said second and third source/drains to electrically isolate said output terminal from said first and second transistors; and

(vi) a third capacitor serially coupled between said fourth source/drain and a source of reference voltage to electrically isolate said source of reference voltage from said second transistor.