Claims
- 1. A voltage comparator circuit comprising:
- a comparator stage comprising:
- a first comparator input terminal;
- a second comparator input terminal;
- a third comparator input terminal;
- a fourth comparator input terminal;
- a first comparator output terminal; and
- a second comparator output terminal,
- said comparator stage producing a first comparator output voltage at said first comparator output terminal equal to one of a first comparator voltage and a second comparator voltage and producing a second comparator output voltage at said second comparator output terminal equal to one of said second comparator voltage and a third comparator voltage, in response to a first comparator input voltage applied to said first comparator input terminal, a second comparator input voltage applied to said second comparator input terminal, and a third comparator input voltage applied to said third comparator input terminal; and
- a switch comprising a first switch input terminal and a second switch input terminal in electrical communication with said first comparator output terminal and said second comparator output terminal, respectively, and a switch output terminal in electrical communication with said fourth comparator input terminal, said switch producing a switch output voltage at said switch output terminal substantially equal to one of a first reference voltage and a second reference voltage in response to a first switch input voltage applied to said first switch input terminal and a second switch input voltage applied to said second switch input terminal.
- 2. The voltage comparator circuit of claim 1 wherein said first comparator output voltage is substantially equal to said first comparator voltage and said second comparator output voltage is substantially equal to said second comparator voltage when said second comparator input voltage applied to said second comparator input terminal is greater than said first comparator input voltage applied to said first comparator input terminal.
- 3. The voltage comparator circuit of claim 1 wherein said switch output voltage is substantially equal to said second reference voltage when a voltage substantially equal to said second comparator voltage is applied to said first switch input terminal and a voltage substantially equal to said first comparator voltage is applied to said second switch input terminal.
- 4. A voltage comparator circuit comprising:
- a comparator stage comprising:
- a first comparator input terminal;
- a second comparator input terminal;
- a third comparator input terminal;
- a fourth comparator input terminal;
- a first comparator output terminal; and
- a second comparator output terminal,
- said comparator stage producing a first comparator output voltage at said first comparator output terminal equal to one of a first comparator voltage and a second comparator voltage and producing a second comparator output voltage at said second comparator output terminal equal to one of said second comparator voltage and a third comparator voltage, in response to a first comparator input voltage applied to said first comparator input terminal and a second comparator input voltage applied to said second comparator input terminal;
- an inverting gain stage comprising:
- a first gain input terminal and a second gain input terminal in electrical communication with said first comparator output terminal and said second comparator output terminal, respectively;
- a first gain output terminal; and
- a second gain output terminal,
- said inverting gain stage producing a first gain output voltage at said first gain output terminal equal to one of a first gain voltage and a second gain voltage and a second gain output voltage at said second gain output terminal substantially equal to one of said second gain voltage and a third gain voltage in response to a first gain input voltage applied to said first gain input terminal and a second gain input voltage applied to said second gain input terminal; and
- a switch comprising a first switch input terminal and a second switch input terminal in electrical communication with said first gain output terminal and said second gain output terminal, respectively, a third switch input terminal, a fourth switch input terminal, and a switch output terminal in electrical communication with said fourth comparator input terminal, said switch producing a switch output voltage at said switch output terminal substantially equal to one of a first reference voltage applied to said third switch input terminal and a second reference voltage applied to said fourth switch input terminal in response to a first switch input voltage applied to said first switch input terminal and a second switch input voltage applied to said second switch input terminal.
- 5. The voltage comparator circuit of claim 4 wherein said first comparator output voltage is substantially equal to said first comparator voltage and said second comparator output voltage is substantially equal to said second comparator voltage when said second comparator input voltage applied to said second comparator input terminal is greater than said first comparator input voltage applied to said first comparator input terminal.
- 6. The voltage comparator circuit of claim 4 wherein said first gain output voltage is substantially equal to said second comparator voltage and said second gain output voltage is substantially equal said first comparator voltage when said first gain input voltage applied to said first gain input terminal is substantially equal to said first comparator voltage and said second gain input voltage applied to said second gain input terminal is substantially equal to said second comparator voltage.
- 7. The voltage comparator circuit of claim 4 wherein said switch output voltage is substantially equal to said second reference voltage applied to said fourth switch input terminal when a voltage substantially equal to said second comparator voltage is applied to said first switch input terminal and a voltage substantially equal to said first comparator voltage is applied to said second switch input terminal.
- 8. The voltage comparator circuit of claim 4 wherein said inverting gain stage further comprises a third gain input terminal for application of a third gain input voltage substantially equal to said first comparator input voltage and a fourth gain input terminal for application of a fourth gain input voltage substantially equal to said second comparator input voltage.
- 9. A voltage comparator circuit comprising:
- a comparator stage comprising first, second, third, and fourth comparator input terminals, and first and second comparator output terminals, said comparator stage producing a first comparator output voltage at said first comparator output terminal substantially equal to one of a first reference voltage applied to said first comparator input terminal and a third reference voltage applied to said third comparator input terminal in response to said first reference voltage applied to said first comparator input terminal and a second reference voltage applied to said second comparator input terminal, said comparator stage producing a second comparator output voltage at said second comparator output terminal substantially equal to one of said second reference voltage applied to said second comparator input terminal and said third reference voltage applied to said third comparator input terminal in response to said first reference voltage applied to said first comparator input terminal and said second reference voltage applied to said second comparator input terminal;
- an inverting gain stage comprising first, second, third, fourth, and fifth gain input terminals, and first and second gain output terminals, said first and second gain input terminals in electrical communication with said first and second comparator output terminals, respectively, said inverting gain stage producing a first gain output voltage at said first gain output terminal substantially equal to one of a second gain input voltage applied to said second gain input terminal and said third reference voltage applied to said third gain input terminal in response to a first gain input voltage applied to said first gain input terminal and said second gain input voltage applied to said second gain input terminal, said inverting gain stage producing a second gain output voltage at said second gain output terminal substantially equal to one of said first gain input voltage applied to said first gain terminal and said third reference voltage applied to said third gain input terminal in response to said first gain input voltage applied to said first gain input terminal and said second gain input voltage applied to said second gain input terminal; and
- a switch comprising first and second switch input terminals in electrical communication with said first and second gain output terminals, respectively, third and fourth switch input terminals in electrical communication with said first and second comparator input terminals, respectively, and a switch output terminal in electrical communication with said fourth comparator input terminal, said switch producing a switch output voltage at said switch output terminal substantially equal to one of said first reference voltage applied to said third switch input terminal and said second reference voltage applied to said fourth switch input terminal in response to a first switch voltage applied to said first switch input terminal and a second switch voltage applied to said second switch input terminal.
- 10. A method for applying one of a first reference voltage and a second reference voltage to a circuit, comprising the steps of:
- comparing a first reference voltage and a second reference voltage;
- generating a first output voltage substantially equal to one of said second reference voltage and a third reference voltage in response to said comparison and further in response to a third input voltage;
- generating a second output voltage substantially equal to one of said first and third reference voltages in response to said comparison and further in response to said third input voltage; and
- generating a voltage comparator output voltage substantially equal to one of said first and second reference voltages in response to said first and second output voltages.
- 11. The method of claim 10 further comprising the step of applying said voltage comparator output voltage as said third input voltage.
- 12. A method for applying one of a first reference voltage and a second reference voltage to a circuit, comprising the steps of:
- comparing a first reference voltage and a second reference voltage;
- generating a first output voltage substantially equal to one of said second reference voltage and a third reference voltage in response to said comparison;
- generating a second output voltage substantially equal to one of said first and third reference voltages in response to said comparison;
- generating a third output voltage substantially equal to one of said first and third reference voltages in response to said first and second output voltages;
- generating a fourth output voltage substantially equal to one of said second and third reference voltages in response to said first and second output voltages; and
- generating a voltage comparator output voltage substantially equal to one of said first and second reference voltages in response to said third and fourth output voltages.
RELATED APPLICATIONS
This application claims priority to pending provisional application, Ser. No. 60/060,831, filed on Oct. 1, 1997, the contents of which are incorporated herein by reference.
US Referenced Citations (3)