Switched charge voltage driver and method for applying voltage to tunable dielectric devices

• US 6,535,076 B2
• Filed: 05/15/2001
• Issued: 03/18/2003
• Est. Priority Date: 05/15/2001
• Status: Expired due to Term

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: GATX Ventures, Inc. (GATX Corp.), Silicon Valley Bank (SVB Financial Group)
• Inventors: Henderson, Herbert Jefferson, Acsadi, Peter, Omictin, Guy, Robinson, John, Partridge, Alden
• Primary Examiner(s): Ham, Seungsook
• Application Number:
  US09/855,949
• Publication Number:
  US 20020171502A1
• Time in Patent Office: 672 Days
• Field of Search: 333/17.1, 333/139, 333/164, 333/205, 333/235, 333/156, 327/530, 307/125, 307/130
• US Class Current: 333/17.1
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps

Abstract

A circuit for providing a control voltage for tunable dielectric devices, the circuit comprising an input for receiving a voltage command signal, a charging circuit for establishing a desired voltage level on a first capacitor in response to the voltage command signal, and a switch for switching voltage on the first capacitor to a tunable dielectric device to control a dielectric constant of tunable dielectric material in the tunable dielectric device. A second capacitor, second charging circuit, and second switch can be used to provide voltage to the tunable dielectric device during charging or discharging of the first capacitor. The method for providing a control voltage for tunable dielectric devices performed by these circuits is also included.

Claims

1. A circuit for providing a control voltage for tunable dielectric devices, the circuit comprising:

means for receiving a voltage command signal;

means for establishing a desired voltage level on a first capacitor in response to the voltage command signal; and

means for switching voltage on the first capacitor to a tunable dielectric device to control a dielectric constant of tunable dielectric material in the tunable dielectric device.

2. The circuit of claim 1, wherein the means for establishing a desired voltage level on the first capacitor in response to the voltage command signal comprises:

means for alternatively charging the first capacitor to the desired voltage level if a pre-existing voltage level on the first capacitor is less than the desired voltage level, or discharging the first capacitor to the desired voltage level if the pre-existing voltage level on the first capacitor is greater than the desired voltage level.

3. The circuit of claim 1, wherein the means for establishing a desired voltage level on the first capacitor in response to the voltage command signal comprises:

means for producing a first voltage signal representative of the voltage command signal;

means for comparing the first voltage signal to a second voltage signal representative of a pre-existing voltage on the first capacitor;

means for alternatively charging the first capacitor if the first voltage signal exceeds the second voltage signal or discharging the first capacitor if the second voltage signal exceeds the first voltage signal.

4. The circuit of claim 1, further comprising:

means for establishing a desired voltage level on a second capacitor in response to the voltage command signal; and

means for switching voltage on the second capacitor to the tunable dielectric device to control the dielectric constant of the tunable dielectric material in the tunable dielectric device.

5. The circuit of claim 4, wherein:

the means for establishing a desired voltage level on the first capacitor in response to the voltage command signal comprises means for alternatively charging the first capacitor to the desired voltage level if a pre-existing voltage level on the first capacitor is less than the desired voltage level, or discharging the first capacitor to the desired voltage level if the pre-existing voltage level on the first capacitor is greater than the desired voltage level; and

the means for establishing a desired voltage level on the second capacitor in response to the voltage command signal comprises means for alternatively charging the second capacitor to the desired voltage level if a pre-existing voltage level on the second capacitor is less than the desired voltage level, or discharging the second capacitor to the desired voltage level if the pre-existing voltage level on the second capacitor is greater than the desired voltage level.

6. The circuit of claim 4, further comprising:

means for producing a first voltage signal representative of the voltage command signal; and

wherein the means for establishing a desired voltage level on the first capacitor in response to the voltage command signal comprises means for comparing the first voltage signal to a second voltage signal representative of a pre-existing voltage on the first capacitor, and means for alternatively charging the first capacitor if the first voltage signal exceeds the second voltage signal or discharging the first capacitor if the second voltage signal exceeds the first voltage signal;

wherein the means for establishing a desired voltage level on the second capacitor in response to the voltage command signal comprises means for comparing the first voltage signal to a third voltage signal representative of a pre-existing voltage on the second capacitor, and means for alternatively charging the second capacitor if the first voltage signal exceeds the third voltage signal or discharging the second capacitor if the third voltage signal exceeds the first voltage signal.

7. A circuit for providing a control voltage for tunable dielectric devices, the method comprising:

an input for receiving a voltage command signal;

a first capacitor;

a first charging circuit for charging the first capacitor to a desired voltage level in response to the voltage command signal; and

a first switch for connecting the first capacitor to a tunable dielectric device to control a dielectric constant of tunable dielectric material in the tunable dielectric device.

8. The circuit of claim 7, wherein the first charging circuit for charging the first capacitor to a desired voltage level comprises:

a first comparator for comparing a first voltage signal representative of a pre-existing voltage on the first capacitor with a second voltage signal representative of the voltage command signal;

a second switch for connecting the first capacitor to a first voltage source when the first voltage signal representative of the pre-existing voltage on the first capacitor is less than the second voltage signal representative of the voltage command signal.

9. The circuit of claim 8, further comprising:

a second capacitor;

a second charging circuit for charging the second capacitor to a desired voltage level; and

a third switch for connecting the second capacitor to the tunable dielectric device to control the dielectric constant of the tunable dielectric material in the tunable dielectric device.

10. The circuit of claim 9, wherein the second charging circuit for charging the second capacitor to a desired voltage level comprises:

a second comparator for comparing a third voltage signal representative of a pre-existing voltage on the second capacitor with a fourth voltage signal representative of the voltage command signal;

a fourth switch for connecting the second capacitor to the first voltage source when the third voltage signal representative of the pre-existing voltage on the second capacitor is less than the fourth voltage signal representative of the voltage command signal.

11. The circuit of claim 8, wherein the first charging circuit for charging the first capacitor to a desired voltage level further comprises:

a second comparator for comparing the first voltage signal representative of the pre-existing voltage on the first capacitor with a third voltage signal representative of the voltage command signal; and

a third switch for connecting the first capacitor to a second voltage source when first voltage signal representative of the pre-existing voltage on the first capacitor is greater than the third voltage signal representative of the voltage command signal.

12. The circuit of claim 11, further comprising:

a second capacitor;

a second charging circuit for charging the second capacitor to a desired voltage level; and

a fourth switch for connecting the second capacitor to the tunable dielectric device to control the dielectric constant of the tunable dielectric material in the tunable dielectric device.

13. The circuit of claim 12, wherein the second charging circuit for charging the second capacitor to a desired voltage level comprises:

a third comparator for comparing a fourth voltage signal representative of a pre-existing voltage on the second capacitor with a fifth voltage signal representative of the voltage command signal;

a fifth switch for connecting the second capacitor to the first voltage source when the fourth voltage signal representative of the pre-existing voltage on the second capacitor is less than the fifth voltage signal representative of the voltage command signal.

14. The circuit of claim 13, wherein the second charging circuit for charging the second capacitor to a desired voltage level further comprises:

a fourth comparator for comparing a sixth voltage signal representative of the pre-existing voltage on the second capacitor with a seventh voltage signal representative of the voltage command signal; and

a sixth switch for connecting the second capacitor to the second voltage source when the sixth voltage signal representative of the pre-existing voltage on the second capacitor is greater than the seventh voltage signal representative of the voltage command signal.

15. A method for providing a control voltage for tunable dielectric devices, the method comprising the steps of:

receiving a voltage command signal;

establishing a desired voltage level on a first capacitor in response to the voltage command signal; and

switching voltage on the first capacitor to a tunable dielectric device to control a dielectric constant of tunable dielectric material in the tunable dielectric device.

16. The method of claim 15, wherein the step of establishing a desired voltage level on the first capacitor in response to the voltage command signal comprises the steps of:

alternatively charging the first capacitor to the desired voltage level if a pre-existing voltage level on the first capacitor is less than the desired voltage level, or discharging the first capacitor to the desired voltage level if the pre-existing voltage level on the first capacitor is greater than the desired voltage level.

17. The method of claim 15, wherein the step of establishing a desired voltage level on the first capacitor in response to the voltage command signal comprises the steps of:

producing a first voltage signal representative of the voltage command signal;

comparing the first voltage signal to a second voltage signal representative of a pre-existing voltage on the first capacitor;

alternatively charging the first capacitor if the first voltage signal exceeds the second voltage signal or discharging the first capacitor if the second voltage signal exceeds the first voltage signal.

18. The method of claim 15, further comprising the steps of:

establishing a desired voltage level on a second capacitor in response to the voltage command signal; and

switching voltage on the second capacitor to the tunable dielectric device to control the dielectric constant of the tunable dielectric material in the tunable dielectric device.

19. The method of claim 18, wherein the step of establishing a desired voltage level on the second capacitor in response to the voltage command signal comprises the steps of:

alternatively charging the second capacitor to the desired voltage level if a pre-existing voltage level on the second capacitor is less than the desired voltage level;

or discharging the second capacitor to the desired voltage level if a pre-existing voltage level on the second capacitor is greater than the desired voltage level.

20. The method of claim 18, wherein the step of establishing a desired voltage level on the second capacitor in response to the voltage command signal comprises the steps of:

producing a first voltage signal representative of the voltage command signal;

comparing the first voltage signal to a second voltage signal representative of a pre-existing voltage on the first capacitor;

alternatively charging the first capacitor if the first voltage signal exceeds the second voltage signal or discharging the second capacitor if the second voltage signal exceeds the first voltage signal;

producing a third voltage signal representative of the voltage command signal;

comparing the third voltage signal to a fourth voltage signal representative of a pre-existing voltage on the second capacitor; and

alternatively charging the second capacitor if the third voltage signal exceeds the fourth voltage signal or discharging the second capacitor if the fourth voltage signal exceeds the third voltage signal.